On 2/18/2021 8:20 AM, DAVID MARTIN NIETO wrote:
We've a solr cluster with 4 solr servers and 5 zookeepers in HA mode.
We've tested about if our cluster can mantain the service with only the half of
the cluster, in case of disaster os similar, and we've a problem with the
zookepers config and its static configuration.
In the start script of the 4 solrs servers there are a list of 5 ip:port of the 5
zookeepers of the cluster, so when we "lost" the half of machines (we've 2 zoos
in one machine and 3 on another) in the worst case we lost 3 of these 5 zookeepers. We
can start a sixth zookeeper (to have 3 with the half of cluster stopped) but to add in
the solr server we need to stop and restart with a new list of ip:port adding it and
that's not an automatic or dynamic thing.
In order to have a highly available zookeeper, you must have at least
three separate physical servers for ZK. Running multiple zookeepers on
one physical machine gains you nothing ... because if the whole machine
fails, you lose all of those zookeepers. If you have three physical
servers, one can fail with no problems. If you have five separate
physical servers running ZK, then two of the machines can fail without
taking the cluster down.
¿Somebody knows another configuration or workaround to have a dynamic list of
zoos and start or stop some of thems without changes in the config and
start/stop the solr server?
The Zookeeper client was upgraded to 3.5 in Solr 8.2.0.
https://issues.apache.org/jira/browse/SOLR-8346
If you're running at least Solr 8.2.0, and your ZK servers are at least
version 3.5, then ZK should support dynamic cluster reconfiguration.
The ZK status page in the admin UI may have some problems after ZK
undergoes a dynamic reconfiguration, but SolrCloud's core functionality
should work fine.
Thanks,
Shawn
