[SOLR-11026] Policy can suggest more operations than necessary

• Type: Sub-task
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 7.1, 8.0
• Component/s: AutoScaling, SolrCloud
• Labels: autoscaling
• Assignee: Noble Paul
• Reporter: Shalin Shekhar Mangar
• Created: 07/Jul/17 08:08
• Updated: 05/Feb/18 04:33
• Resolved: 18/Jul/17 09:52

Description

To reproduce:

./bin/solr -e cloud -noprompt

Add policy and preferences:

{ 'set-cluster-policy': [      {'cores':'<10', 'node':'#ANY'},      {'replica':'<2', 'shard': '#EACH', 'node': '#ANY'},      {'nodeRole':'overseer', 'replica':0}    ],
'set-cluster-preferences': [{'minimize': 'cores'}]
}

Add a trigger:

{
	'set-trigger': {
		'name' : 'node_added_trigger',
		'event' : 'nodeAdded',
		'waitFor' : '1s'
	}
}

Shutdown a node (so only 1 is live)

./bin/solr stop -p 7574

Add a collection with 2 shards, 1 replica

http://localhost:8983/solr/admin/collections?action=create&name=test&replicationFactor=1&numShards=2&maxShardsPerNode=2&wt=json

The diagnostic output at this point is:

{
    "responseHeader": {
        "status": 0,
        "QTime": 23
    },
    "diagnostics": {
        "sortedNodes": [
            {
                "node": "127.0.1.1:8983_solr",
                "cores": 2
            }
        ],
        "violations": []
    },
    "WARNING": "This response format is experimental.  It is likely to change in the future."
}

Start the other node that we had shutdown earlier:

"bin/solr" start -cloud -p 7574 -s "example/cloud/node2/solr" -z localhost:9983

The trigger kicks in but both cores are moved to the new node. Diagnostics output at steady state:

{
    "responseHeader": {
        "status": 0,
        "QTime": 23
    },
    "diagnostics": {
        "sortedNodes": [
            {
                "node": "127.0.1.1:7574_solr",
                "cores": 2
            },
            {
                "node": "127.0.1.1:8983_solr",
                "cores": 0
            }
        ],
        "violations": []
    },
    "WARNING": "This response format is experimental.  It is likely to change in the future."
}