We're currently porting some of our CloudFormation templates to Terraform. In one of these templates we use a custom resource with a Lambda function.
The purpose of the function is to assume a role in our main AWS account; where R53 DNS is managed, and add a newly generated CloudFront dns there.
I am wondering if there's a way to do this in terraform, such that:
create the cloudfront resource, alb, etc on the dev/qa/prod accounts
add the r53 recordset to the main account
All within the same terraform plan. Can I choose an IAM role when creating a resource? Or choose the account where the resource should be created?
The only reference I have found is here
You can configure multiple providers ( one per account in your case) and create an alias for each. Then you will need to specify the provider for each ressource. Example:
provider "aws" {
region = "eu-west-1"
profile = "profile1"
alias = "account1"
}
provider "aws" {
region = "eu-west-1"
profile = "profile2"
alias = "account2"
}
resource "aws_lambda_function" "function1" {
provider = "aws.account1" // will be created in account 1
...
}
resource "aws_lambda_function" "function2" {
provider = "aws.account2" // will be created in account 2
...
}
Related
Based on this comment I wanted to give #Davos the opportunity to supply his answer to this question:
can you point at a good example of this (cross) account deployment setup? I am using the .aws/config and ./aws/credentials entries of another account, and specifying AWS_PROFILE=dev_admin for example, but resource owners are still showing as the main org's Management Account #. I've had no luck with the provider "profile" either...
I'm not aware of any kind of comprehensive tutorial for cross-account deployment.
AWS Terraform provider has options such as profile where we can specify which profile should be used from our ~/.aws/config file. Moreover, the provider can have a assume_role in which case a certain role will be assumed to create resources, although this can be necessary only we would want to use the same user and assume a role in another account.
We can have multiple providers in the same project. Each provider can use credentials for different users in different accounts. Each resource can specify which provider to use, so it will be provisioned in that specific account.
Bringing this all together, we can have the following example:
~/.aws/credentials file:
[default]
aws_access_key_id=ACCESS_KEY
aws_secret_access_key=SECRET_KEY
[user1]
aws_access_key_id=ACCESS_KEY
aws_secret_access_key=SECRET_KEY
~/.aws/config file:
[default]
region=us-west-1
output=json
[profile user1]
region=us-east-1
output=text
Terraform code:
# Default provider, it will use the credentials for the default profile and it will provision resources in the default account
provider "aws" {
region = "us-west-1"
}
# Provider for another account, it will use the credentials for profile user1 and it will provision resources in the secondary account
provider "aws" {
alias = "account1"
region = "us-east-1"
profile = "user1"
}
# No provider is explicitly specified, this will use the default provider
# It will be deployed in the default account
resource "aws_vpc" "default_vpc" {
cidr_block = "10.0.0.0/16"
}
# Provider is explicitly specified, so this will go into secondary account
resource "aws_vpc" "another_vpc" {
provider = aws.account1
cidr_block = "10.0.0.0/16"
}
Obviously, the state will be kept in a single place, which can be a bucket in any of the accounts.
I just created a new AWS account using Terraform aws_organizations_account module. What I am now trying to do is to create ressources into that new account. I guess I would need the account_id of the new AWS account to do that so I stored it into a new output variable but after that I have no idea how can I create a aws_s3_bucket for example
provider.tf
provider "aws" {
region = "us-east-1"
}
main.tf
resource "aws_organizations_account" "account" {
name = "tmp"
email = "first.last+tmp#company.com"
role_name = "myOrganizationRole"
parent_id = "xxxxx"
}
## what I am trying to create inside that tmp account
resource "aws_s3_bucket" "bucket" {}
outputs.tf
output "account_id" {
value = aws_organizations_account.account.id
sensitive = true
}
You can't do this the way you want. You need entire, account creation pipeline for that. Roughly in the pipeline you would have two main stages:
Create your AWS Org and member accounts.
Assume role from the member accounts, and run your TF code for these accounts to create resources.
There are many ways of doing this, and also there are many resources on this topic. Some of them are:
How to Build an AWS Multi-Account Strategy with Centralized Identity Management
Setting up an AWS organization from scratch with Terraform
Terraform on AWS: Multi-Account Setup and Other Advanced Tips
Apart from those, there is also AWS Control Tower, which can be helpful in setting up initial multi-account infrastructure.
I've been looking for a way to be able to deploy to multiple AWS accounts simultaneously in Terraform and coming up dry. AWS has the concept of doing this with Stacks but I'm not sure if there is a way to do this in Terraform? If so what would be some solutions?
You can read more about the Cloudformation solution here.
You can define multiple provider aliases which can be used to run actions in different regions or even different AWS accounts.
So to perform some actions in your default region (or be prompted for it if not defined in environment variables or ~/.aws/config) and also in US East 1 you'd have something like this:
provider "aws" {
# ...
}
# Cloudfront ACM certs must exist in US-East-1
provider "aws" {
alias = "cloudfront-acm-certs"
region = "us-east-1"
}
You'd then refer to them like so:
data "aws_acm_certificate" "ssl_certificate" {
provider = aws.cloudfront-acm-certs
...
}
resource "aws_cloudfront_distribution" "cloudfront" {
...
viewer_certificate {
acm_certificate_arn = data.aws_acm_certificate.ssl_certificate.arn
...
}
}
So if you want to do things across multiple accounts at the same time then you could assume a role in the other account with something like this:
provider "aws" {
# ...
}
# Assume a role in the DNS account so we can add records in the zone that lives there
provider "aws" {
alias = "dns"
assume_role {
role_arn = "arn:aws:iam::ACCOUNT_ID:role/ROLE_NAME"
session_name = "SESSION_NAME"
external_id = "EXTERNAL_ID"
}
}
And refer to it like so:
data "aws_route53_zone" "selected" {
provider = aws.dns
name = "test.com."
}
resource "aws_route53_record" "www" {
provider = aws.dns
zone_id = data.aws_route53_zone.selected.zone_id
name = "www.${data.aws_route53_zone.selected.name"
...
}
Alternatively you can provide credentials for different AWS accounts in a number of other ways such as hardcoding them in the provider or using different Terraform variables, AWS SDK specific environment variables or by using a configured profile.
I would recommend also combining your solution with Terraform workspaces:
Named workspaces allow conveniently switching between multiple
instances of a single configuration within its single backend. They
are convenient in a number of situations, but cannot solve all
problems.
A common use for multiple workspaces is to create a parallel, distinct
copy of a set of infrastructure in order to test a set of changes
before modifying the main production infrastructure. For example, a
developer working on a complex set of infrastructure changes might
create a new temporary workspace in order to freely experiment with
changes without affecting the default workspace.
Non-default workspaces are often related to feature branches in
version control. The default workspace might correspond to the
"master" or "trunk" branch, which describes the intended state of
production infrastructure. When a feature branch is created to develop
a change, the developer of that feature might create a corresponding
workspace and deploy into it a temporary "copy" of the main
infrastructure so that changes can be tested without affecting the
production infrastructure. Once the change is merged and deployed to
the default workspace, the test infrastructure can be destroyed and
the temporary workspace deleted.
AWS S3 is in the list of the supported backends.
It is very easy to use (similar to working with git branches) and combine it with the selected AWS account.
terraform workspace list
dev
* prod
staging
A few references regarding configuring the AWS provider to work with multiple account:
https://terragrunt.gruntwork.io/docs/features/work-with-multiple-aws-accounts/
https://assets.ctfassets.net/hqu2g0tau160/5Od5r9RbuEYueaeeycUIcK/b5a355e684de0a842d6a3a483a7dc7d3/devopscon-V2.1.pdf
I have an infrastructure I'm deploying using Terraform in AWS. This infrastructure can be deployed to different environments, for which I'm using workspaces.
Most of the components in the deployment should be created separately for each workspace, but I have several key components that I wish to be shared between them, primarily:
IAM roles and permissions
They should use the same API Gateway, but each workspace should deploy to different paths and methods
For example:
resource "aws_iam_role" "lambda_iam_role" {
name = "LambdaGeneralRole"
policy = <...>
}
resource "aws_lambda_function" "my_lambda" {
function_name = "lambda-${terraform.workspace}"
role = "${aws_iam_role.lambda_iam_role.arn}"
}
The first resource is a IAM role that should be shared across all instances of that Lambda, and shouldn't be recreated more than once.
The second resource is a Lambda function whose name depends on the current workspace, so each workspace will deploy and keep track of the state of a different Lambda.
How can I share resources, and their state, between different Terraform workspaces?
For the shared resources, I create them in a separate template and then refer to them using terraform_remote_state in the template where I need information about them.
What follows is how I implement this, there are probably other ways to implement it. YMMV
In the shared services template (where you would put your IAM role) I use Terraform backend to store the output data for the shared services template in Consul. You also need to output any information you want to use in other templates.
shared_services template
terraform {
backend "consul" {
address = "consul.aa.example.com:8500"
path = "terraform/shared_services"
}
}
resource "aws_iam_role" "lambda_iam_role" {
name = "LambdaGeneralRole"
policy = <...>
}
output "lambda_iam_role_arn" {
value = "${aws_iam_role.lambda_iam_role.arn}"
}
A "backend" in Terraform determines how state is loaded and how an operation such as apply is executed. This abstraction enables non-local file state storage, remote execution, etc.
In the individual template you invoke the backend as a data source using terraform_remote_state and can use the data in that template.
terraform_remote_state:
Retrieves state meta data from a remote backend
individual template
data "terraform_remote_state" "shared_services" {
backend = "consul"
config {
address = "consul.aa.example.com:8500"
path = "terraform/shared_services"
}
}
# This is where you use the terraform_remote_state data source
resource "aws_lambda_function" "my_lambda" {
function_name = "lambda-${terraform.workspace}"
role = "${data.terraform_remote_state.shared_services.lambda_iam_role_arn}"
}
References:
https://www.terraform.io/docs/state/remote.html
https://www.terraform.io/docs/backends/
https://www.terraform.io/docs/providers/terraform/d/remote_state.html
Resources like aws_iam_role having a name attribute will not create a new instance if the name value matches an already provisioned resource.
So, the following will create a single aws_iam_role named LambdaGeneralRole.
resource "aws_iam_role" "lambda_iam_role" {
name = "LambdaGeneralRole"
policy = <...>
}
...
resource "aws_iam_role" "lambda_iam_role_reuse_existing_if_name_is_LambdaGeneralRole" {
name = "LambdaGeneralRole"
policy = <...>
}
Similarly, the aws provider will effectively creat one S3 bucket name my-store given the following:
resource "aws_s3_bucket" "store-1" {
bucket = "my-store"
acl = "public-read"
force_destroy = true
}
...
resource "aws_s3_bucket" "store-2" {
bucket = "my-store"
acl = "public-read"
force_destroy = true
}
This behaviour holds even if the resources were defined different workspaces with their respective separate Terraform state.
To get the best of this approach, define the shared resources as separate configuration. That way, you don't risk destroying a shared resource after running terraform destroy.
I've been looking for a way to be able to deploy to multiple AWS accounts simultaneously in Terraform and coming up dry. AWS has the concept of doing this with Stacks but I'm not sure if there is a way to do this in Terraform? If so what would be some solutions?
You can read more about the Cloudformation solution here.
You can define multiple provider aliases which can be used to run actions in different regions or even different AWS accounts.
So to perform some actions in your default region (or be prompted for it if not defined in environment variables or ~/.aws/config) and also in US East 1 you'd have something like this:
provider "aws" {
# ...
}
# Cloudfront ACM certs must exist in US-East-1
provider "aws" {
alias = "cloudfront-acm-certs"
region = "us-east-1"
}
You'd then refer to them like so:
data "aws_acm_certificate" "ssl_certificate" {
provider = aws.cloudfront-acm-certs
...
}
resource "aws_cloudfront_distribution" "cloudfront" {
...
viewer_certificate {
acm_certificate_arn = data.aws_acm_certificate.ssl_certificate.arn
...
}
}
So if you want to do things across multiple accounts at the same time then you could assume a role in the other account with something like this:
provider "aws" {
# ...
}
# Assume a role in the DNS account so we can add records in the zone that lives there
provider "aws" {
alias = "dns"
assume_role {
role_arn = "arn:aws:iam::ACCOUNT_ID:role/ROLE_NAME"
session_name = "SESSION_NAME"
external_id = "EXTERNAL_ID"
}
}
And refer to it like so:
data "aws_route53_zone" "selected" {
provider = aws.dns
name = "test.com."
}
resource "aws_route53_record" "www" {
provider = aws.dns
zone_id = data.aws_route53_zone.selected.zone_id
name = "www.${data.aws_route53_zone.selected.name"
...
}
Alternatively you can provide credentials for different AWS accounts in a number of other ways such as hardcoding them in the provider or using different Terraform variables, AWS SDK specific environment variables or by using a configured profile.
I would recommend also combining your solution with Terraform workspaces:
Named workspaces allow conveniently switching between multiple
instances of a single configuration within its single backend. They
are convenient in a number of situations, but cannot solve all
problems.
A common use for multiple workspaces is to create a parallel, distinct
copy of a set of infrastructure in order to test a set of changes
before modifying the main production infrastructure. For example, a
developer working on a complex set of infrastructure changes might
create a new temporary workspace in order to freely experiment with
changes without affecting the default workspace.
Non-default workspaces are often related to feature branches in
version control. The default workspace might correspond to the
"master" or "trunk" branch, which describes the intended state of
production infrastructure. When a feature branch is created to develop
a change, the developer of that feature might create a corresponding
workspace and deploy into it a temporary "copy" of the main
infrastructure so that changes can be tested without affecting the
production infrastructure. Once the change is merged and deployed to
the default workspace, the test infrastructure can be destroyed and
the temporary workspace deleted.
AWS S3 is in the list of the supported backends.
It is very easy to use (similar to working with git branches) and combine it with the selected AWS account.
terraform workspace list
dev
* prod
staging
A few references regarding configuring the AWS provider to work with multiple account:
https://terragrunt.gruntwork.io/docs/features/work-with-multiple-aws-accounts/
https://assets.ctfassets.net/hqu2g0tau160/5Od5r9RbuEYueaeeycUIcK/b5a355e684de0a842d6a3a483a7dc7d3/devopscon-V2.1.pdf