Upgrade epics services and tools to elastic8

[georgweiss]

• Update all Epics middle layer services ( and the few clients which directly query the elastic backend) to uses elastic 8.
• Describe how to copy data from existing elastic 7 installation to new elastic 8 server.

[kasemir]

copy data from existing elastic 7 installation to new elastic 8

Related: Copying from elastic 6 to elastic 7.
Assume you have an older elastic 6 server on host ..arch2, and a new elastic 7 server on host arch3:

curl http://ics-srv-arch2:9200/_cat/indices?v
curl http://ics-srv-arch3:9200/_cat/indices?v

On the new host, allow reading from the old 'remote' by adding this to the config/elasticsearch.yml:

# Prevent the node from trying to form a cluster
discovery.type: single-node

# If you want to import data from old server,
# allow 'reindex' to copy data from there
reindex.remote.whitelist: ["ics-srv-arch2:9200"]

Then import data from the old server via 'reindex',
https://www.elastic.co/guide/en/cloud/current/ec-migrate-data.html#ec-reindex-remote :

curl -H 'Content-Type: application/json' -XPOST http://ics-srv-arch3:9200/_reindex?pretty -d'
{
  "source": {
    "remote" : { "host" : "http://ics-srv-arch2:9200" },
    "index": "cf_tags"
  },
  "dest": {
    "index": "cf_tags"
  }
}'


curl -H 'Content-Type: application/json' -XPOST http://ics-srv-arch3:9200/_reindex?pretty -d'
{
  "source": {
    "remote" : { "host" : "http://ics-srv-arch2:9200" },
    "index": "cf_properties"
  },
  "dest": {
    "index": "cf_properties"
  }
}'

curl -H 'Content-Type: application/json' -XPOST http://ics-srv-arch3:9200/_reindex?pretty -d'
{
  "source": {
    "remote" : { "host" : "http://ics-srv-arch2:9200" },
    "index": "channelfinder"
  },
  "dest": {
    "index": "channelfinder"
  }
}'