I’ve been messing around with the Solr 7.2 autoscaling framework this week.
Some things seem trivial, but I’m also running into questions and issues. If
anyone else has experience with this stuff, I’d be glad to hear it.
Specifically:
Context:
-One collection, consisting of 42 shards, where up to 6 shards can fit on a
single node. (which means 7 nodes per Replication Factor)
-Three AZs, each with its own ip_2 value.
Goals:
Goal: Fully utilize available nodes.
Cluster Preference: {“maximize”: "cores”}
Goal: No node should have more than one replica of a given shard
Rule: {"replica": "<2", "shard": "#EACH", "node": "#ANY"}
Goal: No node should have more than 6 shards
Rule: {"replica": "<7", "node":"#ANY"}
Goal: Where possible, distinct RFs should each exist in an AZ.
(Example1: I’d like 7 nodes with a complete RF in AZ 1 and 7 nodes with a
complete RF in AZ 2, and not end up with, say, both shard2 replicas in AZ 1)
(Example2: If I have 14 nodes in AZ 1 and 7 in AZ 2, I should have two full RFs
in AZ 1 and one in AZ 2)
Rule: ???
I could have multiple non-strict rules perhaps? Like:
{"replica": "<2", "shard": "#EACH", "ip_2": "1", "strict":false}
{"replica": "<3", "shard": "#EACH", "ip_2": "1", "strict":false}
{"replica": "<4", "shard": "#EACH", "ip_2": "1", "strict":false}
{"replica": "<2", "shard": "#EACH", "ip_2": "2", "strict":false}
{"replica": "<3", "shard": "#EACH", "ip_2": "2", "strict":false}
{"replica": "<4", "shard": "#EACH", "ip_2": "2", "strict":false}
etc
So having more than one RF in an AZ is a technical “violation”, but if
placement minimizes non-strict violations, replicas would tend to get placed
correctly.
Given a working set of rules, I’m still having trouble with two things:
1. I’ve manually created the “.system” collection, as it didn’t seem to get
created automatically. However, autoscaling activity is not getting logged to
it.
2. I can’t seem to figure out how to scale up.
* I’d presumed editing the collection’s “replicationFactor” would do the
trick, but it does not.
* The “node-up” trigger will serve to replace lost replicas, but won’t
otherwise take advantage of additional capacity.
i. There’s
a UTILIZENODE command in 7.2, but it appears that’s still something you need to
trigger manually.
Anyone played with this stuff?
