I have a question relating to AWS RDS cluster and instance creation.
Environment
We recently experimented with:
Terraform v0.11.11
provider.aws v1.41.0
Background
Creating some AWS RDS databases. Our mission was that in some environment (e.g. staging) we may run fewer instances than in others (e.g. production.). With this in mind and not wanting to have totally different terraform files per environment we instead decided to specify the database resources just once and use a variable for the number of instances which is set in our staging.tf and production.tf files respectively for the number of instances.
Potentially one more "quirk" of our setup, is that the VPC in which the subnets exist is not defined in terraform, the VPC already existed via manual creation in the AWS console, so this is provided as a data provider and the subnets for the RDS are specific in terraform - but again this is dynamic in the sense that in some environments we might have 3 subnets (1 in each AZ), whereas in others perhaps we have only 2 subnets. Again to achieve this we used iteration as shown below:
Structure
|-/environments
-/staging
-staging.tf
-/production
-production.tf
|- /resources
- database.tf
Example Environment Variables File
dev.tf
terraform {
terraform {
backend "s3" {
bucket = "my-bucket-dev"
key = "terraform"
region = "eu-west-1"
encrypt = "true"
acl = "private"
dynamodb_table = "terraform-state-locking"
}
version = "~> 0.11.8"
}
provider "aws" {
access_key = "${var.access_key}"
secret_key = "${var.secret_key}"
region = "${var.region}"
version = "~> 1.33"
allowed_account_ids = ["XXX"]
}
module "main" {
source = "../../resources"
vpc_name = "test"
test_db_name = "terraform-test-db-dev"
test_db_instance_count = 1
test_db_backup_retention_period = 7
test_db_backup_window = "00:57-01:27"
test_db_maintenance_window = "tue:04:40-tue:05:10"
test_db_subnet_count = 2
test_db_subnet_cidr_blocks = ["10.2.4.0/24", "10.2.5.0/24"]
}
We came to this module based structure for environment isolation mainly due to these discussions:
https://github.com/hashicorp/terraform/issues/18632#issuecomment-412247266
https://github.com/hashicorp/terraform/issues/13700
https://www.terraform.io/docs/state/workspaces.html#when-to-use-multiple-workspaces
Our Issue
Initial resource creation works fine, our subnets are created, the database cluster starts up.
Our issues start the next time we subsequently run a terraform plan or terraform apply (with no changes to the files), at which point we see interesting things like:
An execution plan has been generated and is shown below.
Resource actions are indicated with the following symbols:
-/+ destroy and then create replacement
Terraform will perform the following actions:
module.main.aws_rds_cluster.test_db (new resource required)
id: "terraform-test-db-dev" => (forces new resource)
availability_zones.#: "3" => "1" (forces new resource)
availability_zones.1924028850: "eu-west-1b" => "" (forces new resource)
availability_zones.3953592328: "eu-west-1a" => "eu-west-1a"
availability_zones.94988580: "eu-west-1c" => "" (forces new resource)
and
module.main.aws_rds_cluster_instance.test_db (new resource required)
id: "terraform-test-db-dev" => (forces new resource)
cluster_identifier: "terraform-test-db-dev" => "${aws_rds_cluster.test_db.id}" (forces new resource)
Something about the way we are approaching this appears to be causing terraform to believe that the resource has changed to such an extent that it must destroy the existing resource and create a brand new one.
Config
variable "aws_availability_zones" {
description = "Run the EC2 Instances in these Availability Zones"
type = "list"
default = ["eu-west-1a", "eu-west-1b", "eu-west-1c"]
}
variable "test_db_name" {
description = "Name of the RDS instance, must be unique per region and is provided by the module config"
}
variable "test_db_subnet_count" {
description = "Number of subnets to create, is provided by the module config"
}
resource "aws_security_group" "test_db_service" {
name = "${var.test_db_service_user_name}"
vpc_id = "${data.aws_vpc.vpc.id}"
}
resource "aws_security_group" "test_db" {
name = "${var.test_db_name}"
vpc_id = "${data.aws_vpc.vpc.id}"
}
resource "aws_security_group_rule" "test_db_ingress_app_server" {
security_group_id = "${aws_security_group.test_db.id}"
...
source_security_group_id = "${aws_security_group.test_db_service.id}"
}
variable "test_db_subnet_cidr_blocks" {
description = "Cidr block allocated to the subnets"
type = "list"
}
resource "aws_subnet" "test_db" {
count = "${var.test_db_subnet_count}"
vpc_id = "${data.aws_vpc.vpc.id}"
cidr_block = "${element(var.test_db_subnet_cidr_blocks, count.index)}"
availability_zone = "${element(var.aws_availability_zones, count.index)}"
}
resource "aws_db_subnet_group" "test_db" {
name = "${var.test_db_name}"
subnet_ids = ["${aws_subnet.test_db.*.id}"]
}
variable "test_db_backup_retention_period" {
description = "Number of days to keep the backup, is provided by the module config"
}
variable "test_db_backup_window" {
description = "Window during which the backup is done, is provided by the module config"
}
variable "test_db_maintenance_window" {
description = "Window during which the maintenance is done, is provided by the module config"
}
data "aws_secretsmanager_secret" "test_db_master_password" {
name = "terraform/db/test-db/root-password"
}
data "aws_secretsmanager_secret_version" "test_db_master_password" {
secret_id = "${data.aws_secretsmanager_secret.test_db_master_password.id}"
}
data "aws_iam_role" "rds-monitoring-role" {
name = "rds-monitoring-role"
}
resource "aws_rds_cluster" "test_db" {
cluster_identifier = "${var.test_db_name}"
engine = "aurora-mysql"
engine_version = "5.7.12"
# can only request to deploy in AZ's where there is a subnet in the subnet group.
availability_zones = "${slice(var.aws_availability_zones, 0, var.test_db_instance_count)}"
database_name = "${var.test_db_schema_name}"
master_username = "root"
master_password = "${data.aws_secretsmanager_secret_version.test_db_master_password.secret_string}"
preferred_backup_window = "${var.test_db_backup_window}"
preferred_maintenance_window = "${var.test_db_maintenance_window}"
backup_retention_period = "${var.test_db_backup_retention_period}"
db_subnet_group_name = "${aws_db_subnet_group.test_db.name}"
storage_encrypted = true
kms_key_id = "${data.aws_kms_key.kms_rds_key.arn}"
deletion_protection = true
enabled_cloudwatch_logs_exports = ["audit", "error", "general", "slowquery"]
vpc_security_group_ids = ["${aws_security_group.test_db.id}"]
final_snapshot_identifier = "test-db-final-snapshot"
}
variable "test_db_instance_count" {
description = "Number of instances to create, is provided by the module config"
}
resource "aws_rds_cluster_instance" "test_db" {
count = "${var.test_db_instance_count}"
identifier = "${var.test_db_name}"
cluster_identifier = "${aws_rds_cluster.test_db.id}"
availability_zone = "${element(var.aws_availability_zones, count.index)}"
instance_class = "db.t2.small"
db_subnet_group_name = "${aws_db_subnet_group.test_db.name}"
monitoring_interval = 60
engine = "aurora-mysql"
engine_version = "5.7.12"
monitoring_role_arn = "${data.aws_iam_role.rds-monitoring-role.arn}"
tags {
Name = "test_db-${count.index}"
}
}
My question is, is there a way to achieve this so that terraform would not try to recreate the resource (e.g. ensure that the availability zones of the cluster and ID of the instance do not change each time we run terraform.
Turns out that simply by just removing the explicit availability zones definitions from the aws_rds_cluster and aws_rds_cluster_instance then this issue goes away and everything so far appears to work as expected. See also https://github.com/terraform-providers/terraform-provider-aws/issues/7307#issuecomment-457441633
Related
I'm trying to create an aws_ssm_parameter in 2 regions from within 1 resource block as I need the writer endpoint in both eu-central-1 and eu-west-1 available from SSM.
Currently I'm doing it like this:
resource "aws_ssm_parameter" "primary_writer_endpoint" {
name = "/aurora/${var.environment}-${var.service_name}-primary-cluster/writer-endpoint"
type = "String"
value = aws_rds_cluster.primary.endpoint
overwrite = true
}
resource "aws_ssm_parameter" "primary_writer_endpoint_replica_region" {
name = "/aurora/${var.environment}-${var.service_name}-primary-cluster/writer-endpoint"
type = "String"
value = aws_rds_cluster.primary.endpoint
overwrite = true
provider = aws.replica
}
as I declared 2 providers:
provider "aws" {
region = "eu-central-1"
}
provider "aws" {
alias = "replica"
region = "eu-west-1"
}
Is there a cleaner way to do this, e.g. for each provider, or create a map of the providers?
Would be great to do this cleaner.
Would be grateful for any assistance, I thought I had nailed this one when I stumbled across the following link ...
Creating a resource group with terraform in azure: Cannot find resource group directly after creating it
However, the next stage of my code is still failing...
Error: Code="ResourceGroupNotFound" Message="Resource group 'ShowTell' could not be found
# We strongly recommend using the required_providers block to set the
# Azure Provider source and version being used
terraform {
required_providers {
azurerm = {
source = "hashicorp/azurerm"
version = "=2.64.0"
}
}
}
# Configure the Microsoft Azure Provider
provider "azurerm" {
features {}
}
variable "resource_group_name" {
type = string
default = "ShowTell"
description = ""
}
# Create your resource group
resource "azurerm_resource_group" "example" {
name = var.resource_group_name
location = "UK South"
}
# Should be accessible from LukesContainer.uksouth.azurecontainer.io
resource "azurerm_container_group" "LukesContainer" {
name = "LukesContainer"
location = "UK South"
resource_group_name = "${var.resource_group_name}"
ip_address_type = "public"
dns_name_label = "LukesContainer"
os_type = "Linux"
container {
name = "hello-world"
image = "microsoft/aci-helloworld:latest"
cpu = "0.5"
memory = "1.5"
ports {
port = "443"
protocol = "TCP"
}
}
container {
name = "sidecar"
image = "microsoft/aci-tutorial-sidecar"
cpu = "0.5"
memory = "1.5"
}
tags = {
environment = "testing"
}
}
In order to create an implicit dependency you must refer directly to the object that the dependency relates to. In your case, that means deriving the resource group name from the resource group object itself, rather than from the variable you'd used to configure that object:
resource "azurerm_container_group" "LukesContainer" {
name = "LukesContainer"
location = "UK South"
resource_group_name = azurerm_resource_group.example.name
# ...
}
With the configuration you included in your question, both the resource group and the container group depend on var.resource_group_name but there was no dependency between azurerm_container_group.LukesContainer and azurerm_resource_group.example, and so Terraform is therefore free to create those two objects in either order.
By deriving the container group's resource group name from the resource group object you tell Terraform that the resource group must be processed first, and then its results used to populate the container group.
I inherited a codebase with all providers stored inside modules and am having a lot of trouble moving the providers out so that I can remove the resources created from modules.
The current design violates the rules outlined here: https://www.terraform.io/docs/configuration/providers.html and makes removing modules impossible.
My understanding of the migration steps is:
Create a provider for use at the top-level
Update module resources to use providers stored outside of the module
Remove module (with top-level provider persisting)
Example module
An example /route53-alias-record/main.ts is:
variable "evaluate_target_health" {
default = true
}
data "terraform_remote_state" "env" {
backend = "s3"
config = {
bucket = "<bucket>"
key = "infra-${var.environment}-${var.target}.tfstate"
region = "<region>"
}
}
provider "aws" {
region = data.terraform_remote_state.env.outputs.region
allowed_account_ids = data.terraform_remote_state.env.outputs.allowed_accounts
assume_role {
role_arn = data.terraform_remote_state.env.outputs.aws_account_role
}
}
resource "aws_route53_record" "alias" {
zone_id = data.terraform_remote_state.env.outputs.public_zone_id
name = var.fqdn
type = "A"
alias {
name = var.alias_name
zone_id = var.zone_id
evaluate_target_health = var.evaluate_target_health
}
}
Starting usage
module "api-dns-alias" {
source = "../environment/infra/modules/route53-alias-record"
environment = "${var.environment}"
zone_id = "${module.service.lb_zone_id}"
alias_name = "${module.service.lb_dns_name}"
fqdn = "${var.environment}.example.com"
}
Provider overriding
## Same as inside module
provider "aws" {
region = data.terraform_remote_state.env.outputs.region
allowed_account_ids = data.terraform_remote_state.env.outputs.allowed_accounts
assume_role {
role_arn = data.terraform_remote_state.env.outputs.aws_account_role
}
}
module "api-dns-alias" {
source = "../environment/infra/modules/route53-alias-record"
environment = "${var.environment}"
zone_id = "${module.service.lb_zone_id}"
alias_name = "${module.service.lb_dns_name}"
fqdn = "${var.environment}.example.com"
providers = {
aws = aws ## <-- pass in explicitly
}
}
I was able to safely deploy with the providers set, but I do not believe that they are being used inside the module, which means the handshake still fails when I remove the module and the resources cannot be deleted.
I am looking for the steps needed to migrate to an outside provider so that I can safely remove resources.
I am currently working with terraform 0.12.24
I'm trying to keep AWS EBS volume as a persistent data-store, every week my AMI changes so I have to spin-up new VM in aws. At this time I'm expecting my volume to detach from the old VM and attach to a new VM without destroying the EBS volume and data.
resource "aws_instance" "my_instance" {
count = var.instance_count
ami = lookup(var.ami,var.aws_region)
instance_type = var.instance_type
key_name = aws_key_pair.terraform-demo.key_name
subnet_id = aws_subnet.main-public-1.id
// user_data = "${file("install_apache.sh")}"
tags = {
Name = "Terraform-${count.index + 1}"
Batch = "5AM"
}
}
variable "instances" {
type = map
default = {
"xx" = "sss-console"
"4xx" = "sss-upload-port"
"xxx" = "sss"
}
}
resource "aws_kms_key" "cmp_kms" {
description = "ssss-ebsencrypt"
tags = local.all_labels
}
resource "aws_ebs_volume" "volumes" {
count = var.instance_count
availability_zone = element(aws_instance.my_instance.*.availability_zone, count.index )
encrypted = true
kms_key_id = aws_kms_key.cmp_kms.arn
size = local.volume_size
type = local.volume_type
iops = local.volume_iops
// tags = merge(var.extra_labels, map("Name", "${var.cell}-${element(local.volume_name, count.index)}"))
lifecycle {
// prevent_destroy = true
ignore_changes = [kms_key_id, instance_id]
}
}
resource "aws_volume_attachment" "volumes-attachment" {
depends_on = [aws_instance.my_instance, aws_ebs_volume.volumes]
count = var.instance_count
device_name = "/dev/${element(local.volume_name, count.index)}"
volume_id = element(aws_ebs_volume.volumes.*.id, count.index)
instance_id = element(aws_instance.my_instance.*.id, count.index)
force_detach = true
}
ERROR on terraform apply
Error: Unsupported attribute
on instance.tf line 71, in resource "aws_ebs_volume" "volumes":
71: ignore_changes = [kms_key_id, instance_id]
This object has no argument, nested block, or exported attribute named
"instance_id".
earlier the same code use to work with terraform v0.11 but it's not working with v0.12. what is the replacement for this or how can we re-attach EBS to a different machine without destroying it?
As per terraform documentation, they do not expose any attribute named as instance_id for resource aws_ebs_volume.
For reference: https://www.terraform.io/docs/providers/aws/d/ebs_volume.html.
You can specify the instance_id at the time of volume attachment using resource
aws_volume_attachment.
You can refer the answer given in https://gitter.im/hashicorp-terraform/Lobby?at=5ab900eb2b9dfdbc3a237e36 for more information.
I'm starting to use (and learn) terraform, for now, I need to create multiple DO droplets and attach them to the aws route53 zone, what I'm trying to do:
My DO terraform file:
# Configure the DigitalOcean Provider
provider "digitalocean" {
token = var.do_token
}
# Create a new tag
resource "digitalocean_tag" "victor" {
name = "victor-fee1good22"
}
resource "digitalocean_droplet" "web" {
count = 2
image = var.do_config["image"]
name = "web-${count.index}"
region = var.do_config["region"]
size = var.do_config["size"]
ssh_keys = [var.public_ssh_key, var.pv_ssh_key]
tags = [digitalocean_tag.victor.name]
}
My route53 file:
provider "aws" {
version = "~> 2.0"
region = "us-east-1"
access_key = var.aws_a_key
secret_key = var.aws_s_key
}
data "aws_route53_zone" "selected" {
name = "devops.rebrain.srwx.net"
}
resource "aws_route53_record" "www" {
сount = length(digitalocean_droplet.web)
zone_id = data.aws_route53_zone.selected.zone_id
name = "web_${count.index}"
type = "A"
ttl = "300"
records = [digitalocean_droplet.web[count.index].ipv4_address]
}
But I always get The "count" object can be used only in "resource" and "data" blocks, and only
when the "count" argument is set. error, what did I wrong?
Thanks!
UPDATE:
I've resolved this one like — add сount = 2 instead of сount = length(digitalocean_droplet.web)
It works but would be better to have the dynamic variable instead of constant count. :)
you want to get number of services, that not yet created. Terraform couldn't do that.
As I think simplest way use common var with the number of droplets.
resource "digitalocean_droplet" "test" {
count = var.number_of_vps
image = "ubuntu-18-04-x64"
name = "test-1"
region = data.digitalocean_regions.available.regions[0].slug
size = "s-1vcpu-1gb"
}
resource "aws_route53_record" "test" {
count = var.number_of_vps
zone_id = data.aws_route53_zone.primary.zone_id
name = "${local.login}-${count.index}.${data.aws_route53_zone.primary.name}"
type = "A"
ttl = "300"
records = [digitalocean_droplet.test[count.index].ipv4_address]
}
This trick helped - https://github.com/hashicorp/terraform/issues/12570#issuecomment-291517239
resource "aws_route53_record" "dns" {
count = "${length(var.ips) > 0 ? length(var.domains) : 0}"
// ...
}