Such timeout can occur when Solr is not able to obtain cluster state. If following call is results in timeout, then this is the case
http://solr-hostname:8983/solr/admin/collections?action=CLUSTERSTATUS&wt=json
This may be caused by incorrect entries present in /clusterstate.json
To fix this:
-
get clusterstate from ZooKeeper by calling
zkcli.sh -zkhost localhost:2181 -cmd get /clusterstate.json > clusterstate.json
- edit extracted
clusterstate.json
file and remove sections with wrong IPs or not existing hosts -
clear the clusterstate in ZooKeeper by calling
zkcli.sh -zkhost localhost:2181 -cmd clear /clusterstate.json
-
save corrected state in ZooKeeper by sending updated JSON file
zkcli.sh -zkhost localhost:2181 -cmd putfile /clusterstate.json ./clusterstate.json`
- restart Solr instances
After that, if your clusterstate shows correct info, you should no longer have timeouts when accessing Collections API.
Note
Be careful when editing clusterstate JSON, limit your changes only to removing not existing hosts/replicas/shards.