Replica number changes on new deployments

[gruntwork-support]

This message was extracted from a discussion that originally took place in Gruntwork Community Slack. Names and URLs have been removed where appropriate

From a customer

Hi,

When using HPA like :

autoscaler = {
  enable          = true
  min_replicas    = 6
  max_replicas    = 150
  avg_cpu_util    = 15
  avg_memory_util = 0
}

No matter what the current REPLICA number the deployment set it to 6.
My expectation is that the REPLICA will not change as a result of the deployment.

Please advice

[gruntwork-support]

From a grunt

Hey person,

I've asked for some guidance on this, and here's some details:

The deployment is getting reset by the helm chart, specifically the replicaCount input. HPA works by overwriting the replica count of the deployment, but there's no ignore_changes terraform type behaviour in helm. Therefore, the helm chart just overwrites the deployment every time based on what is in the helm chart.

It might best to use a run_cmd call in terragrunt that uses kubectl to get the current value of the replica count on the Deployment and update the input value to use that.

[gruntwork-support]

From a customer

Thanks