WIP plan please fix:
- Install & test elasticsearch 5.6.14 to deployment-prep
- T215931 Upgrade codfw to 5.6.14 (rolling restart)
- switch traffic to codfw (for testing)
- T215931 Upgrade eqiad to 5.6.14
- T216052: Upgrade logstash to 5.6.14 (so that we assure compatibility and api-feature-usage can still be populated once the search cluster is running 6.5)
- In parallel merge the es6 branch for Elastica and CirrusSearch to master and wait for the train to be stable enough when we are sure it can't be rolled back.
- ES6 compat code should be running on 1.33.0-wmf.19
- T199791 release plugins for 6.5.4
- Install & test elasticsearch 6.5.4 to deployment-prep
- Upgrade codfw to 6.5.4 (rolling restart)
- Switch search related traffic to codfw
- Upgrade eqiad to 6.5.4 (rolling restart)
- Switch search related traffic back to eqiad