Hi. Use Solr Operator :-)
Yea, I think you could write a placement plugin to act on node up/down events as you say. Perhaps with a delay of 10 minutes after a node goes away to call the DELETEREPLICA API, since you have to allow for normal node bounces. You could also write an external watchdog that monitors live_nodes and state.json in order to do the same. Personally, I go to Admin UI -> Collections -> myCollection -> shard1 -> replicaN -> Delete button before shutting down a node. As you may know, the Operator has a "drain pod" kind of hook designed to move replicas off of a POD that is being targeted for scaling down, and I think it calls some rebalance logic? Jan > 11. mars 2026 kl. 22:38 skrev David Eric Pugh via dev <[email protected]>: > > 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 --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
