Hey all, I wanted to get some feedback from you'all on a recent usecase I was
asked about. I suspect the answer will be "Use Solr Operator", but here goes!
I have an environment where I have 5 or so single shard collections. Much of
the time I run just a single node and each collection is a single shard with no
replicas. Sometimes, to support load, I'll add another node or two. Then
I'll add replicas so cover the new nodes, 1 per node. So with three nodes, I
have one leader and two replicas. Add two more nodes, move to one leader and
four replicas.
However, when I remove a node by shutting it down, then Zookeeper never get's
notified about this, and so the replica is listed as down, and the node is
listed as down in red in the UI. When it isn't really red, it's just we don't
need it for now, and it's not coming back.
I'd like to just declare "For this collection, I want one replica per node
based on however many nodes are current". I don't want to call the various
commands myself to add replicas and or remove then as nodes are added or
removed. And I don't want to call various apis or other complex things when I
add or remove a node, I just want bin/solr stop and bin/solr start to be run
;-).
I think this is what Replica Placement Plugins were for maybe? Could I have a
Replica Placement strategy that when ZK sees a new node added, then creates a
new replica on it, and vice versa, when a node goes away, it just removes that
replica instead of treating it as "down"?
Thoughts?
Eric
