Terraform (provider AWS) - Auto Scaling group doesn't take effect on a launch template change

[ghost]

This issue was originally opened by @vivekyad4v as hashicorp/terraform#23685. It was migrated here as a result of the provider split. The original body of the issue is below.

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Unable to make launch template work with ASGs while using launch templates, it works with Launch Configuration using a small hack i.e by interpolating the launch configuration name in ASG resource but it doesn't work with launch templates.
ASG uses the latest version to launch new instances but doesn't change anything w.r.t to pre-running instances inspite of a change in launch template.

I understand that this is sort of expected but do we have any workaround to make launch templates work with ASG or we need to stick to launch configuration itself?

resource "aws_launch_template" "lc_ec2" {
  image_id = "${var.ami_id}"
  instance_type = "${var.app_instance_type}"
  key_name = "${var.orgname}_${var.environ}_kp"
  vpc_security_group_ids = ["${aws_security_group.sg_ec2.id}"]
  user_data = "${base64encode(var.userdata)}"
  block_device_mappings {
    device_name = "/dev/xvdv"
    ebs {
      volume_size = 15
    }
  }
  iam_instance_profile {
    name = "${var.orgname}_${var.environ}_profile"
  }
  lifecycle {
    create_before_destroy = true
  }

  tag_specifications {
    resource_type = "instance"
    tags = "${merge(map("Name", format("%s-%s-lc-ec2", var.orgname, var.environ)), var.tags)}"
    } 
  tag_specifications {
    resource_type = "volume"
   tags = "${merge(map("Name", format("%s-%s-lc-ec2-volume", var.orgname, var.environ)), var.tags)}"
    }
  tags = "${merge(map("Name", format("%s-%s-lc-ec2", var.orgname, var.environ)), var.tags)}"
}

resource "aws_autoscaling_group" "asg_ec2" {
    name = "${var.orgname}-${var.environ}-asg-ec2-${aws_launch_template.lc_ec2.name}"

    vpc_zone_identifier = ["${data.aws_subnet.private.*.id}"]
    min_size  = 1
    desired_capacity  = 1
    max_size  = 1
    target_group_arns = ["${aws_lb_target_group.alb_tg.arn}"]
    default_cooldown= 100
    health_check_grace_period = 100
    termination_policies = ["ClosestToNextInstanceHour", "NewestInstance"]
    health_check_type="ELB"
    launch_template = {
      id = "${aws_launch_template.lc_ec2.id}"
      version = "$$Latest"
   }  
      lifecycle {
    create_before_destroy = true
  }

  tags = [
    {
      key                 = "Name"
      value               = "${var.orgname}"
      propagate_at_launch = true
    },
    {
      key                 = "Environ"
      value               = "${var.environ}"
      propagate_at_launch = true
    }
  ]
}

[sanspace]

Did you find a workaround for this, @vivekyad4v?

[nbetm]

I run into the same problem today!

[liath]

For others coming along late to this question, there's discussion of a fix (and a potential workaround!) here: #13785 (comment)

[liath]

Even better, Instance Refresh support was added by #16678 so this can probably be closed!

[bflad]

Auto Scaling Group instance refresh was indeed introduced with version 3.22.0 of the Terraform AWS Provider last week. Closing as this functionality, provided by AWS, would be the recommended solution in this case.

If you're looking for further general assistance, please note that we use GitHub issues in this repository for tracking bugs and enhancements with the Terraform AWS Provider codebase rather than for questions. While we may be able to help with certain simple problems here it's generally better to use the HashiCorp Community Forums where there are far more people ready to help, whereas the GitHub issues here are generally monitored only by a few maintainers and dedicated community members interested in code development of the Terraform AWS Provider itself.

[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!