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Posted to issues@ratis.apache.org by "Tsz Wo Nicholas Sze (JIRA)" <ji...@apache.org> on 2019/03/11 23:53:00 UTC

[jira] [Updated] (RATIS-495) Leader Election thread might crash if two servers having the same id

     [ https://issues.apache.org/jira/browse/RATIS-495?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Tsz Wo Nicholas Sze updated RATIS-495:
--------------------------------------
    Description: 
When two servers is (mis)configured with the same id, thread running LeaderElection#waitForResults might crash. 

{code:java}
try {
if (conf.hasMajority(votedPeers, server.getId())) {
}
} catch(ExecutionException e) {}
 
boolean hasMajority(Collection<RaftPeerId> others, RaftPeerId selfId) { 
Preconditions.assertTrue(!others.contains(selfId)); 
return conf.hasMajority(others, selfId) && (oldConf == null || oldConf.hasMajority(others, selfId));
}
{code}
Preconditions.assertTrue(!others.contains(selfId)); statement inside RaftConfiguration#hasMajority() might throw IllegalStateException. This RunTimeException will kill thread running LeaderElection#waitForResults code.

stacktrace:
{code:java}
Exception in thread "Thread-13" java.lang.IllegalStateException
 at org.apache.ratis.util.Preconditions.assertTrue(Preconditions.java:33)
 at org.apache.ratis.server.impl.RaftConfiguration.hasMajority(RaftConfiguration.java:211)
 at org.apache.ratis.server.impl.LeaderElection.waitForResults(LeaderElection.java:225)
 at org.apache.ratis.server.impl.LeaderElection.askForVotes(LeaderElection.java:146)
 at org.apache.ratis.server.impl.LeaderElection.run(LeaderElection.java:102){code}


  was:
In some scenario, thread running LeaderElection#waitForResults might crash. 

 
{code:java}
try {
if (conf.hasMajority(votedPeers, server.getId())) {
}
} catch(ExecutionException e) {}
 
boolean hasMajority(Collection<RaftPeerId> others, RaftPeerId selfId) { 
Preconditions.assertTrue(!others.contains(selfId)); 
return conf.hasMajority(others, selfId) && (oldConf == null || oldConf.hasMajority(others, selfId));
}
{code}
Preconditions.assertTrue(!others.contains(selfId)); statement inside RaftConfiguration#hasMajority() might throw IllegalStateException. This RunTimeException will kill thread running LeaderElection#waitForResults code.

stacktrace:
{code:java}
Exception in thread "Thread-13" java.lang.IllegalStateException
 at org.apache.ratis.util.Preconditions.assertTrue(Preconditions.java:33)
 at org.apache.ratis.server.impl.RaftConfiguration.hasMajority(RaftConfiguration.java:211)
 at org.apache.ratis.server.impl.LeaderElection.waitForResults(LeaderElection.java:225)
 at org.apache.ratis.server.impl.LeaderElection.askForVotes(LeaderElection.java:146)
 at org.apache.ratis.server.impl.LeaderElection.run(LeaderElection.java:102){code}
 

Fix: Change ExecutionException into Exception. Also I need to figure out what is causing this RunTimeException. 

        Summary: Leader Election thread might crash if two servers having the same id  (was: Leader Election thread might crash without coming back)

[~andywu], these are good suggestions.  Thanks.

Updated summary and description.

> Leader Election thread might crash if two servers having the same id
> --------------------------------------------------------------------
>
>                 Key: RATIS-495
>                 URL: https://issues.apache.org/jira/browse/RATIS-495
>             Project: Ratis
>          Issue Type: Bug
>    Affects Versions: 0.2.0
>            Reporter: Andy Wu
>            Priority: Major
>
> When two servers is (mis)configured with the same id, thread running LeaderElection#waitForResults might crash. 
> {code:java}
> try {
> if (conf.hasMajority(votedPeers, server.getId())) {
> }
> } catch(ExecutionException e) {}
>  
> boolean hasMajority(Collection<RaftPeerId> others, RaftPeerId selfId) { 
> Preconditions.assertTrue(!others.contains(selfId)); 
> return conf.hasMajority(others, selfId) && (oldConf == null || oldConf.hasMajority(others, selfId));
> }
> {code}
> Preconditions.assertTrue(!others.contains(selfId)); statement inside RaftConfiguration#hasMajority() might throw IllegalStateException. This RunTimeException will kill thread running LeaderElection#waitForResults code.
> stacktrace:
> {code:java}
> Exception in thread "Thread-13" java.lang.IllegalStateException
>  at org.apache.ratis.util.Preconditions.assertTrue(Preconditions.java:33)
>  at org.apache.ratis.server.impl.RaftConfiguration.hasMajority(RaftConfiguration.java:211)
>  at org.apache.ratis.server.impl.LeaderElection.waitForResults(LeaderElection.java:225)
>  at org.apache.ratis.server.impl.LeaderElection.askForVotes(LeaderElection.java:146)
>  at org.apache.ratis.server.impl.LeaderElection.run(LeaderElection.java:102){code}



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