From Change the index name | Filebeat Reference [8.6] | Elastic
output.elasticsearch.index: "customname-%{[agent.version]}"
setup.template.name: "customname"
setup.template.pattern: "customname-%{[agent.version]}"
From filebeat.reference.yml | Filebeat Reference [8.6] | Elastic (abridged):
output.elasticsearch:
index: "filebeat-%{[agent.version]}"
setup.template.name: "filebeat-%{[agent.version]}"
setup.template.pattern: "filebeat-%{[agent.version]}"
There is a key difference here that is not explained by the docs. In the first example, the setup.template.name is not suffixed with the agent (filebeat) version, whereas in the second case, it is. As the agent versions are upgraded over time, this causes a difference in behavior where either (scenario 1) the same-named template is overwritten or (scenario 2) a new index template is created for each version.
Is it possible these two docs sources could be reconciled?