Updating validation blocking single-AZ ES clusters when Zone Awareness is disabled

[jacob-hudson]

what

Removing errant validation preventing the creation of Amazon OpenSearch Service ElasticSearch (ES) or OpenSearch (OS) clusters which live in a single Available Zone on Amazon Web Services (AWS)

Simple Process:

• You merge this PR
• You release a new version
• We can create clusters which live in one AZ
• Everyone wins

why

Development and testing clusters may not want or need two or more Availability Zones for cost (among other reasons, but FinOps - saving money - is important)

references

#158

Identical errors in internal company environment

[milldr]

valid values for zone_awareness_config are only 2 and 3 for the Terraform resource. Why remove that check?

• terraform documentation: https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/elasticsearch_domain
• relevant module resource attribute:

  terraform-aws-elasticsearch/main.tf

  Lines 155 to 160 in 3125d5a

  	dynamic "zone_awareness_config" {
  	for_each = var.availability_zone_count > 1 && var.zone_awareness_enabled ? [true] : []
  	content {
  	availability_zone_count = var.availability_zone_count
  	}
  	}

[jacob-hudson]

valid values for zone_awareness_config are only 2 and 3 for the Terraform resource. Why remove that check?

• terraform documentation: https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/elasticsearch_domain
• relevant module resource attribute:

  terraform-aws-elasticsearch/main.tf

  Lines 155 to 160 in 3125d5a

  	dynamic "zone_awareness_config" {
  	for_each = var.availability_zone_count > 1 && var.zone_awareness_enabled ? [true] : []
  	content {
  	availability_zone_count = var.availability_zone_count
  	}
  	}

You guys do not pin module versions to TF versions, meaning we could need the latest module (eg for EBS GP3) and not care about which aws provider version

Maybe remove the check and let AWS respond with an error a la GraphQL?

[Nuru]

This seems unnecessary to me. I would need to see added testing before I would approve this.

Users should be able to set zone_awareness_enabled to false and leave availability_zone_count unset and defaulted to 2, or set to 2 if the configuration of the root module makes leaving it unset too difficult.

[jacob-hudson]

This seems unnecessary to me. I would need to see added testing before I would approve this.

Users should be able to set zone_awareness_enabled to false and leave availability_zone_count unset and defaulted to 2, or set to 2 if the configuration of the root module makes leaving it unset too difficult.

Working on this, give me a few

[jacob-hudson]

Interesting point:

Would there ever be a chance you would want Zone Awareness disabled with more than 1 AZ?

[Nuru]

INVALID TERRAFORM: Variable validation conditions can refer only to the containing variable.

[ManuelMueller1st]

Can't we add 1 as a valid count? This seems unnecessarily complex to me.