lucene-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Jeff Wartes (JIRA)" <>
Subject [jira] [Commented] (SOLR-8531) ZK leader path changed in 5.4
Date Mon, 11 Jan 2016 04:46:39 GMT


Jeff Wartes commented on SOLR-8531:

I just looked again, and 5.4 is indeed writing the leader data to both places. Perhaps 5.4
is only looking in the new place?
This is speculation, but if so, a possible upgrade path might have been to try to get the
first 5.4 node for each shard to be the leader, (preferredLeader property?) and then the rest
of the rollout would work.  
As I mentioned, I didn't check what happened when I restarted a 5.3 node while 5.4 was leader

> ZK leader path changed in 5.4
> -----------------------------
>                 Key: SOLR-8531
>                 URL:
>             Project: Solr
>          Issue Type: Bug
>          Components: SolrCloud
>    Affects Versions: 5.4
>            Reporter: Jeff Wartes
> While doing a rolling upgrade from 5.3 to 5.4 of a solrcloud cluster, I observed that
upgraded nodes would not register their shards as active unless they were elected the leader
for the shard.
> There were no errors, the shards were fully up and responsive, but would not  publish
any change from the "down" state.
> This appears to be because the recovery process never happens, because the ZK node containing
the current leader can't be found, because the ZK path has changed.
> Specifically, the leader data node changed from:
> <collection>/leaders/<shard>
> to
> <collection>/leaders/<shard>/leader
> It looks to me like this happened during SOLR-7844, perhaps accidentally. 
> At the least, the "Migrating to Solr 5.4" section of the README should get updated with
this info, since it means a rolling upgrade of a collection with multiple replicas will suffer
serious degradation in the number of active replicas as nodes are upgraded. It's entirely
possible this will reduce some shards to a single active replica.

This message was sent by Atlassian JIRA

To unsubscribe, e-mail:
For additional commands, e-mail:

View raw message