I've deployed an ELK stack to AWS ECS with terraform. All was running nicely for a few weeks, but 2 days ago I had to restart the instance.
Sadly, the new instance did not rely on the existing volume to mount the root block device. So all my elasticsearch data are no longer available to my Kibana instance.
Datas are still here, on previous volume, currently not used.
So I tried many things to get this volume attached at "dev/xvda" but without for exemple:
I am using an aws_autoscaling_group with an aws_launch_configuration.
resource "aws_launch_configuration" "XXX" {
name = "XXX"
image_id = data.aws_ami.latest_ecs.id
instance_type = var.INSTANCE_TYPE
security_groups = [var.SECURITY_GROUP_ID]
associate_public_ip_address = true
iam_instance_profile = "XXXXXX"
spot_price = "0.04"
lifecycle {
create_before_destroy = true
}
user_data = templatefile("${path.module}/ecs_agent_conf_options.tmpl",
{
cluster_name = aws_ecs_cluster.XXX.name
}
)
//The volume i want to reuse was created with this configuration. I though it would
//be enough to reuse the same volume. It doesn't.
root_block_device {
delete_on_termination = false
volume_size = 50
volume_type = "gp2"
}
}
resource "aws_autoscaling_group" "YYY" {
name = "YYY"
min_size = var.MIN_INSTANCES
max_size = var.MAX_INSTANCES
desired_capacity = var.DESIRED_CAPACITY
health_check_type = "EC2"
availability_zones = ["eu-west-3b"]
launch_configuration = aws_launch_configuration.XXX.name
vpc_zone_identifier = [
var.SUBNET_1_ID,
var.SUBNET_2_ID]
}
Do I miss something obvious about this?
Sadly, you cannot attach a volume as a root volume to an instance.
What you have to do is create a custom AMI based on your volume. This involves creating a snapshot of the volume followed by construction of the AMI:
In terraform, there is aws_ami specially for that purpose.
The following terraform script exemplifies the process in three steps:
provider "aws" {
# your data
}
resource "aws_ebs_snapshot" "snapshot" {
volume_id = "vol-0ff4363a40eb3357c" # <-- your EBS volume ID
}
resource "aws_ami" "my" {
name = "my-custom-ami"
virtualization_type = "hvm"
root_device_name = "/dev/xvda"
ebs_block_device {
device_name = "/dev/xvda"
snapshot_id = aws_ebs_snapshot.snapshot.id
volume_type = "gp2"
}
}
resource "aws_instance" "web" {
ami = aws_ami.my.id
instance_type = "t2.micro"
# key_name = "<your-key-name>"
tags = {
Name = "InstanceFromCustomAMI"
}
}