Waiting for Solr to load By current state of the art, we cannot enforce an ordered start sequence of service containers directly, neither in Docker Swarm nor in Kubernetes. (Maybe there is a standard solution for that via a specialized orchestraton service)

Now, imagine we want to have a Solr instance with considerable amount of data, and want to get it ready before other services can start their work.

What is the best way to verify this status?

It seems for example that calling and validating the expected list of loaded collections is not enough:

/solr/admin/collections?action=LIST


Other ideas?
This has worked - the following query has to return content-type application/xml:

 /solr/COLLECTION/select?q=*:*&amp;rows=0