[
https://issues.apache.org/jira/browse/SOLR-17519?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17914583#comment-17914583
]
Andrzej Bialecki commented on SOLR-17519:
-----------------------------------------
The original use case for HttpClusterStateProvider was to be able to use
CloudSolrClient and its load-balancing and routing logic in a situation when
Solr's ZK is locked down, i.e. when only Solr nodes are exposed for
indexing/search but the client has no access to the cluster's ZK.
In such situations it would make sense to keep the "bootstrap" Solr URLs
around, even if they are not live at the moment, to be able to again bootstrap
the current list of live nodes - because the client doesn't have access to any
other method for discovering the current live nodes.
> CloudSolrClient with HTTP ClusterState can forget live nodes and then fail
> --------------------------------------------------------------------------
>
> Key: SOLR-17519
> URL: https://issues.apache.org/jira/browse/SOLR-17519
> Project: Solr
> Issue Type: Bug
> Security Level: Public(Default Security Level. Issues are Public)
> Components: SolrCloud, SolrJ
> Reporter: David Smiley
> Priority: Major
> Labels: newdev, pull-request-available
> Time Spent: 2.5h
> Remaining Estimate: 0h
>
> When using CloudSolrClient with HTTP URLs to Solr for the cluster state:
> If all live nodes disappear temporarily (hard cluster restart?), the client
> can permanently fail to talk to the cluster, and thus would need to be
> restarted to recover.
> Credit [~ilan] on the dev list:
> {quote}The current implementation removes non live nodes from the set of
> nodes to connect to. Getting the live nodes requires connecting to a specific
> node in the cluster that is therefore live when that happens. Worst case, if
> there is a single node up in the cluster, the client ends with a single node
> in its connection candidates list. For the issue to manifest, that Solr node
> then has to go down. Subsequently, even if other nodes are up, the client
> only has the address of a down node and can't connect.
> The fix is not a big deal. Nodes initially passed as configuration to the
> client should never be removed from the set of candidate nodes to connect to,
> even if they are not live. Other live nodes could be added to that set (and
> removed from it if we so desire when they are no longer live) to increase
> resiliency in case the cluster does have live nodes but all initially
> configured nodes are not live. The design issue is treating the configured
> set of nodes to connect to and the set of live nodes as one thing.
> {quote}
> See org.apache.solr.client.solrj.impl.BaseHttpClusterStateProvider
--
This message was sent by Atlassian Jira
(v8.20.10#820010)
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
