On 2/27/2018 1:36 AM, zahra121 wrote:
Suppose I have a node which is a leader in SolrCloud.
When I block this leader's SolrCloud and Zookeeper ports by the command
"firewall-cmd --remove-port=<SolrPort>/tcp --permanent", the leader does not
change automatically and this leader status remains active in solr admin UI.
Thus, I decided to change the leader manually. I tried REBALANCELEADERS and
ADDROLE commands in solrCloud, however the leader did not change!
I am not completely familiar with how SolrCloud handles down servers,
but I don't think it proactively does any kind of "ping" to make sure
they're still up. Probably you would need to send a request that
SolrCloud tries to send to the down server, so that the cluster can
notice that Solr is down and change the clusterstate.
ZK should be a lot more responsive to changes like that, because it DOES
use a ping-like mechanism to see if servers are up. Solr's admin UI
does not have any visibility into which ZK server is the leader, though
-- so you can't see the results of blocking a ZK server unless you look
at the ZK log.
Thanks,
Shawn
