While preparing for an ElasticSearch upgrade I checked the Upgrade assistant.
One (critical) issue was mentioned: Discovery configuration is required in production mode
Let’s have a look what the documentation has to mention:
Production deployments of Elasticsearch now require at least one of the following settings to be specified in the
elasticsearch.yml
configuration file:
discovery.seed_hosts
discovery.seed_providers
cluster.initial_master_nodes
discovery.zen.ping.unicast.hosts
discovery.zen.hosts_provider
The first three settings in this list are only available in versions 7.0 and above. If you are preparing to upgrade from an earlier version, you must set
discovery.zen.ping.unicast.hosts
ordiscovery.zen.hosts_provider
.
In our case we don’t want to form a multiple-node cluster. So we ignore the documentation above and instead change the discovery.type
to single-node.
For more information about when you might use this setting, see Single-node discovery.