#atmos (2023-09)

situation of setting up different similar infra eg. different buckets, couple queues. If you have a lot of queues or buckets seems odd/cumbersome to have to deploy every queue separate

that depends on how you structure your Terraform components. One component can provision one thing, or a set of similar things

how you structure the components, depends on a few considerations:

1. lifecycle management - if all of those resources have the same lifecycle, they can probably be deployed together as a set (e.g. ECR repos). On the other hand, if you have many different buckets, and they are not related to each other, they should be provisioned as separate components.

1. How big you want your Terraform state be - the smaller the component, the smaller is Terraform state. The more resources you provision in one apply, the longer it takes, to the point that it can become unmanageable

1. Blast radius - if all components of the same type are provisioned together in one terraform apply, if something goes wrong, all of them break. This is especially important in, for example, networking layer, b/c if you screw up your VPC/subnets/routes, then the entire account goes down. That’s why VPCs and subnets are usually provisioned separately and not all of them in one terraform apply

2. If similar components are provisioned in different account and regions, then they should be provisioned separately. Otherwise, you’ll have to define a bunch of providers in the component, each provider for a specific account and region, instead of just setting a few variables (like stage , environmnet and region in case of CloudPosse components). For example, vpc-flow-log-bucket for VPCs in different accounts and regions. Any databases in diff accounts and regions, etc.

3. What people/teams are responsible for the resources. If different teams are managing the same type of resources, eg s3 buckets for logs and s3 buckets for analytics, the resources must be provisioned as separate components with separate access control

if not considering all of that, you could put all your resources into one huge component named “infra”, and provision everything in one terraform apply, which is obviously not a good idea

Allright thanks, thats helpful

Also a good question for #office-hours

if you are using cloudposse components and null label then is not that easy because the resources are named after the merge of the null-label variables so it will trigger a recreate

you could do a lot of moved {} blocks in tf to maybe accomodate this but it will still be tricky

https://github.com/cloudposse/terraform-spacelift-cloud-infrastructure-automation/blob/main/modules/spacelift-policy/variables.tf

currently, you can specify a policy inline, or using a URL

variable "body" {
  type        = string
  description = "The body of the policy to create. Mutually exclusive with `var.body_url`."
  default     = null
}

variable "body_url" {
  type        = string
  description = "The URL of file containing the body of policy to create. Mutually exclusive with `var.body`."
  default     = null
}

local files are not supported by the module, so you can:

1. Open a PR and add that support
2. Write you own component that wraps the spaceift-policy module and use the file Terraform function to read a policy from a file and use the body variable

Thank you for confirming its use.

Have you looked into Workflows?

Keep in mind we built atmos to be generic in that sense, so it’s not aware really of anything terraform does

In our reference architecture we rely on workflows to automate the process of bringing up and tearing down layers. A layer is a collection of stacks.

Thanks Erik, workflows haven’t been utilized when this project was conceived

I’ll try with one

did you try https://atmos.tools/category/quick-start ?

also, if you have any questions on how to start, ask, will be able to help

+1 for running through the quick start. I was able to get an initial base structure going last night using digital ocean. Will be getting my examples in a public repo soon to share/take feedback

Here is my current layout:

|-- atmos.yaml
|-- components
|   |-- ansible
|   |   |-- inventory
|   |   `-- playbook.yaml
|   `-- terraform
|       `-- vpc
|           |-- main.tf
|           |-- providers.tf
`-- stacks
    |-- catalog
    |   `-- terraform
    |       `-- vpc.yaml
    |-- mixins
    |   `-- region
    |       |-- globals.yaml
    |       `-- nyc3.yaml
    `-- nyc3
        `-- mystack.yaml

mystack.yaml imports

import:
  - mixins/region/globals
  - mixins/region/nyc3
  - catalog/terraform/vpc

Right now I’m just running ansible-playbook -i components/ansible/inventory components/ansible/playbook.yaml after atmos applies terraform.

@Andriy Knysh (Cloud Posse)

Atmos is concerned about configuration for components, it does not know anything how to work with different external tools (it know about Terraform, but that’s a special case). So you have a few choices, all of them require creating a terraform component or a shell script (which can definitely be used in an Atmos custom command)

1. In the component, use https://developer.hashicorp.com/terraform/language/resources/provisioners/remote-exec to execute ansible configuration code on the remote machine

1. Use https://developer.hashicorp.com/terraform/language/resources/provisioners/local-exec to execute the ansible code on the local machine

1. Use the ansible TF provider https://registry.terraform.io/providers/ansible/ansible/latest/docs to define all ansible resources in Terraform (probably the best choice b/c all the Ansible config will be in the TF state)

1. Create a shell script and use it from a custom Atmos command

Once you have the new TF code (using #1, #2, or #3), you can use Atmos to configure the variables and other settings for the component, and then provision it using atmos terraform apply

@Chris Bloemker

all of the troubles above is only when you don’t want to run ansible-playbook -i components/ansible/inventory components/ansible/playbook.yaml after you apply terraform, meaning you don’t want to run two commands instead of one

Thanks Andriy. I have worked with the provisioner before but it’s been some time, I like the idea of the ansible tf provider. I think grouping the ansible configuration into the same logical component makes sense (having the component provision the droplet instance as well as configure the app as one piece). I’m locally applying right now but want to move into s3 backend state and have GitHub actions running the atmos commands and maybe even move into Atlantis.

you can generate all or some of your TF vars files and your backend files

but you need to select the stack and or component

after that you just run init/plan/apply with pure TF

look at this : https://atmos.tools/integrations/atlantis#example-github-action

the github action atmos commands

I used that to generate all the files so that Atlantis can run just pure TF

I think OP wants to generate these files.

(this command does not exist and only for this example)

atmos create component xyz

and have these files automatically created

components/terraform/xyz/main.tf
components/terraform/xyz/outputs.tf
components/terraform/xyz/variables.tf
components/terraform/xyz/providers.tf
components/terraform/xyz/README.md
stacks/catalog/xyz.yaml

is that right @shmileee?

(we want to implement a scaffolding command like that, but we do not currently have one)

Techncially vendoring can be used. Just vendor a scaffolding repo.

cc @Andriy Knysh (Cloud Posse)

ahhhh I c

@shmileee if you want to generate these files

components/terraform/xyz/main.tf
components/terraform/xyz/outputs.tf
components/terraform/xyz/variables.tf
components/terraform/xyz/providers.tf
components/terraform/xyz/README.md

then we don’t support it currently

and in any case, we would be able generate only empty files (which is not very useful)

b/c to generate something useful, we would need to have that information somewhere

that information can be, as it currently supported, in component.yaml file. You can create a folder components/terraform/<my-component> and place component.yaml file in there

then use Atmos vendoring to download the code for the component from our open source catalog https://github.com/cloudposse/terraform-aws-components, or any other location (your catalog, public repos, etc.)

https://atmos.tools/core-concepts/components/vendoring

So, if my understanding is correct, then I want to generate the *.tf files and backend for the stack, rather than component. Cause stack is higher level than component, right? I guess it’s not possible.

Offtopic: hey fellow mates from Atlantis project, just asked you the question about atmost + atlantis earlier today

( I answered that question in the Atlantis Slack, same guy here )

you will be able to generate the backend.tf for that component but as @Andriy Knysh (Cloud Posse) said you will not be able to generate the TF files to build the component skeleton/template , that is why he is suggesting to have am external repo where you have your baseline/skeleton/template backend component structure and use atmos vendor command to pull that structure when you are working on a new component

having said that, we can def implement something like atmos generate terraform component <name> and create empty terraform files in components/terraform/<name> folder and add some initial stack configs in stacks/catalog/<name>/defaults.yaml (w/o specifying values for any variables b/c we don’t have that information)