[jira] [Commented] (CASSANDRA-7109) Create replace_address dtest

["Ryan McGuire (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/CASSANDRA-7109?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13984772#comment-13984772 ] 

Ryan McGuire commented on CASSANDRA-7109:
-----------------------------------------

Shawn,

The replace_address feature of cassandra is a JVM parameter telling a node that it is taking over for a node that is no longer a part of the cluster. 

Here's a quick set of tests I ran on the command line with ccm:

{code}
# Create a 3 node cluster:
ccm create -v git:cassandra-2.1 -n 3 -s test

# Create some data on it, with a replication factor of 3:
ccm node1 stress -- write n=10000 -schema replication\(factor=3\)

# Kill -9 node 3 
ccm node3 stop --not-gently

# Connect to node1 to test the data:
ccm node1 cqlsh -- --cqlversion=3.1.6 localhost 9042

cqlsh> CONSISTENCY one;
cqlsh> select * from "Keyspace1"."Standard1" LIMIT 1;
cqlsh> CONSISTENCY two;
cqlsh> select * from "Keyspace1"."Standard1" LIMIT 1;
cqlsh> CONSISTENCY all;
cqlsh> select * from "Keyspace1"."Standard1" LIMIT 1;

# The last query there fails because it cannot get all replicas.

# Add a new node to the cluster:
ccm add node4 -i 127.0.0.4 -j 7400 -b
# Tell it that it is replacing node3:
ccm node4 start --replace-address=127.0.0.3

ccm node1 cqlsh -- --cqlversion=3.1.6 localhost 9042
cqlsh> CONSISTENCY all;
cqlsh> select * from "Keyspace1"."Standard1" LIMIT 1;

# Query works again.
{code}

Like Tyler Hobbs mentioned in this chat snippet, we need to test replacing an node that's down, replacing a node that is still active (shouldn't work hopefully.) and replacing a node that doesn't exist. 

> Create replace_address dtest
> ----------------------------
>
>                 Key: CASSANDRA-7109
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-7109
>             Project: Cassandra
>          Issue Type: Test
>            Reporter: Ryan McGuire
>            Assignee: Shawn Kumar
>
> {noformat}
> 16:03 < driftx> well, this just bothers me because either it's been broken for almost ever, or something 
>                 broke in cassandra.
> 16:43 < thobbs> driftx: I'm testing your patch on #6622, but I'm seeing a bit of a weird error:
> 16:43 < CassBotJr> https://issues.apache.org/jira/browse/CASSANDRA-6622 (Unresolved; 1.2.16, 2.0.6): 
>                    "Streaming session failures during node replace of same address"
> 16:43 < thobbs> java.lang.UnsupportedOperationException: Cannot replace token -1017822742317066613 which does 
>                 not exist!
> 16:44 < thobbs> this is on 2.0 with the patch applied
> 16:44 < driftx> O_o
> 16:44 < thobbs> I'm just stopping a ccm node, clearing it, then starting with replace_address (auto_bootstrap 
>                 = true, not a seed, initial_tokens is null)
> 16:45 < driftx> oh, I'm stupid, hang on
> 16:47 < rcoli> is the sum of that that replace_* is still broken in 2.0 ?
> 16:47 < rcoli> err, 1.2?
> 16:48 < driftx> thobbs: updated the patch
> 16:48 < thobbs> rcoli: only for replacing the same address
> 16:48 < rcoli> is there another case?
> 16:49 < driftx> replacing with a different address.
> 16:49 < rcoli> oh, right, _address_
> 16:49 < rcoli> I'm still modeling this as replace _token_
> 16:49 < rcoli> in my brain
> 16:49 < driftx> same address never broke for me though, so you can probably just retry
> 16:55 < thobbs> can we add a dtest for replace_address coverage?  It's kind of annoying to test manually and 
>                 we've managed to break it a few times
> 16:56 < thobbs> I have a PR against ccm open to add replace_address support: 
>                 https://github.com/pcmanus/ccm/pull/85
> 16:57 < driftx> I could have sworn we had one
> 16:58 < driftx> we do but it's using replace_token so probably not even running now
> 16:58 < thobbs> yeah
> 16:58 < thobbs> it would be nice to cover replacing the same address, another address, and expected failures 
>                 like replacing a still-live node
> 16:59 < driftx> +1
> {noformat}



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