We have an ecommerce .net website runs on azure which contains 4 services, website services are (i think they're called paas) "admin","api","web" and "solr" ,we use solr for product search. "admin" runs cron job for every 1 hour and updates solr.
We were using single instance on azure and when i deploy all our four apps , there wasn't any problem. Beginning of the last week we decided to run 3 instance instead of 1 and use a load balancer in front of them, after that things get complicated.
Now when i publish my app service which updates solr, app service runs on all of the three instances and every instance tries to update solr. My solution was seperating solr and other services but unfortunately i didn't allow to do it. In this situation every instance updates solr and which solr they're updating i don't know because simply we have 3 instances and all instances have 4 apps inside(api,admin,web,solr).
I solved the update problem by using website_instance_id environment variable, in the startup i allow only one instance to run the update so 3x update problem is solved but again i don't know which solr will be updated after this. SolrCloud solves that? I hope I was able to explain myself.