aws_db_instance parameter_group_name Ignored

[hashibot]

This issue was originally opened by @dgarstang as hashicorp/terraform#17031. It was migrated here as a result of the provider split. The original body of the issue is below.

---

Following code:

resource "aws_db_instance" "alpha" {
  allocated_storage    = 300
  storage_type         = "gp2"
  engine               = "mysql"
  engine_version       = "5.5.46"
  instance_class       = "db.m4.large"
  identifier           = "${var.name}"
  db_subnet_group_name = "default"
  parameter_group_name = "allow-triggers"
  snapshot_identifier  = "${var.rds_snapshot_name}"
  skip_final_snapshot  = true
  tags = {
    Name = "${var.name}"
  }
}

When running apply, output displays:

parameter_group_name:                           "allow-triggers"

However, when I look at the RDS instance in the AWS cli, it shows:

Parameter group
default.mysql5.5 (in-sync)

Seems that parameter_group_name is completely ignored.
Terraform v0.11.1

[atsushi-ishibashi]

because snapshot_identifier is set

[dgarstang]

I tried creating an RDS instance from a snapshot in the AWS console. I was not asked for a db parameter group. The parameter group used was the default, not the parameter group used by the original snapshot. Is there some way to set this in terraform?

[atsushi-ishibashi]

Could you try to specify parameter_group_name = "allow-triggers" after terraform apply then terraform apply again?

[dgarstang]

No I don't really think that's a viable option.

[atsushi-ishibashi]

I'll submit PR to fix it because parameter_group_name is ignored completely as you said but if you'd like to work well with the current version, I suggest the above way or running terraform apply two times may work.

[bflad]

In version 1.33.0 of the AWS provider, likely releasing later today, the aws_db_instance will now correctly apply parameter_group_name on resource creation when using snapshot_identifier. Please note though that it will still be in pending-reboot state, which will also be fixed shortly. You can track any of these for the pending-reboot issue: #218, #1494, #1510

[ghost]

I'm going to lock this issue because it has been closed for 30 days ⏳. This helps our maintainers find and focus on the active issues.

If you feel this issue should be reopened, we encourage creating a new issue linking back to this one for added context. Thanks!