Update quickstart with new solr command

[skorper]

I was running through the quickstart and found the ZK_HOST environment variable wasn't being used by the solr container, resulting in failure. By updating to SDAP_ZK_SERVICE_HOST the solr container ran successfully.

[RKuttruff]

This is odd, my existing deployment with Docker uses ZK_HOST without issue. What kind of error were you seeing?

[skorper]

I can try to recreate the issue a bit later. But in summary, the solr container failed to launch because it could not find the zookeeper host. It seemed like ZK_HOST was being totally ignored. To confirm this, I changed the port in ZK_HOST and noticed the solr container was still attempting to access zookeeper at the old port. When inspecting the solr container I noticed there were other ZK related env vars and played around with it until I found something that worked. I'll post a follow-up with logs and more details soon

[RKuttruff]

Thinking on this, it may be a good idea to provide both commands and inform the user that if one does not work, try the other.

[ngachung]

According to this thread https://lists.apache.org/thread/3n2tdsll202z644r4w8x8wb6c0f3o1n0 this change resolved the issue user was encountering, so I think we should merge this.