[SOLR-12845] Add a default cluster policy

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 8.6
• Component/s: AutoScaling
• Assignee: Andrzej Bialecki
• Reporter: Shalin Shekhar Mangar
• Created: 09/Oct/18 07:28
• Updated: 23/Apr/20 10:35
• Resolved: 22/Apr/20 15:48

Description

[~varunthacker] commented on SOLR-12739:

We should also ship with some default policies - "Don't allow more than one replica of a shard on the same JVM" , "Distribute cores across the cluster evenly" , "Distribute replicas per collection across the nodes"

This issue is about adding these defaults. I propose the following as default cluster policy:

# Each shard cannot have more than one replica on the same node if possible
{"replica": "<2", "shard": "#EACH", "node": "#ANY", "strict":false}
# Each collections replicas should be equally distributed amongst nodes
{"replica": "#EQUAL", "node": "#ANY", "strict":false} 
# All cores should be equally distributed amongst nodes
{"cores": "#EQUAL", "node": "#ANY", "strict":false}

Issue Links

• is blocked by: SOLR-12978 Autoscaling Suggester tries to test metrics for dead nodes
• is related to: SOLR-12739 Make autoscaling policy based replica placement the default strategy for placing replicas
• relates to: SOLR-13248 Autoscaling based replica placement is broken out of the box
• supercedes: SOLR-12826 Add a default policy to equally distribute replicas of a shard