Migrate from Helm to Operator (es7 to es8)

[mattiashem]

I have done some work migrating from the helmchart to the operator.
Wrote a blogpost here if anyone want to try it.

I hade to disable some security to make it work but when you have completed the migration, you should be able to turn them back.

Steps are 9 "easy" step ! :-)

1. Install the operator
2. Deploy a cluster using the operator (We will use the certs from this install )
3. Turn the operator of
4. Turn ALLA elasticnodes down by changing replicas in statefulset
5. Patch the current elasticsearch statefulset to use TLS and elasticsearch 8
6. Start the current Elasticsearch nodes up and wait until they form a cluster
7. Start the new elasticsearch nodes from the operator on and they will join the cluster
8. Migrate data from the old nodes over to the new
9. Delete old helmchart

Added all the code in the blog.

https://lifeandshell.com/blog/migrate-elasticsearch-helm-to-elasticsearch-operator/index.html

[mattiashem]

      discovery.seed_hosts:
         - elasticsearch-master-headless
         - elasticsearch-es-master
      cluster.initial_master_nodes: 
         - elasticsearch-master-0
         - elasticsearch-master-1
         - elasticsearch-master-2
         - elasticsearch-es-master-0
         - elasticsearch-es-master-2
         - elasticsearch-es-master-3 

Update the config to add the new master also