[SOLR-8862] /live_nodes is populated too early to be very useful for clients -- CloudSolrClient (and MiniSolrCloudCluster.createCollection) need some other ephemeral zk node to knowwhich servers are "ready"

• Type: Bug
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Assignee: Unassigned
• Reporter: Chris M. Hostetter
• Created: 16/Mar/16 23:19
• Updated: 22/Mar/16 16:40

Description

/live_nodes is populated surprisingly early (and multiple times) in the life cycle of a sole node startup, and as a result probably shouldn't be used by CloudSolrClient (or other "smart" clients) for deciding what servers are fair game for requests.

we should either fix /live_nodes to be created later in the lifecycle, or add some new ZK node for this purpose.

original bug report

I haven't been able to make sense of this yet, but what i'm seeing in a new SolrCloudTestCase subclass i'm writing is that the code below, which (reasonably) attempts to create a collection immediately after configuring the MiniSolrCloudCluster gets a "SolrServerException: No live SolrServers available to handle this request" – in spite of the fact, that (as far as i can tell at first glance) MiniSolrCloudCluster's constructor is suppose to block until all the servers are live..

    configureCluster(numServers)
      .addConfig(configName, configDir.toPath())
      .configure();
    Map<String, String> collectionProperties = ...;
    assertNotNull(cluster.createCollection(COLLECTION_NAME, numShards, repFactor,
                                           configName, null, null, collectionProperties));