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Posted to commits@kudu.apache.org by ab...@apache.org on 2018/10/26 18:57:43 UTC
[50/52] [abbrv] [partial] kudu git commit: Updating web site for Kudu
1.8.0 release
http://git-wip-us.apache.org/repos/asf/kudu/blob/1fefa84c/docs
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----
-title: Apache Kudu Administration
-layout: default
-active_nav: docs
-last_updated: 'Last updated 2018-06-15 07:22:05 PDT'
----
-<!--
-
-Licensed under the Apache License, Version 2.0 (the "License");
-you may not use this file except in compliance with the License.
-You may obtain a copy of the License at
-
- http://www.apache.org/licenses/LICENSE-2.0
-
-Unless required by applicable law or agreed to in writing, software
-distributed under the License is distributed on an "AS IS" BASIS,
-WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-See the License for the specific language governing permissions and
-limitations under the License.
--->
-
-
-<div class="container">
- <div class="row">
- <div class="col-md-9">
-
-<h1>Apache Kudu Administration</h1>
- <div id="preamble">
-<div class="sectionbody">
-<div class="admonitionblock note">
-<table>
-<tr>
-<td class="icon">
-<i class="fa icon-note" title="Note"></i>
-</td>
-<td class="content">
-Kudu is easier to manage with <a href="http://www.cloudera.com/content/www/en-us/products/cloudera-manager.html">Cloudera Manager</a>
-than in a standalone installation. See Cloudera’s
-<a href="http://www.cloudera.com/documentation/kudu/latest/topics/kudu_installation.html">Kudu documentation</a>
-for more details about using Kudu with Cloudera Manager.
-</td>
-</tr>
-</table>
-</div>
-</div>
-</div>
-<div class="sect1">
-<h2 id="_starting_and_stopping_kudu_processes"><a class="link" href="#_starting_and_stopping_kudu_processes">Starting and Stopping Kudu Processes</a></h2>
-<div class="sectionbody">
-<div class="admonitionblock note">
-<table>
-<tr>
-<td class="icon">
-<i class="fa icon-note" title="Note"></i>
-</td>
-<td class="content">
-These instructions are relevant only when Kudu is installed using operating system packages
-(e.g. <code>rpm</code> or <code>deb</code>).
-</td>
-</tr>
-</table>
-</div>
-<div class="olist arabic">
-<ol class="arabic">
-<li>
-<p>Start Kudu services using the following commands:</p>
-<div class="listingblock">
-<div class="content">
-<pre class="highlight"><code class="language-bash" data-lang="bash">$ sudo service kudu-master start
-$ sudo service kudu-tserver start</code></pre>
-</div>
-</div>
-</li>
-<li>
-<p>To stop Kudu services, use the following commands:</p>
-<div class="listingblock">
-<div class="content">
-<pre class="highlight"><code class="language-bash" data-lang="bash">$ sudo service kudu-master stop
-$ sudo service kudu-tserver stop</code></pre>
-</div>
-</div>
-</li>
-</ol>
-</div>
-</div>
-</div>
-<div class="sect1">
-<h2 id="_kudu_web_interfaces"><a class="link" href="#_kudu_web_interfaces">Kudu Web Interfaces</a></h2>
-<div class="sectionbody">
-<div class="paragraph">
-<p>Kudu tablet servers and masters expose useful operational information on a built-in web interface,</p>
-</div>
-<div class="sect2">
-<h3 id="_kudu_master_web_interface"><a class="link" href="#_kudu_master_web_interface">Kudu Master Web Interface</a></h3>
-<div class="paragraph">
-<p>Kudu master processes serve their web interface on port 8051. The interface exposes several pages
-with information about the cluster state:</p>
-</div>
-<div class="ulist">
-<ul>
-<li>
-<p>A list of tablet servers, their host names, and the time of their last heartbeat.</p>
-</li>
-<li>
-<p>A list of tables, including schema and tablet location information for each.</p>
-</li>
-<li>
-<p>SQL code which you can paste into Impala Shell to add an existing table to Impala’s list of known data sources.</p>
-</li>
-</ul>
-</div>
-</div>
-<div class="sect2">
-<h3 id="_kudu_tablet_server_web_interface"><a class="link" href="#_kudu_tablet_server_web_interface">Kudu Tablet Server Web Interface</a></h3>
-<div class="paragraph">
-<p>Each tablet server serves a web interface on port 8050. The interface exposes information
-about each tablet hosted on the server, its current state, and debugging information
-about maintenance background operations.</p>
-</div>
-</div>
-<div class="sect2">
-<h3 id="_common_web_interface_pages"><a class="link" href="#_common_web_interface_pages">Common Web Interface Pages</a></h3>
-<div class="paragraph">
-<p>Both Kudu masters and tablet servers expose a common set of information via their web interfaces:</p>
-</div>
-<div class="ulist">
-<ul>
-<li>
-<p>HTTP access to server logs.</p>
-</li>
-<li>
-<p>an <code>/rpcz</code> endpoint which lists currently running RPCs via JSON.</p>
-</li>
-<li>
-<p>pages giving an overview and detailed information on the memory usage of different
-components of the process.</p>
-</li>
-<li>
-<p>information on the current set of configuration flags.</p>
-</li>
-<li>
-<p>information on the currently running threads and their resource consumption.</p>
-</li>
-<li>
-<p>a JSON endpoint exposing metrics about the server.</p>
-</li>
-<li>
-<p>information on the deployed version number of the daemon.</p>
-</li>
-</ul>
-</div>
-<div class="paragraph">
-<p>These interfaces are linked from the landing page of each daemon’s web UI.</p>
-</div>
-</div>
-</div>
-</div>
-<div class="sect1">
-<h2 id="_kudu_metrics"><a class="link" href="#_kudu_metrics">Kudu Metrics</a></h2>
-<div class="sectionbody">
-<div class="paragraph">
-<p>Kudu daemons expose a large number of metrics. Some metrics are associated with an entire
-server process, whereas others are associated with a particular tablet replica.</p>
-</div>
-<div class="sect2">
-<h3 id="_listing_available_metrics"><a class="link" href="#_listing_available_metrics">Listing available metrics</a></h3>
-<div class="paragraph">
-<p>The full set of available metrics for a Kudu server can be dumped via a special command
-line flag:</p>
-</div>
-<div class="listingblock">
-<div class="content">
-<pre class="highlight"><code class="language-bash" data-lang="bash">$ kudu-tserver --dump_metrics_json
-$ kudu-master --dump_metrics_json</code></pre>
-</div>
-</div>
-<div class="paragraph">
-<p>This will output a large JSON document. Each metric indicates its name, label, description,
-units, and type. Because the output is JSON-formatted, this information can easily be
-parsed and fed into other tooling which collects metrics from Kudu servers.</p>
-</div>
-</div>
-<div class="sect2">
-<h3 id="_collecting_metrics_via_http"><a class="link" href="#_collecting_metrics_via_http">Collecting metrics via HTTP</a></h3>
-<div class="paragraph">
-<p>Metrics can be collected from a server process via its HTTP interface by visiting
-<code>/metrics</code>. The output of this page is JSON for easy parsing by monitoring services.
-This endpoint accepts several <code>GET</code> parameters in its query string:</p>
-</div>
-<div class="ulist">
-<ul>
-<li>
-<p><code>/metrics?metrics=<substring1>,<substring2>,…​</code> - limits the returned metrics to those which contain
-at least one of the provided substrings. The substrings also match entity names, so this
-may be used to collect metrics for a specific tablet.</p>
-</li>
-<li>
-<p><code>/metrics?include_schema=1</code> - includes metrics schema information such as unit, description,
-and label in the JSON output. This information is typically elided to save space.</p>
-</li>
-<li>
-<p><code>/metrics?compact=1</code> - eliminates unnecessary whitespace from the resulting JSON, which can decrease
-bandwidth when fetching this page from a remote host.</p>
-</li>
-<li>
-<p><code>/metrics?include_raw_histograms=1</code> - include the raw buckets and values for histogram metrics,
-enabling accurate aggregation of percentile metrics over time and across hosts.</p>
-</li>
-</ul>
-</div>
-<div class="paragraph">
-<p>For example:</p>
-</div>
-<div class="listingblock">
-<div class="content">
-<pre class="highlight"><code class="language-bash" data-lang="bash">$ curl -s 'http://example-ts:8050/metrics?include_schema=1&metrics=connections_accepted'</code></pre>
-</div>
-</div>
-<div class="listingblock">
-<div class="content">
-<pre class="highlight"><code class="language-json" data-lang="json">[
- {
- "type": "server",
- "id": "kudu.tabletserver",
- "attributes": {},
- "metrics": [
- {
- "name": "rpc_connections_accepted",
- "label": "RPC Connections Accepted",
- "type": "counter",
- "unit": "connections",
- "description": "Number of incoming TCP connections made to the RPC server",
- "value": 92
- }
- ]
- }
-]</code></pre>
-</div>
-</div>
-<div class="listingblock">
-<div class="content">
-<pre class="highlight"><code class="language-bash" data-lang="bash">$ curl -s 'http://example-ts:8050/metrics?metrics=log_append_latency'</code></pre>
-</div>
-</div>
-<div class="listingblock">
-<div class="content">
-<pre class="highlight"><code class="language-json" data-lang="json">[
- {
- "type": "tablet",
- "id": "c0ebf9fef1b847e2a83c7bd35c2056b1",
- "attributes": {
- "table_name": "lineitem",
- "partition": "hash buckets: (55), range: [(<start>), (<end>))",
- "table_id": ""
- },
- "metrics": [
- {
- "name": "log_append_latency",
- "total_count": 7498,
- "min": 4,
- "mean": 69.3649,
- "percentile_75": 29,
- "percentile_95": 38,
- "percentile_99": 45,
- "percentile_99_9": 95,
- "percentile_99_99": 167,
- "max": 367244,
- "total_sum": 520098
- }
- ]
- }
-]</code></pre>
-</div>
-</div>
-<div class="admonitionblock note">
-<table>
-<tr>
-<td class="icon">
-<i class="fa icon-note" title="Note"></i>
-</td>
-<td class="content">
-All histograms and counters are measured since the server start time, and are not reset upon collection.
-</td>
-</tr>
-</table>
-</div>
-</div>
-<div class="sect2">
-<h3 id="_diagnostics_logging"><a class="link" href="#_diagnostics_logging">Diagnostics Logging</a></h3>
-<div class="paragraph">
-<p>Kudu may be configured to dump various diagnostics information to a local log file.
-The diagnostics log will be written to the same directory as the other Kudu log files, with a
-similar naming format, substituting <code>diagnostics</code> instead of a log level like <code>INFO</code>.
-After any diagnostics log file reaches 64MB uncompressed, the log will be rolled and
-the previous file will be gzip-compressed.</p>
-</div>
-<div class="paragraph">
-<p>Each line in the diagnostics log consists of the following components:</p>
-</div>
-<div class="ulist">
-<ul>
-<li>
-<p>A human-readable timestamp formatted in the same fashion as the other Kudu log files.</p>
-</li>
-<li>
-<p>The type of record. For example, a metrics record consists of the word <code>metrics</code>.</p>
-</li>
-<li>
-<p>A machine-readable timestamp, in microseconds since the Unix epoch.</p>
-</li>
-<li>
-<p>The record itself.</p>
-</li>
-</ul>
-</div>
-<div class="paragraph">
-<p>Currently, the only type of diagnostics record is a periodic dump of the server metrics.
-Each record is encoded in compact JSON format, and the server attempts to elide any metrics
-which have not changed since the previous record. In addition, counters which have never
-been incremented are elided. Otherwise, the format of the JSON record is identical to the
-format exposed by the HTTP endpoint above.</p>
-</div>
-<div class="paragraph">
-<p>The frequency with which metrics are dumped to the diagnostics log is configured using the
-<code>--metrics_log_interval_ms</code> flag. By default, Kudu logs metrics every 60 seconds.</p>
-</div>
-</div>
-</div>
-</div>
-<div class="sect1">
-<h2 id="_common_kudu_workflows"><a class="link" href="#_common_kudu_workflows">Common Kudu workflows</a></h2>
-<div class="sectionbody">
-<div class="sect2">
-<h3 id="migrate_to_multi_master"><a class="link" href="#migrate_to_multi_master">Migrating to Multiple Kudu Masters</a></h3>
-<div class="paragraph">
-<p>For high availability and to avoid a single point of failure, Kudu clusters should be created with
-multiple masters. Many Kudu clusters were created with just a single master, either for simplicity
-or because Kudu multi-master support was still experimental at the time. This workflow demonstrates
-how to migrate to a multi-master configuration. It can also be used to migrate from two masters to
-three, with straightforward modifications.</p>
-</div>
-<div class="admonitionblock warning">
-<table>
-<tr>
-<td class="icon">
-<i class="fa icon-warning" title="Warning"></i>
-</td>
-<td class="content">
-The workflow is unsafe for adding new masters to an existing configuration that already has
-three or more masters. Do not use it for that purpose.
-</td>
-</tr>
-</table>
-</div>
-<div class="admonitionblock warning">
-<table>
-<tr>
-<td class="icon">
-<i class="fa icon-warning" title="Warning"></i>
-</td>
-<td class="content">
-All of the command line steps below should be executed as the Kudu UNIX user. The example
-commands assume the Kudu Unix user is <code>kudu</code>, which is typical.
-</td>
-</tr>
-</table>
-</div>
-<div class="admonitionblock warning">
-<table>
-<tr>
-<td class="icon">
-<i class="fa icon-warning" title="Warning"></i>
-</td>
-<td class="content">
-The workflow presupposes at least basic familiarity with Kudu configuration management. If
-using Cloudera Manager (CM), the workflow also presupposes familiarity with it.
-</td>
-</tr>
-</table>
-</div>
-<div class="sect3">
-<h4 id="_prepare_for_the_migration"><a class="link" href="#_prepare_for_the_migration">Prepare for the migration</a></h4>
-<div class="olist arabic">
-<ol class="arabic">
-<li>
-<p>Establish a maintenance window (one hour should be sufficient). During this time the Kudu cluster
-will be unavailable.</p>
-</li>
-<li>
-<p>Decide how many masters to use. The number of masters should be odd. Three or five node master
-configurations are recommended; they can tolerate one or two failures respectively.</p>
-</li>
-<li>
-<p>Perform the following preparatory steps for the existing master:</p>
-<div class="ulist">
-<ul>
-<li>
-<p>Identify and record the directories where the master’s write-ahead log (WAL) and data live. If
-using Kudu system packages, their default locations are /var/lib/kudu/master, but they may be
-customized via the <code>fs_wal_dir</code> and <code>fs_data_dirs</code> configuration parameters. The commands below
-assume that <code>fs_wal_dir</code> is /data/kudu/master/wal and <code>fs_data_dirs</code> is /data/kudu/master/data.
-Your configuration may differ. For more information on configuring these directories, see the
-<a href="configuration.html#directory_configuration">Kudu Configuration docs</a>.</p>
-</li>
-<li>
-<p>Identify and record the port the master is using for RPCs. The default port value is 7051, but it
-may have been customized using the <code>rpc_bind_addresses</code> configuration parameter.</p>
-</li>
-<li>
-<p>Identify the master’s UUID. It can be fetched using the following command:</p>
-<div class="listingblock">
-<div class="content">
-<pre class="highlight"><code class="language-bash" data-lang="bash">$ sudo -u kudu kudu fs dump uuid --fs_wal_dir=<master_wal_dir> [--fs_data_dirs=<master_data_dirs>] 2>/dev/null</code></pre>
-</div>
-</div>
-<div class="dlist">
-<dl>
-<dt class="hdlist1">master_data_dir</dt>
-<dd>
-<p>existing master’s previously recorded data directory</p>
-</dd>
-<dt class="hdlist1">Example</dt>
-<dd>
-<div class="listingblock">
-<div class="content">
-<pre>$ sudo -u kudu kudu fs dump uuid --fs_wal_dir=/data/kudu/master/wal --fs_data_dirs=/data/kudu/master/data 2>/dev/null
-4aab798a69e94fab8d77069edff28ce0</pre>
-</div>
-</div>
-</dd>
-</dl>
-</div>
-</li>
-<li>
-<p>Optional: configure a DNS alias for the master. The alias could be a DNS cname (if the machine
-already has an A record in DNS), an A record (if the machine is only known by its IP address),
-or an alias in /etc/hosts. The alias should be an abstract representation of the master (e.g.
-<code>master-1</code>).</p>
-<div class="admonitionblock warning">
-<table>
-<tr>
-<td class="icon">
-<i class="fa icon-warning" title="Warning"></i>
-</td>
-<td class="content">
-Without DNS aliases it is not possible to recover from permanent master failures without
-bringing the cluster down for maintenance, and as such, it is highly recommended.
-</td>
-</tr>
-</table>
-</div>
-</li>
-</ul>
-</div>
-</li>
-<li>
-<p>If you have Kudu tables that are accessed from Impala, you must update
-the master addresses in the Apache Hive Metastore (HMS) database.</p>
-<div class="ulist">
-<ul>
-<li>
-<p>If you set up the DNS aliases, run the following statement in <code>impala-shell</code>,
-replacing <code>master-1</code>, <code>master-2</code>, and <code>master-3</code> with your actual aliases.</p>
-<div class="listingblock">
-<div class="content">
-<pre class="highlight"><code class="language-sql" data-lang="sql">ALTER TABLE table_name
-SET TBLPROPERTIES
-('kudu.master_addresses' = 'master-1,master-2,master-3');</code></pre>
-</div>
-</div>
-</li>
-<li>
-<p>If you do not have DNS aliases set up, see Step #11 in the Performing
-the migration section for updating HMS.</p>
-</li>
-</ul>
-</div>
-</li>
-<li>
-<p>Perform the following preparatory steps for each new master:</p>
-<div class="ulist">
-<ul>
-<li>
-<p>Choose an unused machine in the cluster. The master generates very little load so it can be
-colocated with other data services or load-generating processes, though not with another Kudu
-master from the same configuration.</p>
-</li>
-<li>
-<p>Ensure Kudu is installed on the machine, either via system packages (in which case the <code>kudu</code> and
-<code>kudu-master</code> packages should be installed), or via some other means.</p>
-</li>
-<li>
-<p>Choose and record the directory where the master’s data will live.</p>
-</li>
-<li>
-<p>Choose and record the port the master should use for RPCs.</p>
-</li>
-<li>
-<p>Optional: configure a DNS alias for the master (e.g. <code>master-2</code>, <code>master-3</code>, etc).</p>
-</li>
-</ul>
-</div>
-</li>
-</ol>
-</div>
-</div>
-<div class="sect3">
-<h4 id="perform-the-migration"><a class="link" href="#perform-the-migration">Perform the migration</a></h4>
-<div class="olist arabic">
-<ol class="arabic">
-<li>
-<p>Stop all the Kudu processes in the entire cluster.</p>
-</li>
-<li>
-<p>Format the data directory on each new master machine, and record the generated UUID. Use the
-following command sequence:</p>
-<div class="listingblock">
-<div class="content">
-<pre class="highlight"><code class="language-bash" data-lang="bash">$ sudo -u kudu kudu fs format --fs_wal_dir=<master_wal_dir> [--fs_data_dirs=<master_data_dirs>]
-$ sudo -u kudu kudu fs dump uuid --fs_wal_dir=<master_wal_dir> [--fs_data_dirs=<master_data_dirs>] 2>/dev/null</code></pre>
-</div>
-</div>
-<div class="dlist">
-<dl>
-<dt class="hdlist1">master_data_dir</dt>
-<dd>
-<p>new master’s previously recorded data directory</p>
-</dd>
-<dt class="hdlist1">Example</dt>
-<dd>
-<div class="listingblock">
-<div class="content">
-<pre>$ sudo -u kudu kudu fs format --fs_wal_dir=/data/kudu/master/wal --fs_data_dirs=/data/kudu/master/data
-$ sudo -u kudu kudu fs dump uuid --fs_wal_dir=/data/kudu/master/wal --fs_data_dirs=/data/kudu/master/data 2>/dev/null
-f5624e05f40649b79a757629a69d061e</pre>
-</div>
-</div>
-</dd>
-</dl>
-</div>
-</li>
-<li>
-<p>If using CM, add the new Kudu master roles now, but do not start them.</p>
-<div class="ulist">
-<ul>
-<li>
-<p>If using DNS aliases, override the empty value of the <code>Master Address</code> parameter for each role
-(including the existing master role) with that master’s alias.</p>
-</li>
-<li>
-<p>Add the port number (separated by a colon) if using a non-default RPC port value.</p>
-</li>
-</ul>
-</div>
-</li>
-<li>
-<p>Rewrite the master’s Raft configuration with the following command, executed on the existing
-master machine:</p>
-<div class="listingblock">
-<div class="content">
-<pre class="highlight"><code class="language-bash" data-lang="bash">$ sudo -u kudu kudu local_replica cmeta rewrite_raft_config --fs_wal_dir=<master_wal_dir> [--fs_data_dirs=<master_data_dirs>] <tablet_id> <all_masters></code></pre>
-</div>
-</div>
-<div class="dlist">
-<dl>
-<dt class="hdlist1">master_data_dir</dt>
-<dd>
-<p>existing master’s previously recorded data directory</p>
-</dd>
-<dt class="hdlist1">tablet_id</dt>
-<dd>
-<p>must be the string <code>00000000000000000000000000000000</code></p>
-</dd>
-<dt class="hdlist1">all_masters</dt>
-<dd>
-<p>space-separated list of masters, both new and existing. Each entry in the list must be
-a string of the form <code><uuid>:<hostname>:<port></code></p>
-<div class="dlist">
-<dl>
-<dt class="hdlist1">uuid</dt>
-<dd>
-<p>master’s previously recorded UUID</p>
-</dd>
-<dt class="hdlist1">hostname</dt>
-<dd>
-<p>master’s previously recorded hostname or alias</p>
-</dd>
-<dt class="hdlist1">port</dt>
-<dd>
-<p>master’s previously recorded RPC port number</p>
-</dd>
-</dl>
-</div>
-</dd>
-<dt class="hdlist1">Example</dt>
-<dd>
-<div class="listingblock">
-<div class="content">
-<pre>$ sudo -u kudu kudu local_replica cmeta rewrite_raft_config --fs_wal_dir=/data/kudu/master/wal --fs_data_dirs=/data/kudu/master/data 00000000000000000000000000000000 4aab798a69e94fab8d77069edff28ce0:master-1:7051 f5624e05f40649b79a757629a69d061e:master-2:7051 988d8ac6530f426cbe180be5ba52033d:master-3:7051</pre>
-</div>
-</div>
-</dd>
-</dl>
-</div>
-</li>
-<li>
-<p>Modify the value of the <code>master_addresses</code> configuration parameter for both existing master and new masters.
-The new value must be a comma-separated list of all of the masters. Each entry is a string of the form <code><hostname>:<port></code></p>
-<div class="dlist">
-<dl>
-<dt class="hdlist1">hostname</dt>
-<dd>
-<p>master’s previously recorded hostname or alias</p>
-</dd>
-<dt class="hdlist1">port</dt>
-<dd>
-<p>master’s previously recorded RPC port number</p>
-</dd>
-</dl>
-</div>
-</li>
-<li>
-<p>Start the existing master.</p>
-</li>
-<li>
-<p>Copy the master data to each new master with the following command, executed on each new master
-machine.</p>
-<div class="admonitionblock warning">
-<table>
-<tr>
-<td class="icon">
-<i class="fa icon-warning" title="Warning"></i>
-</td>
-<td class="content">
-If your Kudu cluster is secure, in addition to running as the Kudu UNIX user, you must
- authenticate as the Kudu service user prior to running this command.
-</td>
-</tr>
-</table>
-</div>
-<div class="listingblock">
-<div class="content">
-<pre class="highlight"><code class="language-bash" data-lang="bash">$ sudo -u kudu kudu local_replica copy_from_remote --fs_wal_dir=<master_wal_dir> [--fs_data_dirs=<master_data_dirs>] <tablet_id> <existing_master></code></pre>
-</div>
-</div>
-<div class="dlist">
-<dl>
-<dt class="hdlist1">master_data_dir</dt>
-<dd>
-<p>new master’s previously recorded data directory</p>
-</dd>
-<dt class="hdlist1">tablet_id</dt>
-<dd>
-<p>must be the string <code>00000000000000000000000000000000</code></p>
-</dd>
-<dt class="hdlist1">existing_master</dt>
-<dd>
-<p>RPC address of the existing master and must be a string of the form
-<code><hostname>:<port></code></p>
-<div class="dlist">
-<dl>
-<dt class="hdlist1">hostname</dt>
-<dd>
-<p>existing master’s previously recorded hostname or alias</p>
-</dd>
-<dt class="hdlist1">port</dt>
-<dd>
-<p>existing master’s previously recorded RPC port number</p>
-</dd>
-</dl>
-</div>
-</dd>
-<dt class="hdlist1">Example</dt>
-<dd>
-<div class="listingblock">
-<div class="content">
-<pre>$ sudo -u kudu kudu local_replica copy_from_remote --fs_wal_dir=/data/kudu/master/wal --fs_data_dirs=/data/kudu/master/data 00000000000000000000000000000000 master-1:7051</pre>
-</div>
-</div>
-</dd>
-</dl>
-</div>
-</li>
-<li>
-<p>Start all of the new masters.</p>
-<div class="admonitionblock warning">
-<table>
-<tr>
-<td class="icon">
-<i class="fa icon-warning" title="Warning"></i>
-</td>
-<td class="content">
-Skip the next step if using CM.
-</td>
-</tr>
-</table>
-</div>
-</li>
-<li>
-<p>Modify the value of the <code>tserver_master_addrs</code> configuration parameter for each tablet server.
-The new value must be a comma-separated list of masters where each entry is a string of the form
-<code><hostname>:<port></code></p>
-<div class="dlist">
-<dl>
-<dt class="hdlist1">hostname</dt>
-<dd>
-<p>master’s previously recorded hostname or alias</p>
-</dd>
-<dt class="hdlist1">port</dt>
-<dd>
-<p>master’s previously recorded RPC port number</p>
-</dd>
-</dl>
-</div>
-</li>
-<li>
-<p>Start all of the tablet servers.</p>
-</li>
-<li>
-<p>If you have Kudu tables that are accessed from Impala and you didn’t set up
-DNS aliases, update the HMS database manually in the underlying database that
-provides the storage for HMS.</p>
-<div class="ulist">
-<ul>
-<li>
-<p>The following is an example SQL statement you should run in the HMS database:</p>
-<div class="listingblock">
-<div class="content">
-<pre class="highlight"><code class="language-sql" data-lang="sql">UPDATE TABLE_PARAMS
-SET PARAM_VALUE =
- 'master-1.example.com,master-2.example.com,master-3.example.com'
-WHERE PARAM_KEY = 'kudu.master_addresses' AND PARAM_VALUE = 'old-master';</code></pre>
-</div>
-</div>
-</li>
-<li>
-<p>In <code>impala-shell</code>, run:</p>
-<div class="listingblock">
-<div class="content">
-<pre class="highlight"><code class="language-bash" data-lang="bash">INVALIDATE METADATA;</code></pre>
-</div>
-</div>
-<div class="paragraph">
-<p>==== Verify the migration was successful</p>
-</div>
-</li>
-</ul>
-</div>
-</li>
-</ol>
-</div>
-<div class="paragraph">
-<p>To verify that all masters are working properly, perform the following sanity checks:</p>
-</div>
-<div class="ulist">
-<ul>
-<li>
-<p>Using a browser, visit each master’s web UI. Look at the /masters page. All of the masters should
-be listed there with one master in the LEADER role and the others in the FOLLOWER role. The
-contents of /masters on each master should be the same.</p>
-</li>
-<li>
-<p>Run a Kudu system check (ksck) on the cluster using the <code>kudu</code> command line
-tool. See <a href="#ksck">Checking Cluster Health with <code>ksck</code></a> for more details.</p>
-</li>
-</ul>
-</div>
-</div>
-</div>
-<div class="sect2">
-<h3 id="_recovering_from_a_dead_kudu_master_in_a_multi_master_deployment"><a class="link" href="#_recovering_from_a_dead_kudu_master_in_a_multi_master_deployment">Recovering from a dead Kudu Master in a Multi-Master Deployment</a></h3>
-<div class="paragraph">
-<p>Kudu multi-master deployments function normally in the event of a master loss. However, it is
-important to replace the dead master; otherwise a second failure may lead to a loss of availability,
-depending on the number of available masters. This workflow describes how to replace the dead
-master.</p>
-</div>
-<div class="paragraph">
-<p>Due to <a href="https://issues.apache.org/jira/browse/KUDU-1620">KUDU-1620</a>, it is not possible to perform
-this workflow without also restarting the live masters. As such, the workflow requires a
-maintenance window, albeit a potentially brief one if the cluster was set up with DNS aliases.</p>
-</div>
-<div class="admonitionblock warning">
-<table>
-<tr>
-<td class="icon">
-<i class="fa icon-warning" title="Warning"></i>
-</td>
-<td class="content">
-Kudu does not yet support live Raft configuration changes for masters. As such, it is only
-possible to replace a master if the deployment was created with DNS aliases or if every node in the
-cluster is first shut down. See the <a href="#migrate_to_multi_master">multi-master migration workflow</a> for
-more details on deploying with DNS aliases.
-</td>
-</tr>
-</table>
-</div>
-<div class="admonitionblock warning">
-<table>
-<tr>
-<td class="icon">
-<i class="fa icon-warning" title="Warning"></i>
-</td>
-<td class="content">
-The workflow presupposes at least basic familiarity with Kudu configuration management. If
-using Cloudera Manager (CM), the workflow also presupposes familiarity with it.
-</td>
-</tr>
-</table>
-</div>
-<div class="admonitionblock warning">
-<table>
-<tr>
-<td class="icon">
-<i class="fa icon-warning" title="Warning"></i>
-</td>
-<td class="content">
-All of the command line steps below should be executed as the Kudu UNIX user, typically
-<code>kudu</code>.
-</td>
-</tr>
-</table>
-</div>
-<div class="sect3">
-<h4 id="_prepare_for_the_recovery"><a class="link" href="#_prepare_for_the_recovery">Prepare for the recovery</a></h4>
-<div class="olist arabic">
-<ol class="arabic">
-<li>
-<p>If the deployment was configured without DNS aliases perform the following steps:</p>
-<div class="ulist">
-<ul>
-<li>
-<p>Establish a maintenance window (one hour should be sufficient). During this time the Kudu cluster
-will be unavailable.</p>
-</li>
-<li>
-<p>Shut down all Kudu tablet server processes in the cluster.</p>
-</li>
-</ul>
-</div>
-</li>
-<li>
-<p>Ensure that the dead master is well and truly dead. Take whatever steps needed to prevent it from
-accidentally restarting; this can be quite dangerous for the cluster post-recovery.</p>
-</li>
-<li>
-<p>Choose one of the remaining live masters to serve as a basis for recovery. The rest of this
-workflow will refer to this master as the "reference" master.</p>
-</li>
-<li>
-<p>Choose an unused machine in the cluster where the new master will live. The master generates very
-little load so it can be colocated with other data services or load-generating processes, though
-not with another Kudu master from the same configuration. The rest of this workflow will refer to
-this master as the "replacement" master.</p>
-</li>
-<li>
-<p>Perform the following preparatory steps for the replacement master:</p>
-<div class="ulist">
-<ul>
-<li>
-<p>Ensure Kudu is installed on the machine, either via system packages (in which case the <code>kudu</code> and
-<code>kudu-master</code> packages should be installed), or via some other means.</p>
-</li>
-<li>
-<p>Choose and record the directory where the master’s data will live.</p>
-</li>
-</ul>
-</div>
-</li>
-<li>
-<p>Perform the following preparatory steps for each live master:</p>
-<div class="ulist">
-<ul>
-<li>
-<p>Identify and record the directory where the master’s data lives. If using Kudu system packages,
-the default value is /var/lib/kudu/master, but it may be customized via the <code>fs_wal_dir</code> and
-<code>fs_data_dirs</code> configuration parameters. Please note if you’ve set <code>fs_data_dirs</code> to some directories
-other than the value of <code>fs_wal_dir</code>, it should be explicitly included in every command below where
-<code>fs_wal_dir</code> is also included. For more information on configuring these directories, see the
-<a href="configuration.html#directory_configuration">Kudu Configuration docs</a>.</p>
-</li>
-<li>
-<p>Identify and record the master’s UUID. It can be fetched using the following command:</p>
-<div class="listingblock">
-<div class="content">
-<pre class="highlight"><code class="language-bash" data-lang="bash">$ sudo -u kudu kudu fs dump uuid --fs_wal_dir=<master_wal_dir> [--fs_data_dirs=<master_data_dirs>] 2>/dev/null</code></pre>
-</div>
-</div>
-<div class="dlist">
-<dl>
-<dt class="hdlist1">master_data_dir</dt>
-<dd>
-<p>live master’s previously recorded data directory</p>
-</dd>
-<dt class="hdlist1">Example</dt>
-<dd>
-<div class="listingblock">
-<div class="content">
-<pre>$ sudo -u kudu kudu fs dump uuid --fs_wal_dir=/data/kudu/master/wal --fs_data_dirs=/data/kudu/master/data 2>/dev/null
-80a82c4b8a9f4c819bab744927ad765c</pre>
-</div>
-</div>
-</dd>
-</dl>
-</div>
-</li>
-</ul>
-</div>
-</li>
-<li>
-<p>Perform the following preparatory steps for the reference master:</p>
-<div class="ulist">
-<ul>
-<li>
-<p>Identify and record the directory where the master’s data lives. If using Kudu system packages,
-the default value is /var/lib/kudu/master, but it may be customized via the <code>fs_wal_dir</code> and
-<code>fs_data_dirs</code> configuration parameters. Please note if you’ve set <code>fs_data_dirs</code> to some directories
-other than the value of <code>fs_wal_dir</code>, it should be explicitly included in every command below where
-<code>fs_wal_dir</code> is also included. For more information on configuring these directories, see the
-<a href="configuration.html#directory_configuration">Kudu Configuration docs</a>.</p>
-</li>
-<li>
-<p>Identify and record the UUIDs of every master in the cluster, using the following command:</p>
-<div class="listingblock">
-<div class="content">
-<pre class="highlight"><code class="language-bash" data-lang="bash">$ sudo -u kudu kudu local_replica cmeta print_replica_uuids --fs_wal_dir=<master_wal_dir> [--fs_data_dirs=<master_data_dirs>] <tablet_id> 2>/dev/null</code></pre>
-</div>
-</div>
-<div class="dlist">
-<dl>
-<dt class="hdlist1">master_data_dir</dt>
-<dd>
-<p>reference master’s previously recorded data directory</p>
-</dd>
-<dt class="hdlist1">tablet_id</dt>
-<dd>
-<p>must be the string <code>00000000000000000000000000000000</code></p>
-</dd>
-<dt class="hdlist1">Example</dt>
-<dd>
-<div class="listingblock">
-<div class="content">
-<pre>$ sudo -u kudu kudu local_replica cmeta print_replica_uuids --fs_wal_dir=/data/kudu/master/wal --fs_data_dirs=/data/kudu/master/data 00000000000000000000000000000000 2>/dev/null
-80a82c4b8a9f4c819bab744927ad765c 2a73eeee5d47413981d9a1c637cce170 1c3f3094256347528d02ec107466aef3</pre>
-</div>
-</div>
-</dd>
-</dl>
-</div>
-</li>
-</ul>
-</div>
-</li>
-<li>
-<p>Using the two previously-recorded lists of UUIDs (one for all live masters and one for all
-masters), determine and record (by process of elimination) the UUID of the dead master.</p>
-</li>
-</ol>
-</div>
-</div>
-<div class="sect3">
-<h4 id="_perform_the_recovery"><a class="link" href="#_perform_the_recovery">Perform the recovery</a></h4>
-<div class="olist arabic">
-<ol class="arabic">
-<li>
-<p>Format the data directory on the replacement master machine using the previously recorded
-UUID of the dead master. Use the following command sequence:</p>
-<div class="listingblock">
-<div class="content">
-<pre class="highlight"><code class="language-bash" data-lang="bash">$ sudo -u kudu kudu fs format --fs_wal_dir=<master_wal_dir> [--fs_data_dirs=<master_data_dirs>] --uuid=<uuid></code></pre>
-</div>
-</div>
-<div class="dlist">
-<dl>
-<dt class="hdlist1">master_data_dir</dt>
-<dd>
-<p>replacement master’s previously recorded data directory</p>
-</dd>
-<dt class="hdlist1">uuid</dt>
-<dd>
-<p>dead master’s previously recorded UUID</p>
-</dd>
-<dt class="hdlist1">Example</dt>
-<dd>
-<div class="listingblock">
-<div class="content">
-<pre>$ sudo -u kudu kudu fs format --fs_wal_dir=/data/kudu/master/wal --fs_data_dirs=/data/kudu/master/data --uuid=80a82c4b8a9f4c819bab744927ad765c</pre>
-</div>
-</div>
-</dd>
-</dl>
-</div>
-</li>
-<li>
-<p>Copy the master data to the replacement master with the following command:</p>
-<div class="admonitionblock warning">
-<table>
-<tr>
-<td class="icon">
-<i class="fa icon-warning" title="Warning"></i>
-</td>
-<td class="content">
-If your Kudu cluster is secure, in addition to running as the Kudu UNIX user, you must
- authenticate as the Kudu service user prior to running this command.
-</td>
-</tr>
-</table>
-</div>
-<div class="listingblock">
-<div class="content">
-<pre class="highlight"><code class="language-bash" data-lang="bash">$ sudo -u kudu kudu local_replica copy_from_remote --fs_wal_dir=<master_wal_dir> [--fs_data_dirs=<master_data_dirs>] <tablet_id> <reference_master></code></pre>
-</div>
-</div>
-<div class="dlist">
-<dl>
-<dt class="hdlist1">master_data_dir</dt>
-<dd>
-<p>replacement master’s previously recorded data directory</p>
-</dd>
-<dt class="hdlist1">tablet_id</dt>
-<dd>
-<p>must be the string <code>00000000000000000000000000000000</code></p>
-</dd>
-<dt class="hdlist1">reference_master</dt>
-<dd>
-<p>RPC address of the reference master and must be a string of the form
-<code><hostname>:<port></code></p>
-<div class="dlist">
-<dl>
-<dt class="hdlist1">hostname</dt>
-<dd>
-<p>reference master’s previously recorded hostname or alias</p>
-</dd>
-<dt class="hdlist1">port</dt>
-<dd>
-<p>reference master’s previously recorded RPC port number</p>
-</dd>
-</dl>
-</div>
-</dd>
-<dt class="hdlist1">Example</dt>
-<dd>
-<div class="listingblock">
-<div class="content">
-<pre>$ sudo -u kudu kudu local_replica copy_from_remote --fs_wal_dir=/data/kudu/master/wal --fs_data_dirs=/data/kudu/master/data 00000000000000000000000000000000 master-2:7051</pre>
-</div>
-</div>
-</dd>
-</dl>
-</div>
-</li>
-<li>
-<p>If using CM, add the replacement Kudu master role now, but do not start it.</p>
-<div class="ulist">
-<ul>
-<li>
-<p>Override the empty value of the <code>Master Address</code> parameter for the new role with the replacement
-master’s alias.</p>
-</li>
-<li>
-<p>Add the port number (separated by a colon) if using a non-default RPC port value.</p>
-</li>
-</ul>
-</div>
-</li>
-<li>
-<p>If the cluster was set up with DNS aliases, reconfigure the DNS alias for the dead master to point
-at the replacement master.</p>
-</li>
-<li>
-<p>If the cluster was set up without DNS aliases, perform the following steps:</p>
-<div class="ulist">
-<ul>
-<li>
-<p>Stop the remaining live masters.</p>
-</li>
-<li>
-<p>Rewrite the Raft configurations on these masters to include the replacement master. See Step 4 of
-<a href="#perform-the-migration">Perform the Migration</a> for more details.</p>
-</li>
-</ul>
-</div>
-</li>
-<li>
-<p>Start the replacement master.</p>
-</li>
-<li>
-<p>Restart the remaining masters in the new multi-master deployment. While the masters are shut down,
-there will be an availability outage, but it should last only as long as it takes for the masters
-to come back up.</p>
-</li>
-</ol>
-</div>
-<div class="paragraph">
-<p>Congratulations, the dead master has been replaced! To verify that all masters are working properly,
-consider performing the following sanity checks:</p>
-</div>
-<div class="ulist">
-<ul>
-<li>
-<p>Using a browser, visit each master’s web UI. Look at the /masters page. All of the masters should
-be listed there with one master in the LEADER role and the others in the FOLLOWER role. The
-contents of /masters on each master should be the same.</p>
-</li>
-<li>
-<p>Run a Kudu system check (ksck) on the cluster using the <code>kudu</code> command line
-tool. See <a href="#ksck">Checking Cluster Health with <code>ksck</code></a> for more details.</p>
-</li>
-</ul>
-</div>
-</div>
-</div>
-<div class="sect2">
-<h3 id="_removing_kudu_masters_from_a_multi_master_deployment"><a class="link" href="#_removing_kudu_masters_from_a_multi_master_deployment">Removing Kudu Masters from a Multi-Master Deployment</a></h3>
-<div class="paragraph">
-<p>In the event that a multi-master deployment has been overallocated nodes, the following steps should
-be taken to remove the unwanted masters.</p>
-</div>
-<div class="admonitionblock warning">
-<table>
-<tr>
-<td class="icon">
-<i class="fa icon-warning" title="Warning"></i>
-</td>
-<td class="content">
-In planning the new multi-master configuration, keep in mind that the number of masters
-should be odd and that three or five node master configurations are recommended.
-</td>
-</tr>
-</table>
-</div>
-<div class="admonitionblock warning">
-<table>
-<tr>
-<td class="icon">
-<i class="fa icon-warning" title="Warning"></i>
-</td>
-<td class="content">
-Dropping the number of masters below the number of masters currently needed for a Raft
-majority can incur data loss. To mitigate this, ensure that the leader master is not removed during
-this process.
-</td>
-</tr>
-</table>
-</div>
-<div class="sect3">
-<h4 id="_prepare_for_the_removal"><a class="link" href="#_prepare_for_the_removal">Prepare for the removal</a></h4>
-<div class="olist arabic">
-<ol class="arabic">
-<li>
-<p>Establish a maintenance window (one hour should be sufficient). During this time the Kudu cluster
-will be unavailable.</p>
-</li>
-<li>
-<p>Identify the UUID and RPC address current leader of the multi-master deployment by visiting the
-<code>/masters</code> page of any master’s web UI. This master must not be removed during this process; its
-removal may result in severe data loss.</p>
-</li>
-<li>
-<p>Stop all the Kudu processes in the entire cluster.</p>
-</li>
-<li>
-<p>If using CM, remove the unwanted Kudu master.</p>
-</li>
-</ol>
-</div>
-</div>
-<div class="sect3">
-<h4 id="_perform_the_removal"><a class="link" href="#_perform_the_removal">Perform the removal</a></h4>
-<div class="olist arabic">
-<ol class="arabic">
-<li>
-<p>Rewrite the Raft configuration on the remaining masters to include only the remaining masters. See
-Step 4 of <a href="#perform-the-migration">Perform the Migration</a> for more details.</p>
-</li>
-<li>
-<p>Remove the data directories and WAL directory on the unwanted masters. This is a precaution to
-ensure that they cannot start up again and interfere with the new multi-master deployment.</p>
-</li>
-<li>
-<p>Modify the value of the <code>master_addresses</code> configuration parameter for the masters of the new
-multi-master deployment. If migrating to a single-master deployment, the <code>master_addresses</code> flag
-should be omitted entirely.</p>
-</li>
-<li>
-<p>Start all of the masters that were not removed.</p>
-</li>
-<li>
-<p>Modify the value of the <code>tserver_master_addrs</code> configuration parameter for the tablet servers to
-remove any unwanted masters.</p>
-</li>
-<li>
-<p>Start all of the tablet servers.</p>
-</li>
-</ol>
-</div>
-</div>
-<div class="sect3">
-<h4 id="_verify_the_migration_was_successful"><a class="link" href="#_verify_the_migration_was_successful">Verify the migration was successful</a></h4>
-<div class="paragraph">
-<p>To verify that all masters are working properly, perform the following sanity checks:</p>
-</div>
-<div class="ulist">
-<ul>
-<li>
-<p>Using a browser, visit each master’s web UI. Look at the /masters page. All of the masters should
-be listed there with one master in the LEADER role and the others in the FOLLOWER role. The
-contents of /masters on each master should be the same.</p>
-</li>
-<li>
-<p>Run a Kudu system check (ksck) on the cluster using the <code>kudu</code> command line
-tool. See <a href="#ksck">Checking Cluster Health with <code>ksck</code></a> for more details.</p>
-</li>
-</ul>
-</div>
-</div>
-</div>
-<div class="sect2">
-<h3 id="ksck"><a class="link" href="#ksck">Checking Cluster Health with <code>ksck</code></a></h3>
-<div class="paragraph">
-<p>The <code>kudu</code> CLI includes a tool named <code>ksck</code> which can be used for checking
-cluster health and data integrity. <code>ksck</code> will identify issues such as
-under-replicated tablets, unreachable tablet servers, or tablets without a
-leader.</p>
-</div>
-<div class="paragraph">
-<p><code>ksck</code> should be run from the command line, and requires the full list of master
-addresses to be specified:</p>
-</div>
-<div class="listingblock">
-<div class="content">
-<pre class="highlight"><code class="language-bash" data-lang="bash">$ sudo -u kudu kudu cluster ksck master-01.example.com,master-02.example.com,master-03.example.com</code></pre>
-</div>
-</div>
-<div class="paragraph">
-<p>To see a full list of the options available with <code>ksck</code>, use the <code>--help</code> flag.
-If the cluster is healthy, <code>ksck</code> will print a success message, and return a
-zero (success) exit status.</p>
-</div>
-<div class="listingblock">
-<div class="content">
-<pre>Connected to the Master
-Fetched info from all 1 Tablet Servers
-Table IntegrationTestBigLinkedList is HEALTHY (1 tablet(s) checked)
-
-The metadata for 1 table(s) is HEALTHY
-OK</pre>
-</div>
-</div>
-<div class="paragraph">
-<p>If the cluster is unhealthy, for instance if a tablet server process has
-stopped, <code>ksck</code> will report the issue(s) and return a non-zero exit status:</p>
-</div>
-<div class="listingblock">
-<div class="content">
-<pre>Connected to the Master
-WARNING: Unable to connect to Tablet Server 8a0b66a756014def82760a09946d1fce
-(tserver-01.example.com:7050): Network error: could not send Ping RPC to server: Client connection negotiation failed: client connection to 192.168.0.2:7050: connect: Connection refused (error 61)
-WARNING: Fetched info from 0 Tablet Servers, 1 weren't reachable
-Tablet ce3c2d27010d4253949a989b9d9bf43c of table 'IntegrationTestBigLinkedList'
-is unavailable: 1 replica(s) not RUNNING
- 8a0b66a756014def82760a09946d1fce (tserver-01.example.com:7050): TS unavailable [LEADER]
-
- Table IntegrationTestBigLinkedList has 1 unavailable tablet(s)
-
- WARNING: 1 out of 1 table(s) are not in a healthy state
- ==================
- Errors:
- ==================
- error fetching info from tablet servers: Network error: Not all Tablet Servers are reachable
- table consistency check error: Corruption: 1 table(s) are bad
-
- FAILED
- Runtime error: ksck discovered errors</pre>
-</div>
-</div>
-<div class="paragraph">
-<p>To verify data integrity, the optional <code>--checksum_scan</code> flag can be set, which
-will ensure the cluster has consistent data by scanning each tablet replica and
-comparing results. The <code>--tables</code> or <code>--tablets</code> flags can be used to limit the
-scope of the checksum scan to specific tables or tablets, respectively. For
-example, checking data integrity on the <code>IntegrationTestBigLinkedList</code> table can
-be done with the following command:</p>
-</div>
-<div class="listingblock">
-<div class="content">
-<pre class="highlight"><code class="language-bash" data-lang="bash">$ sudo -u kudu kudu cluster ksck --checksum_scan --tables IntegrationTestBigLinkedList master-01.example.com,master-02.example.com,master-03.example.com</code></pre>
-</div>
-</div>
-</div>
-<div class="sect2">
-<h3 id="change_dir_config"><a class="link" href="#change_dir_config">Changing Directory Configurations</a></h3>
-<div class="paragraph">
-<p>For higher read parallelism and larger volumes of storage per server, users may
-want to configure servers to store data in multiple directories on different
-devices. Once a server is started, users must go through the following steps
-to change the directory configuration.</p>
-</div>
-<div class="paragraph">
-<p>Users can add or remove data directories to an existing master or tablet server
-via the <code>kudu fs update_dirs</code> tool. Data is striped across data directories,
-and when a new data directory is added, new data will be striped across the
-union of the old and new directories.</p>
-</div>
-<div class="admonitionblock note">
-<table>
-<tr>
-<td class="icon">
-<i class="fa icon-note" title="Note"></i>
-</td>
-<td class="content">
-Unless the <code>--force</code> flag is specified, Kudu will not allow for the
-removal of a directory across which tablets are configured to spread data. If
-<code>--force</code> is specified, all tablets configured to use that directory will fail
-upon starting up and be replicated elsewhere.
-</td>
-</tr>
-</table>
-</div>
-<div class="admonitionblock note">
-<table>
-<tr>
-<td class="icon">
-<i class="fa icon-note" title="Note"></i>
-</td>
-<td class="content">
-If the <a href="configuration.html$directory_configuration">metadata
-directory</a> overlaps with a data directory, as was the default prior to Kudu
-1.7, or if a non-default metadata directory is configured, the
-<code>--fs_metadata_dir</code> configuration must be specified when running the <code>kudu fs
-update_dirs</code> tool.
-</td>
-</tr>
-</table>
-</div>
-<div class="admonitionblock note">
-<table>
-<tr>
-<td class="icon">
-<i class="fa icon-note" title="Note"></i>
-</td>
-<td class="content">
-Only new tablet replicas (i.e. brand new tablets' replicas and replicas
-that are copied to the server for high availability) will use the new
-directory. Existing tablet replicas on the server will not be rebalanced across
-the new directory.
-</td>
-</tr>
-</table>
-</div>
-<div class="admonitionblock warning">
-<table>
-<tr>
-<td class="icon">
-<i class="fa icon-warning" title="Warning"></i>
-</td>
-<td class="content">
-All of the command line steps below should be executed as the Kudu
-UNIX user, typically <code>kudu</code>.
-</td>
-</tr>
-</table>
-</div>
-<div class="olist arabic">
-<ol class="arabic">
-<li>
-<p>The tool can only run while the server is offline, so establish a maintenance
-window to update the server. The tool itself runs quickly, so this offline
-window should be brief, and as such, only the server to update needs to be
-offline. However, if the server is offline for too long (see the
-<code>follower_unavailable_considered_failed_sec</code> flag), the tablet replicas on it
-may be evicted from their Raft groups. To avoid this, it may be desirable to
-bring the entire cluster offline while performing the update.</p>
-</li>
-<li>
-<p>Run the tool with the desired directory configuration flags. For example, if a
-cluster was set up with <code>--fs_wal_dir=/wals</code>, <code>--fs_metadata_dir=/meta</code>, and
-<code>--fs_data_dirs=/data/1,/data/2,/data/3</code>, and <code>/data/3</code> is to be removed (e.g.
-due to a disk error), run the command:</p>
-<div class="listingblock">
-<div class="content">
-<pre class="highlight"><code class="language-bash" data-lang="bash">$ sudo -u kudu kudu fs update_dirs --force --fs_wal_dir=/wals --fs_metadata_dir=/meta --fs_data_dirs=/data/1,/data/2</code></pre>
-</div>
-</div>
-</li>
-<li>
-<p>Modify the values of the <code>fs_data_dirs</code> flags for the updated sever. If using
-CM, make sure to only update the configurations of the updated server, rather
-than of the entire Kudu service.</p>
-</li>
-<li>
-<p>Once complete, the server process can be started. When Kudu is installed using
-system packages, <code>service</code> is typically used:</p>
-<div class="listingblock">
-<div class="content">
-<pre class="highlight"><code class="language-bash" data-lang="bash">$ sudo service kudu-tserver start</code></pre>
-</div>
-</div>
-</li>
-</ol>
-</div>
-</div>
-<div class="sect2">
-<h3 id="disk_failure_recovery"><a class="link" href="#disk_failure_recovery">Recovering from Disk Failure</a></h3>
-<div class="paragraph">
-<p>Kudu nodes can only survive failures of disks on which certain Kudu directories
-are mounted. For more information about the different Kudu directory types, see
-the section on <a href="configuration.html#directory_configuration">Kudu Directory
-Configurations</a>. Below describes this behavior across different Apache Kudu
-releases.</p>
-</div>
-<table id="disk_failure_behavior" class="tableblock frame-all grid-all spread">
-<caption class="title">Table 1. Kudu Disk Failure Behavior</caption>
-<colgroup>
-<col style="width: 33.3333%;">
-<col style="width: 33.3333%;">
-<col style="width: 33.3334%;">
-</colgroup>
-<thead>
-<tr>
-<th class="tableblock halign-left valign-top">Node Type</th>
-<th class="tableblock halign-left valign-top">Kudu Directory Type</th>
-<th class="tableblock halign-left valign-top">Kudu Releases that Crash on Disk Failure</th>
-</tr>
-</thead>
-<tbody>
-<tr>
-<td class="tableblock halign-left valign-top"><p class="tableblock">Master</p></td>
-<td class="tableblock halign-left valign-top"><p class="tableblock">All</p></td>
-<td class="tableblock halign-left valign-top"><p class="tableblock">All</p></td>
-</tr>
-<tr>
-<td class="tableblock halign-left valign-top"><p class="tableblock">Tablet Server</p></td>
-<td class="tableblock halign-left valign-top"><p class="tableblock">Directory containing WALs</p></td>
-<td class="tableblock halign-left valign-top"><p class="tableblock">All</p></td>
-</tr>
-<tr>
-<td class="tableblock halign-left valign-top"><p class="tableblock">Tablet Server</p></td>
-<td class="tableblock halign-left valign-top"><p class="tableblock">Directory containing tablet metadata</p></td>
-<td class="tableblock halign-left valign-top"><p class="tableblock">All</p></td>
-</tr>
-<tr>
-<td class="tableblock halign-left valign-top"><p class="tableblock">Tablet Server</p></td>
-<td class="tableblock halign-left valign-top"><p class="tableblock">Directory containing data blocks only</p></td>
-<td class="tableblock halign-left valign-top"><p class="tableblock">Pre-1.6.0</p></td>
-</tr>
-</tbody>
-</table>
-<div class="paragraph">
-<p>When a disk failure occurs that does not lead to a crash, Kudu will stop using
-the affected directory, shut down tablets with blocks on the affected
-directories, and automatically re-replicate the affected tablets to other
-tablet servers. The affected server will remain alive and print messages to the
-log indicating the disk failure, for example:</p>
-</div>
-<div class="listingblock">
-<div class="content">
-<pre>E1205 19:06:24.163748 27115 data_dirs.cc:1011] Directory /data/8/kudu/data marked as failed
-E1205 19:06:30.324795 27064 log_block_manager.cc:1822] Not using report from /data/8/kudu/data: IO error: Could not open container 0a6283cab82d4e75848f49772d2638fe: /data/8/kudu/data/0a6283cab82d4e75848f49772d2638fe.metadata: Read-only file system (error 30)
-E1205 19:06:33.564638 27220 ts_tablet_manager.cc:946] T 4957808439314e0d97795c1394348d80 P 70f7ee61ead54b1885d819f354eb3405: aborting tablet bootstrap: tablet has data in a failed directory</pre>
-</div>
-</div>
-<div class="paragraph">
-<p>While in this state, the affected node will avoid using the failed disk,
-leading to lower storage volume and reduced read parallelism. The administrator
-should schedule a brief window to <a href="#change_dir_config">update the node’s
-directory configuration</a> to exclude the failed disk.</p>
-</div>
-</div>
-<div class="sect2">
-<h3 id="tablet_majority_down_recovery"><a class="link" href="#tablet_majority_down_recovery">Bringing a tablet that has lost a majority of replicas back online</a></h3>
-<div class="paragraph">
-<p>If a tablet has permanently lost a majority of its replicas, it cannot recover
-automatically and operator intervention is required. The steps below may cause
-recent edits to the tablet to be lost, potentially resulting in permanent data
-loss. Only attempt the procedure below if it is impossible to bring
-a majority back online.</p>
-</div>
-<div class="paragraph">
-<p>Suppose a tablet has lost a majority of its replicas. The first step in
-diagnosing and fixing the problem is to examine the tablet’s state using ksck:</p>
-</div>
-<div class="listingblock">
-<div class="content">
-<pre class="highlight"><code class="language-bash" data-lang="bash">$ sudo -u kudu kudu cluster ksck --tablets=e822cab6c0584bc0858219d1539a17e6 master-00,master-01,master-02
-Connected to the Master
-Fetched info from all 5 Tablet Servers
-Tablet e822cab6c0584bc0858219d1539a17e6 of table 'my_table' is unavailable: 2 replica(s) not RUNNING
- 638a20403e3e4ae3b55d4d07d920e6de (tserver-00:7150): RUNNING
- 9a56fa85a38a4edc99c6229cba68aeaa (tserver-01:7150): bad state
- State: FAILED
- Data state: TABLET_DATA_READY
- Last status: <failure message>
- c311fef7708a4cf9bb11a3e4cbcaab8c (tserver-02:7150): bad state
- State: FAILED
- Data state: TABLET_DATA_READY
- Last status: <failure message></code></pre>
-</div>
-</div>
-<div class="paragraph">
-<p>This output shows that, for tablet <code>e822cab6c0584bc0858219d1539a17e6</code>, the two
-tablet replicas on <code>tserver-01</code> and <code>tserver-02</code> failed. The remaining replica
-is not the leader, so the leader replica failed as well. This means the chance
-of data loss is higher since the remaining replica on <code>tserver-00</code> may have
-been lagging. In general, to accept the potential data loss and restore the
-tablet from the remaining replicas, divide the tablet replicas into two groups:</p>
-</div>
-<div class="olist arabic">
-<ol class="arabic">
-<li>
-<p>Healthy replicas: Those in <code>RUNNING</code> state as reported by ksck</p>
-</li>
-<li>
-<p>Unhealthy replicas</p>
-</li>
-</ol>
-</div>
-<div class="paragraph">
-<p>For example, in the above ksck output, the replica on tablet server <code>tserver-00</code>
-is healthy, while the replicas on <code>tserver-01</code> and <code>tserver-02</code> are unhealthy.
-On each tablet server with a healthy replica, alter the consensus configuration
-to remove unhealthy replicas. In the typical case of 1 out of 3 surviving
-replicas, there will be only one healthy replica, so the consensus configuration
-will be rewritten to include only the healthy replica.</p>
-</div>
-<div class="listingblock">
-<div class="content">
-<pre class="highlight"><code class="language-bash" data-lang="bash">$ sudo -u kudu kudu remote_replica unsafe_change_config tserver-00:7150 <tablet-id> <tserver-00-uuid></code></pre>
-</div>
-</div>
-<div class="paragraph">
-<p>where <code><tablet-id></code> is <code>e822cab6c0584bc0858219d1539a17e6</code> and
-<code><tserver-00-uuid></code> is the uuid of <code>tserver-00</code>,
-<code>638a20403e3e4ae3b55d4d07d920e6de</code>.</p>
-</div>
-<div class="paragraph">
-<p>Once the healthy replicas' consensus configurations have been forced to exclude
-the unhealthy replicas, the healthy replicas will be able to elect a leader.
-The tablet will become available for writes, though it will still be
-under-replicated. Shortly after the tablet becomes available, the leader master
-will notice that it is under-replicated, and will cause the tablet to
-re-replicate until the proper replication factor is restored. The unhealthy
-replicas will be tombstoned by the master, causing their remaining data to be
-deleted.</p>
-</div>
-<div class="sect3">
-<h4 id="rebuilding_kudu"><a class="link" href="#rebuilding_kudu">Rebuilding a Kudu Filesystem Layout</a></h4>
-<div class="paragraph">
-<p>In the event that critical files are lost, i.e. WALs or tablet-specific
-metadata, all Kudu directories on the server must be deleted and rebuilt to
-ensure correctness. Doing so will destroy the copy of the data for each tablet
-replica hosted on the local server. Kudu will automatically re-replicate tablet
-replicas removed in this way, provided the replication factor is at least three
-and all other servers are online and healthy.</p>
-</div>
-<div class="admonitionblock note">
-<table>
-<tr>
-<td class="icon">
-<i class="fa icon-note" title="Note"></i>
-</td>
-<td class="content">
-These steps use a tablet server as an example, but the steps are the same
-for Kudu master servers.
-</td>
-</tr>
-</table>
-</div>
-<div class="admonitionblock warning">
-<table>
-<tr>
-<td class="icon">
-<i class="fa icon-warning" title="Warning"></i>
-</td>
-<td class="content">
-If multiple nodes need their FS layouts rebuilt, wait until all
-replicas previously hosted on each node have finished automatically
-re-replicating elsewhere before continuing. Failure to do so can result in
-permanent data loss.
-</td>
-</tr>
-</table>
-</div>
-<div class="admonitionblock warning">
-<table>
-<tr>
-<td class="icon">
-<i class="fa icon-warning" title="Warning"></i>
-</td>
-<td class="content">
-Before proceeding, ensure the contents of the directories are backed
-up, either as a copy or in the form of other tablet replicas.
-</td>
-</tr>
-</table>
-</div>
-<div class="olist arabic">
-<ol class="arabic">
-<li>
-<p>The first step to rebuilding a server with a new directory configuration is
-emptying all of the server’s existing directories. For example, if a tablet
-server is configured with <code>--fs_wal_dir=/data/0/kudu-tserver-wal</code>,
-<code>--fs_metadata_dir=/data/0/kudu-tserver-meta</code>, and
-<code>--fs_data_dirs=/data/1/kudu-tserver,/data/2/kudu-tserver</code>, the following
-commands will remove the WAL directory’s and data directories' contents:</p>
-<div class="listingblock">
-<div class="content">
-<pre class="highlight"><code class="language-bash" data-lang="bash"># Note: this will delete all of the data from the local tablet server.
-$ rm -rf /data/0/kudu-tserver-wal/* /data/0/kudu-tserver-meta/* /data/1/kudu-tserver/* /data/2/kudu-tserver/*</code></pre>
-</div>
-</div>
-</li>
-<li>
-<p>If using CM, update the configurations for the rebuilt server to include only
-the desired directories. Make sure to only update the configurations of servers
-to which changes were applied, rather than of the entire Kudu service.</p>
-</li>
-<li>
-<p>After directories are deleted, the server process can be started with the new
-directory configuration. The appropriate sub-directories will be created by
-Kudu upon starting up.</p>
-</li>
-</ol>
-</div>
-</div>
-</div>
-</div>
-</div>
- </div>
- <div class="col-md-3">
-
- <div id="toc" data-spy="affix" data-offset-top="70">
- <ul>
-
- <li>
-
- <a href="index.html">Introducing Kudu</a>
- </li>
- <li>
-
- <a href="release_notes.html">Kudu Release Notes</a>
- </li>
- <li>
-
- <a href="quickstart.html">Getting Started with Kudu</a>
- </li>
- <li>
-
- <a href="installation.html">Installation Guide</a>
- </li>
- <li>
-
- <a href="configuration.html">Configuring Kudu</a>
- </li>
- <li>
-
- <a href="kudu_impala_integration.html">Using Impala with Kudu</a>
- </li>
- <li>
-<span class="active-toc">Administering Kudu</span>
- <ul class="sectlevel1">
-<li><a href="#_starting_and_stopping_kudu_processes">Starting and Stopping Kudu Processes</a></li>
-<li><a href="#_kudu_web_interfaces">Kudu Web Interfaces</a>
-<ul class="sectlevel2">
-<li><a href="#_kudu_master_web_interface">Kudu Master Web Interface</a></li>
-<li><a href="#_kudu_tablet_server_web_interface">Kudu Tablet Server Web Interface</a></li>
-<li><a href="#_common_web_interface_pages">Common Web Interface Pages</a></li>
-</ul>
-</li>
-<li><a href="#_kudu_metrics">Kudu Metrics</a>
-<ul class="sectlevel2">
-<li><a href="#_listing_available_metrics">Listing available metrics</a></li>
-<li><a href="#_collecting_metrics_via_http">Collecting metrics via HTTP</a></li>
-<li><a href="#_diagnostics_logging">Diagnostics Logging</a></li>
-</ul>
-</li>
-<li><a href="#_common_kudu_workflows">Common Kudu workflows</a>
-<ul class="sectlevel2">
-<li><a href="#migrate_to_multi_master">Migrating to Multiple Kudu Masters</a>
-<ul class="sectlevel3">
-<li><a href="#_prepare_for_the_migration">Prepare for the migration</a></li>
-<li><a href="#perform-the-migration">Perform the migration</a></li>
-</ul>
-</li>
-<li><a href="#_recovering_from_a_dead_kudu_master_in_a_multi_master_deployment">Recovering from a dead Kudu Master in a Multi-Master Deployment</a>
-<ul class="sectlevel3">
-<li><a href="#_prepare_for_the_recovery">Prepare for the recovery</a></li>
-<li><a href="#_perform_the_recovery">Perform the recovery</a></li>
-</ul>
-</li>
-<li><a href="#_removing_kudu_masters_from_a_multi_master_deployment">Removing Kudu Masters from a Multi-Master Deployment</a>
-<ul class="sectlevel3">
-<li><a href="#_prepare_for_the_removal">Prepare for the removal</a></li>
-<li><a href="#_perform_the_removal">Perform the removal</a></li>
-<li><a href="#_verify_the_migration_was_successful">Verify the migration was successful</a></li>
-</ul>
-</li>
-<li><a href="#ksck">Checking Cluster Health with <code>ksck</code></a></li>
-<li><a href="#change_dir_config">Changing Directory Configurations</a></li>
-<li><a href="#disk_failure_recovery">Recovering from Disk Failure</a></li>
-<li><a href="#tablet_majority_down_recovery">Bringing a tablet that has lost a majority of replicas back online</a>
-<ul class="sectlevel3">
-<li><a href="#rebuilding_kudu">Rebuilding a Kudu Filesystem Layout</a></li>
-</ul>
-</li>
-</ul>
-</li>
-</ul>
- </li>
- <li>
-
- <a href="troubleshooting.html">Troubleshooting Kudu</a>
- </li>
- <li>
-
- <a href="developing.html">Developing Applications with Kudu</a>
- </li>
- <li>
-
- <a href="schema_design.html">Kudu Schema Design</a>
- </li>
- <li>
-
- <a href="security.html">Kudu Security</a>
- </li>
- <li>
-
- <a href="transaction_semantics.html">Kudu Transaction Semantics</a>
- </li>
- <li>
-
- <a href="background_tasks.html">Background Maintenance Tasks</a>
- </li>
- <li>
-
- <a href="configuration_reference.html">Kudu Configuration Reference</a>
- </li>
- <li>
-
- <a href="command_line_tools_reference.html">Kudu Command Line Tools Reference</a>
- </li>
- <li>
-
- <a href="known_issues.html">Known Issues and Limitations</a>
- </li>
- <li>
-
- <a href="contributing.html">Contributing to Kudu</a>
- </li>
- <li>
-
- <a href="export_control.html">Export Control Notice</a>
- </li>
- </ul>
- </div>
- </div>
- </div>
-</div>
\ No newline at end of file
diff --git a/docs/background_tasks.html b/docs/background_tasks.html
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--- a/docs/background_tasks.html
+++ /dev/null
@@ -1,223 +0,0 @@
----
-title: Apache Kudu Background Maintenance Tasks
-layout: default
-active_nav: docs
-last_updated: 'Last updated 2018-06-14 08:17:56 PDT'
----
-<!--
-
-Licensed under the Apache License, Version 2.0 (the "License");
-you may not use this file except in compliance with the License.
-You may obtain a copy of the License at
-
- http://www.apache.org/licenses/LICENSE-2.0
-
-Unless required by applicable law or agreed to in writing, software
-distributed under the License is distributed on an "AS IS" BASIS,
-WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-See the License for the specific language governing permissions and
-limitations under the License.
--->
-
-
-<div class="container">
- <div class="row">
- <div class="col-md-9">
-
-<h1>Apache Kudu Background Maintenance Tasks</h1>
- <div id="preamble">
-<div class="sectionbody">
-<div class="paragraph">
-<p>Kudu relies on running background tasks for many important automatic
-maintenance activities. These tasks include flushing data from memory to disk,
-compacting data to improve performance, freeing up disk space, and more.</p>
-</div>
-</div>
-</div>
-<div class="sect1">
-<h2 id="_maintenance_manager"><a class="link" href="#_maintenance_manager">Maintenance manager</a></h2>
-<div class="sectionbody">
-<div class="paragraph">
-<p>The maintenance manager schedules and runs background tasks. At any given point
-in time, the maintenance manager is prioritizing the next task based on the
-improvement needed at that moment, such as relieving memory pressure, improving
-read performance, or freeing up disk space. The number of worker threads
-dedicated to running background tasks can be controlled by setting
-<code>--maintenance_manager_num_threads</code>.</p>
-</div>
-</div>
-</div>
-<div class="sect1">
-<h2 id="_flushing_data_to_disk"><a class="link" href="#_flushing_data_to_disk">Flushing data to disk</a></h2>
-<div class="sectionbody">
-<div class="paragraph">
-<p>Flushing data from memory to disk relieves memory pressure and can improve read
-performance by switching from a write-optimized, row-oriented in-memory format
-in the <code>MemRowSet</code> to a read-optimized, column-oriented format on disk.
-Background tasks that flush data include <code>FlushMRSOp</code> and
-<code>FlushDeltaMemStoresOp</code>.</p>
-</div>
-<div class="paragraph">
-<p>The metrics associated with these ops have the prefix <code>flush_mrs</code> and
-<code>flush_dms</code>, respectively.</p>
-</div>
-</div>
-</div>
-<div class="sect1">
-<h2 id="_compacting_on_disk_data"><a class="link" href="#_compacting_on_disk_data">Compacting on-disk data</a></h2>
-<div class="sectionbody">
-<div class="paragraph">
-<p>Kudu constantly performs several types of compaction tasks in order to maintain
-consistent read and write performance over time. A merging compaction, which combines
-multiple <code>DiskRowSets</code> together into a single <code>DiskRowSet</code>, is run by
-<code>CompactRowSetsOp</code>. There are two types of delta store compaction operations
-that may be run as well: <code>MinorDeltaCompactionOp</code> and <code>MajorDeltaCompactionOp</code>.</p>
-</div>
-<div class="paragraph">
-<p>For more information on what these different types of compaction operations do,
-please see the
-<a href="https://github.com/apache/kudu/blob/master/docs/design-docs/tablet.md">Kudu Tablet
-design document</a>.</p>
-</div>
-<div class="paragraph">
-<p>The metrics associated with these tasks have the prefix <code>compact_rs</code>,
-<code>delta_minor_compact_rs</code>, and <code>delta_major_compact_rs</code>, respectively.</p>
-</div>
-</div>
-</div>
-<div class="sect1">
-<h2 id="_write_ahead_log_gc"><a class="link" href="#_write_ahead_log_gc">Write-ahead log GC</a></h2>
-<div class="sectionbody">
-<div class="paragraph">
-<p>Kudu maintains a write-ahead log (WAL) per tablet that is split into discrete
-fixed-size segments. A tablet periodically rolls the WAL to a new log segment
-when the active segment reaches a configured size (controlled by
-<code>--log_segment_size_mb</code>). In order to save disk space and decrease startup
-time, a background task called <code>LogGCOp</code> attempts to garbage-collect (GC) old
-WAL segments by deleting them from disk once it is determined that they are no
-longer needed by the local node for durability.</p>
-</div>
-<div class="paragraph">
-<p>The metrics associated with this background task have the prefix <code>log_gc</code>.</p>
-</div>
-</div>
-</div>
-<div class="sect1">
-<h2 id="_tablet_history_gc_and_the_ancient_history_mark"><a class="link" href="#_tablet_history_gc_and_the_ancient_history_mark">Tablet history GC and the ancient history mark</a></h2>
-<div class="sectionbody">
-<div class="paragraph">
-<p>Because Kudu uses a multiversion concurrency control (MVCC) mechanism to
-ensure that snapshot scans can proceeed isolated from new changes to a table,
-periodically old historical data should be garbage-collected (removed) to free
-up disk space. While Kudu never removes rows or data that are visible in the
-latest version of the data, Kudu does remove records of old changes that are no
-longer visible.</p>
-</div>
-<div class="paragraph">
-<p>The point in time in the past beyond which historical MVCC data becomes
-inaccessible and is free to be deleted is called the <em>ancient history mark</em>
-(AHM). The AHM can be configured by setting <code>--tablet_history_max_age_sec</code>.</p>
-</div>
-<div class="paragraph">
-<p>There are two background tasks that GC historical MVCC data older than the AHM:
-the one that runs the merging compaction, called <code>CompactRowSetsOp</code> (see
-above), and a separate background task that deletes old undo delta blocks,
-called <code>UndoDeltaBlockGCOp</code>. Running <code>UndoDeltaBlockGCOp</code> reduces disk space
-usage in all workloads, but particularly in those with a higher volume of
-updates or upserts.</p>
-</div>
-<div class="paragraph">
-<p>The metrics associated with this background task have the prefix
-<code>undo_delta_block</code>.</p>
-</div>
-</div>
-</div>
- </div>
- <div class="col-md-3">
-
- <div id="toc" data-spy="affix" data-offset-top="70">
- <ul>
-
- <li>
-
- <a href="index.html">Introducing Kudu</a>
- </li>
- <li>
-
- <a href="release_notes.html">Kudu Release Notes</a>
- </li>
- <li>
-
- <a href="quickstart.html">Getting Started with Kudu</a>
- </li>
- <li>
-
- <a href="installation.html">Installation Guide</a>
- </li>
- <li>
-
- <a href="configuration.html">Configuring Kudu</a>
- </li>
- <li>
-
- <a href="kudu_impala_integration.html">Using Impala with Kudu</a>
- </li>
- <li>
-
- <a href="administration.html">Administering Kudu</a>
- </li>
- <li>
-
- <a href="troubleshooting.html">Troubleshooting Kudu</a>
- </li>
- <li>
-
- <a href="developing.html">Developing Applications with Kudu</a>
- </li>
- <li>
-
- <a href="schema_design.html">Kudu Schema Design</a>
- </li>
- <li>
-
- <a href="security.html">Kudu Security</a>
- </li>
- <li>
-
- <a href="transaction_semantics.html">Kudu Transaction Semantics</a>
- </li>
- <li>
-<span class="active-toc">Background Maintenance Tasks</span>
- <ul class="sectlevel1">
-<li><a href="#_maintenance_manager">Maintenance manager</a></li>
-<li><a href="#_flushing_data_to_disk">Flushing data to disk</a></li>
-<li><a href="#_compacting_on_disk_data">Compacting on-disk data</a></li>
-<li><a href="#_write_ahead_log_gc">Write-ahead log GC</a></li>
-<li><a href="#_tablet_history_gc_and_the_ancient_history_mark">Tablet history GC and the ancient history mark</a></li>
-</ul>
- </li>
- <li>
-
- <a href="configuration_reference.html">Kudu Configuration Reference</a>
- </li>
- <li>
-
- <a href="command_line_tools_reference.html">Kudu Command Line Tools Reference</a>
- </li>
- <li>
-
- <a href="known_issues.html">Known Issues and Limitations</a>
- </li>
- <li>
-
- <a href="contributing.html">Contributing to Kudu</a>
- </li>
- <li>
-
- <a href="export_control.html">Export Control Notice</a>
- </li>
- </ul>
- </div>
- </div>
- </div>
-</div>
\ No newline at end of file
diff --git a/docs/command_line_tools.html b/docs/command_line_tools.html
deleted file mode 100644
index b3df48f..0000000
--- a/docs/command_line_tools.html
+++ /dev/null
@@ -1,3023 +0,0 @@
----
-title: Command Hierarchy
-layout: default
-active_nav: docs
-last_updated: 'Last updated 2018-06-18 07:37:43 PDT'
----
-<!--
-
-Licensed under the Apache License, Version 2.0 (the "License");
-you may not use this file except in compliance with the License.
-You may obtain a copy of the License at
-
- http://www.apache.org/licenses/LICENSE-2.0
-
-Unless required by applicable law or agreed to in writing, software
-distributed under the License is distributed on an "AS IS" BASIS,
-WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-See the License for the specific language governing permissions and
-limitations under the License.
--->
-
-
-<div class="container">
- <div class="row">
- <div class="col-md-9">
-
-<h1>Command Hierarchy</h1>
- <div id="preamble">
-<div class="sectionbody">
-<div class="ulist">
-<ul>
-<li>
-<p><a href="#fs">fs</a></p>
-<div class="ulist">
-<ul>
-<li>
-<p><a href="#fs-check">check</a></p>
-</li>
-<li>
-<p><a href="#fs-format">format</a></p>
-</li>
-<li>
-<p><a href="#fs-list">list</a></p>
-</li>
-<li>
-<p><a href="#fs-update_dirs">update_dirs</a></p>
-</li>
-<li>
-<p><a href="#fs-dump">dump</a></p>
-<div class="ulist">
-<ul>
-<li>
-<p><a href="#dump-block">block</a></p>
-</li>
-<li>
-<p><a href="#dump-cfile">cfile</a></p>
-</li>
-<li>
-<p><a href="#dump-tree">tree</a></p>
-</li>
-<li>
-<p><a href="#dump-uuid">uuid</a></p>
-</li>
-</ul>
-</div>
-</li>
-</ul>
-</div>
-</li>
-<li>
-<p><a href="#local_replica">local_replica</a></p>
-<div class="ulist">
-<ul>
-<li>
-<p><a href="#local_replica-copy_from_remote">copy_from_remote</a></p>
-</li>
-<li>
-<p><a href="#local_replica-data_size">data_size</a></p>
-</li>
-<li>
-<p><a href="#local_replica-delete">delete</a></p>
-</li>
-<li>
-<p><a href="#local_replica-list">list</a></p>
-</li>
-<li>
-<p><a href="#local_replica-cmeta">cmeta</a></p>
-<div class="ulist">
-<ul>
-<li>
-<p><a href="#cmeta-print_replica_uuids">print_replica_uuids</a></p>
-</li>
-<li>
-<p><a href="#cmeta-rewrite_raft_config">rewrite_raft_config</a></p>
-</li>
-<li>
-<p><a href="#cmeta-set_term">set_term</a></p>
-</li>
-</ul>
-</div>
-</li>
-<li>
-<p><a href="#local_replica-dump">dump</a></p>
-<div class="ulist">
-<ul>
-<li>
-<p><a href="#dump-block_ids">block_ids</a></p>
-</li>
-<li>
-<p><a href="#dump-meta">meta</a></p>
-</li>
-<li>
-<p><a href="#dump-rowset">rowset</a></p>
-</li>
-<li>
-<p><a href="#dump-wals">wals</a></p>
-</li>
-</ul>
-</div>
-</li>
-</ul>
-</div>
-</li>
-<li>
-<p><a href="#master">master</a></p>
-<div class="ulist">
-<ul>
-<li>
-<p><a href="#master-set_flag">set_flag</a></p>
-</li>
-<li>
-<p><a href="#master-status">status</a></p>
-</li>
-<li>
-<p><a href="#master-timestamp">timestamp</a></p>
-</li>
-<li>
-<p><a href="#master-list">list</a></p>
-</li>
-</ul>
-</div>
-</li>
-<li>
-<p><a href="#pbc">pbc</a></p>
-<div class="ulist">
-<ul>
-<li>
-<p><a href="#pbc-dump">dump</a></p>
-</li>
-<li>
-<p><a href="#pbc-edit">edit</a></p>
-</li>
-</ul>
-</div>
-</li>
-<li>
-<p><a href="#perf">perf</a></p>
-<div class="ulist">
-<ul>
-<li>
-<p><a href="#perf-loadgen">loadgen</a></p>
-</li>
-</ul>
-</div>
-</li>
-<li>
-<p><a href="#remote_replica">remote_replica</a></p>
-<div class="ulist">
-<ul>
-<li>
-<p><a href="#remote_replica-check">check</a></p>
-</li>
-<li>
-<p><a href="#remote_replica-copy">copy</a></p>
-</li>
-<li>
-<p><a href="#remote_replica-delete">delete</a></p>
-</li>
-<li>
-<p><a href="#remote_replica-dump">dump</a></p>
-</li>
-<li>
-<p><a href="#remote_replica-list">list</a></p>
-</li>
-<li>
-<p><a href="#remote_replica-unsafe_change_config">unsafe_change_config</a></p>
-</li>
-</ul>
-</div>
-</li>
-<li>
-<p><a href="#table">table</a></p>
-<div class="ulist">
-<ul>
-<li>
-<p><a href="#table-delete">delete</a></p>
-</li>
-<li>
-<p><a href="#table-list">list</a></p>
-</li>
-</ul>
-</div>
-</li>
-<li>
-<p><a href="#tablet">tablet</a></p>
-<div class="ulist">
-<ul>
-<li>
-<p><a href="#tablet-leader_step_down">leader_step_down</a></p>
-</li>
-<li>
-<p><a href="#tablet-change_config">change_config</a></p>
-<div class="ulist">
-<ul>
-<li>
-<p><a href="#change_config-add_replica">add_replica</a></p>
-</li>
-<li>
-<p><a href="#change_config-change_replica_type">change_replica_type</a></p>
-</li>
-<li>
-<p><a href="#change_config-move_replica">move_replica</a></p>
-</li>
-<li>
-<p><a href="#change_config-remove_replica">remove_replica</a></p>
-</li>
-</ul>
-</div>
-</li>
-</ul>
-</div>
-</li>
-<li>
-<p><a href="#test">test</a></p>
-<div class="ulist">
-<ul>
-<li>
-<p><a href="#test-mini_cluster">mini_cluster</a></p>
-</li>
-</ul>
-</div>
-</li>
-<li>
-<p><a href="#tserver">tserver</a></p>
-<div class="ulist">
-<ul>
-<li>
-<p><a href="#tserver-set_flag">set_flag</a></p>
-</li>
-<li>
-<p><a href="#tserver-status">status</a></p>
-</li>
-<li>
-<p><a href="#tserver-timestamp">timestamp</a></p>
-</li>
-<li>
-<p><a href="#tserver-list">list</a></p>
-</li>
-</ul>
-</div>
-</li>
-<li>
-<p><a href="#wal">wal</a></p>
-<div class="ulist">
-<ul>
-<li>
-<p><a href="#wal-dump">dump</a></p>
-</li>
-</ul>
-</div>
-</li>
-</ul>
-</div>
-</div>
-</div>
-<h1 id="_command_details" class="sect0"><a class="link" href="#_command_details">Command Details</a></h1>
-<div class="sect1">
-<h2 id="cluster"><a class="link" href="#cluster"><code>cluster</code>: Operate on a Kudu cluster</a></h2>
-<div class="sectionbody">
-<div class="paragraph">
-<p><br></p>
-</div>
-<div class="sect2">
-<h3 id="cluster-ksck"><a class="link" href="#cluster-ksck"><code>ksck</code>: Check the health of a Kudu cluster </a></h3>
-<div class="paragraph">
-<p>By default, ksck checks that master and tablet server processes are running, and that table metadata is consistent. Use the 'checksum' flag to check that tablet data is consistent (also see the 'tables' and 'tablets' flags). Use the 'checksum_snapshot' along with 'checksum' if the table or tablets are actively receiving inserts or updates. Use the 'verbose' flag to output detailed information on cluster status even if no inconsistency is found in metadata.<br>
-<strong>Usage:</strong><br>
-<code>kudu cluster ksck <master_addresses> [-checksum_cache_blocks] [-checksum_scan] [-checksum_scan_concurrency=<concurrency>] [-nochecksum_snapshot] [-checksum_timeout_sec=<sec>] [-color=<color>] [-noconsensus] [-tables=<tables>] [-tablets=<tablets>] [-verbose]</code>
-<br>
-<strong>Arguments:</strong></p>
-</div>
-<table class="tableblock frame-topbot grid-all spread">
-<colgroup>
-<col style="width: 25%;">
-<col style="width: 25%;">
-<col style="width: 25%;">
-<col style="width: 25%;">
-</colgroup>
-<thead>
-<tr>
-<th class="tableblock halign-left valign-top">Name</th>
-<th class="tableblock halign-left valign-top">Description</th>
-<th class="tableblock halign-left valign-top">Type</th>
-<th class="tableblock halign-left valign-top">Default</th>
-</tr>
-</thead>
-<tbody>
-<tr>
-<td class="tableblock halign-left valign-top"><p class="tableblock">master_addresses</p></td>
-<td class="tableblock halign-left valign-top"><p class="tableblock">Comma-separated list of Kudu Master addresses where each address is of form 'hostname:port'</p></td>
-<td class="tableblock halign-left valign-top"><p class="tableblock">string</p></td>
-<td class="tableblock halign-left valign-top"><p class="tableblock">none</p></td>
-</tr>
-<tr>
-<td class="tableblock halign-left valign-top"><p class="tableblock">checksum_cache_blocks (optional)</p></td>
-<td class="tableblock halign-left valign-top"><p class="tableblock">Should the checksum scanners cache the read blocks</p></td>
-<td class="tableblock halign-left valign-top"><p class="tableblock">bool</p></td>
-<td class="tableblock halign-left valign-top"><p class="tableblock"><code>false</code></p></td>
-</tr>
-<tr>
-<td class="tableblock halign-left valign-top"><p class="tableblock">checksum_scan (optional)</p></td>
-<td class="tableblock halign-left valign-top"><p class="tableblock">Perform a checksum scan on data in the cluster.</p></td>
-<td class="tableblock halign-left valign-top"><p class="tableblock">bool</p></td>
-<td class="tableblock halign-left valign-top"><p class="tableblock"><code>false</code></p></td>
-</tr>
-<tr>
-<td class="tableblock halign-left valign-top"><p class="tableblock">checksum_scan_concurrency (optional)</p></td>
-<td class="tableblock halign-left valign-top"><p class="tableblock">Number of concurrent checksum scans to execute per tablet server.</p></td>
-<td class="tableblock halign-left valign-top"><p class="tableblock">int32</p></td>
-<td class="tableblock halign-left valign-top"><p class="tableblock"><code>4</code></p></td>
-</tr>
-<tr>
-<td class="tableblock halign-left valign-top"><p class="tableblock">checksum_snapshot (optional)</p></td>
-<td class="tableblock halign-left valign-top"><p class="tableblock">Should the checksum scanner use a snapshot scan</p></td>
-<td class="tableblock halign-left valign-top"><p class="tableblock">bool</p></td>
-<td class="tableblock halign-left valign-top"><p class="tableblock"><code>true</code></p></td>
-</tr>
-<tr>
-<td class="tableblock halign-left valign-top"><p class="tableblock">checksum_timeout_sec (optional)</p></td>
-<td class="tableblock halign-left valign-top"><p class="tableblock">Maximum total seconds to wait for a checksum scan to complete before timing out.</p></td>
-<td class="tableblock halign-left valign-top"><p class="tableblock">int32</p></td>
-<td class="tableblock halign-left valign-top"><p class="tableblock"><code>3600</code></p></td>
-</tr>
-<tr>
-<td class="tableblock halign-left valign-top"><p class="tableblock">color (optional)</p></td>
-<td class="tableblock halign-left valign-top"><p class="tableblock">Specifies whether output should be colorized. The default value 'auto' colorizes output if the output is a terminal. The other valid values are 'always' or 'never'.</p></td>
-<td class="tableblock halign-left valign-top"><p class="tableblock">string</p></td>
-<td class="tableblock halign-left valign-top"><p class="tableblock"><code>auto</code></p></td>
-</tr>
-<tr>
-<td class="tableblock halign-left valign-top"><p class="tableblock">consensus (optional)</p></td>
-<td class="tableblock halign-left valign-top"><p class="tableblock">Whether to check the consensus state from each tablet against the master.</p></td>
-<td class="tableblock halign-left valign-top"><p class="tableblock">bool</p></td>
-<td class="tableblock halign-left valign-top"><p class="tableblock"><code>true</code></p></td>
-</tr>
-<tr>
-<td class="tableblock halign-left valign-top"><p class="tableblock">tables (optional)</p></td>
-<td class="tableblock halign-left valign-top"><p class="tableblock">Tables to check (comma-separated list of names). If not specified, checks all tables.</p></td>
-<td class="tableblock halign-left valign-top"><p class="tableblock">string</p></td>
-<td class="tableblock halign-left valign-top"><p class="tableblock">none</p></td>
-</tr>
-<tr>
-<td class="tableblock halign-left valign-top"><p class="tableblock">tablets (optional)</p></td>
-<td class="tableblock halign-left valign-top"><p class="tableblock">Tablets to check (comma-separated list of IDs) If not specified, checks all tablets.</p></td>
-<td class="tableblock halign-left valign-top"><p class="tableblock">string</p></td>
-<td class="tableblock halign-left valign-top"><p class="tableblock">none</p></td>
-</tr>
-<tr>
-<td class="tableblock halign-left valign-top"><p class="tableblock">verbose (optional)</p></td>
-<td class="tableblock halign-left valign-top"><p class="tableblock">Output detailed information even if no inconsistency is found.</p></td>
-<td class="tableblock halign-left valign-top"><p class="tableblock">bool</p></td>
-<td class="tableblock halign-left valign-top"><p class="tableblock"><code>false</code></p></td>
-</tr>
-</tbody>
-</table>
-<div class="paragraph">
-<p><br></p>
-</div>
-</div>
-</div>
-</div>
-<div class="sect1">
-<h2 id="fs"><a class="link" href="#fs"><code>fs</code>: Operate on a local Kudu filesystem</a></h2>
-<div class="sectionbody">
-<div class="paragraph">
-<p><br></p>
-</div>
-<div class="sect2">
-<h3 id="fs-check"><a class="link" href="#fs-check"><code>check</code>: Check a Kudu filesystem for inconsistencies </a></h3>
-<div class="paragraph">
-<p><strong>Usage:</strong><br>
-<code>kudu fs check [-fs_data_dirs=<dirs>] [-fs_metadata_dir=<dir>] [-fs_wal_dir=<dir>] [-repair]</code>
-<br>
-<strong>Arguments:</strong></p>
-</div>
-<table class="tableblock frame-topbot grid-all spread">
-<colgroup>
-<col style="width: 25%;">
-<col style="width: 25%;">
-<col style="width: 25%;">
-<col style="width: 25%;">
-</colgroup>
-<thead>
-<tr>
-<th class="tableblock halign-left valign-top">Name</th>
-<th class="tableblock halign-left valign-top">Description</th>
-<th class="tableblock halign-left valign-top">Type</th>
-<th class="tableblock halign-left valign-top">Default</th>
-</tr>
-</thead>
-<tbody>
-<tr>
-<td class="tableblock halign-left valign-top"><p class="tableblock">fs_data_dirs (optional)</p></td>
-<td class="tableblock halign-left valign-top"><p class="tableblock">Comma-separated list of directories with data blocks. If this is not specified, fs_wal_dir will be used as the sole data block directory.</p></td>
-<td class="tableblock halign-left valign-top"><p class="tableblock">string</p></td>
-<td class="tableblock halign-left valign-top"><p class="tableblock">none</p></td>
-</tr>
-<tr>
-<td class="tableblock halign-left valign-top"><p class="tableblock">fs_metadata_dir (optional)</p></td>
-<td class="tableblock halign-left valign-top"><p class="tableblock">Directory with metadata. If this is not specified, for compatibility with Kudu 1.6 and below, Kudu will check the first entry of fs_data_dirs for metadata and use it as the metadata directory if any exists. If none exists, fs_wal_dir will be used as the metadata directory.</p></td>
-<td class="tableblock halign-left valign-top"><p class="tableblock">string</p></td>
-<td class="tableblock halign-left valign-top"><p class="tableblock">none</p></td>
-</tr>
-<tr>
-<td class="tableblock halign-left valign-top"><p class="tableblock">fs_wal_dir (optional)</p></td>
-<td class="tableblock halign-left valign-top"><p class="tableblock">Directory with write-ahead logs. If this is not specified, the program will not start. Ma
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