Collection timeout error

[Manohar Sripada <ma...@gmail.com>]

I am getting collection timeout error while creating collection on Solr
Cloud. Below is the error.

> org.apache.solr.common.SolrException: createcollection the collection
time out:180s
 at
org.apache.solr.handler.admin.CollectionsHandler.handleResponse(CollectionsHandler.java:252)
 at
org.apache.solr.handler.admin.CollectionsHandler.handleResponse(CollectionsHandler.java:233)


This SolrCloud was up and running from 2 weeks. Prior to this, I have
created/deleted/reloaded collections on this SolrCloud. Suddenly, I started
getting this error while trying to create a collection. I am using external
Zookeeper ensemble.

When I tried to connect to Zookeeper ensemble through command line. Below
is something I found out.

> ls /overseer/collection-queue-work

[qn-0000000030, qn-0000000020, qn-0000000026, qn-0000000018, qn-0000000028,
qn-0000000016, qn-0000000022, qn-0000000014, qn-0000000024, qn-0000000012]

> get /overseer/collection-queue-work/qn-0000000012

{

  "operation":"createcollection",

  "fromApi":"true",

  "name":"coll_4",

  "replicationFactor":"2",

  "collection.configName":"collConfig",

  "numShards":"16",

  "maxShardsPerNode":"4"}


There are many such requests which were in queue. All are related to
Collection API requests (eg: CREATE, DELETE, RELOAD etc). Can anyone please
tell me why Solr/ZK went into this state only for collection related APIs?
Although restart of Solr and Zookeeper worked, but, I can't ask for a
restart in production whenever this occurs. So, wanted to find the root
cause.



Thanks