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Posted to issues@hbase.apache.org by "Andrew Purtell (JIRA)" <ji...@apache.org> on 2011/04/12 23:46:05 UTC
[jira] [Created] (HBASE-3775) Unique transient names for processes
Unique transient names for processes
------------------------------------
Key: HBASE-3775
URL: https://issues.apache.org/jira/browse/HBASE-3775
Project: HBase
Issue Type: Brainstorming
Reporter: Andrew Purtell
HBASE-3772 is the latest of several incidents where regionservers and master map their identities to hostnames yet hostname resolution is inconsistent cluster wide. With HBase 0.20 we have seen this lead conditions like META being hosted on 11 servers at once. The situation with HBase 0.90 is better but it concerns me a lot. Confusion about identity cannot be anything but bad.
Why don't we have the processes generate for themselves a random UUID upon startup, or similar, and have all processes on the cluster map these UUIDs to identities? Critically, region assignment state should hold the UUID of the current assignee. This would not remove the need to resolve region locations to network addresses, nor determine liveness of assignments, but will prevent the specific double assignment scenarios we have seen if hostname resolution is flaky.
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[jira] [Commented] (HBASE-3775) Unique transient names for
processes
Posted by "stack (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/HBASE-3775?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13019187#comment-13019187 ]
stack commented on HBASE-3775:
------------------------------
1502 marks HServerAddress as deprecated and replaces most instances, all but those that bubble up to the API with a ServerName class. ServerName is just a host for a String formatted as <HOSTNAME> ',' <PORT> ',' <STARTCODE>. 1502 removes heartbeats. RS volunteers port and startcode. Master tells it what its hostname is. Thereafter, RS uses the 'String' the Master gave it for registering itself in ZK and for passing the master its load ever-after.
This was how 0.90.x was supposed to work but it the above protocol used HServerAddress which does a lookup on each deserialization. Now we just uses Strings to identify with startcode serving as a sort-of UUID but with the the ServerName human-readable rather than UUID opaque.
If you are game, lets try 1502 before we resort to UUIDs? Agree though that identity loss, theft, and change has made for way too much grief over the life of hbase.
> Unique transient names for processes
> ------------------------------------
>
> Key: HBASE-3775
> URL: https://issues.apache.org/jira/browse/HBASE-3775
> Project: HBase
> Issue Type: Brainstorming
> Reporter: Andrew Purtell
>
> HBASE-3772 is the latest of several incidents where regionservers and master map their identities to hostnames yet hostname resolution is inconsistent cluster wide. With HBase 0.20 we have seen this lead conditions like META being hosted on 11 servers at once. The situation with HBase 0.90 is better but it concerns me a lot. Confusion about identity cannot be anything but bad.
> Why don't we have the processes generate for themselves a random UUID upon startup, or similar, and have all processes on the cluster map these UUIDs to identities? Critically, region assignment state should hold the UUID of the current assignee. This would not remove the need to resolve region locations to network addresses, nor determine liveness of assignments, but will prevent the specific double assignment scenarios we have seen if hostname resolution is flaky.
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[jira] [Commented] (HBASE-3775) Unique transient names for
processes
Posted by "Lars Hofhansl (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/HBASE-3775?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13455474#comment-13455474 ]
Lars Hofhansl commented on HBASE-3775:
--------------------------------------
It seems this is no longer an issue. Agreed?
> Unique transient names for processes
> ------------------------------------
>
> Key: HBASE-3775
> URL: https://issues.apache.org/jira/browse/HBASE-3775
> Project: HBase
> Issue Type: Brainstorming
> Reporter: Andrew Purtell
>
> HBASE-3772 is the latest of several incidents where regionservers and master map their identities to hostnames yet hostname resolution is inconsistent cluster wide. With HBase 0.20 we have seen this lead conditions like META being hosted on 11 servers at once. The situation with HBase 0.90 is better but it concerns me a lot. Confusion about identity cannot be anything but bad.
> Why don't we have the processes generate for themselves a random UUID upon startup, or similar, and have all processes on the cluster map these UUIDs to identities? Critically, region assignment state should hold the UUID of the current assignee. This would not remove the need to resolve region locations to network addresses, nor determine liveness of assignments, but will prevent the specific double assignment scenarios we have seen if hostname resolution is flaky.
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[jira] [Resolved] (HBASE-3775) Unique transient names for processes
Posted by "stack (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/HBASE-3775?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
stack resolved HBASE-3775.
--------------------------
Resolution: Won't Fix
Marking as 'Wont Fix' with UUIDs. I think hbase-1502 ServerName addresses Andrew's concern. Reopen Andrew if you see hole in my reasoning.
> Unique transient names for processes
> ------------------------------------
>
> Key: HBASE-3775
> URL: https://issues.apache.org/jira/browse/HBASE-3775
> Project: HBase
> Issue Type: Brainstorming
> Reporter: Andrew Purtell
>
> HBASE-3772 is the latest of several incidents where regionservers and master map their identities to hostnames yet hostname resolution is inconsistent cluster wide. With HBase 0.20 we have seen this lead conditions like META being hosted on 11 servers at once. The situation with HBase 0.90 is better but it concerns me a lot. Confusion about identity cannot be anything but bad.
> Why don't we have the processes generate for themselves a random UUID upon startup, or similar, and have all processes on the cluster map these UUIDs to identities? Critically, region assignment state should hold the UUID of the current assignee. This would not remove the need to resolve region locations to network addresses, nor determine liveness of assignments, but will prevent the specific double assignment scenarios we have seen if hostname resolution is flaky.
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