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Final Notes

Atmos provides unlimited flexibility in defining and configuring Atmos stacks and Atmos components in the stacks.

  • Terraform components can be in different sub-folders in the components/terraform directory. The sub-folders can be organized by type, by teams that are responsible for the components, by operations that are performed on the components, or by any other category

  • Atmos stacks can have arbitrary names and can be located in any sub-folder in the stacks directory. Atmos stack filesystem layout is for people to better organize the stacks and make the configurations DRY. Atmos (the CLI) does not care about the filesystem layout, all it cares about is how to find the stack and the component in the stack by using the context variables namespace, tenant, environment and stage

  • An Atmos component can have any name different from the Terraform component name. For example, two different Atmos components vpc-1 and vpc-2 can provide configuration for the same Terraform component infra/vpc

  • We can provision more than one instance of the same Terraform component (with the same or different settings) into the same environment by defining many Atmos components that provide configuration for the Terraform component. For example, the following config shows how to define two Atmos components, vpc-1 and vpc-2, which both point to the same Terraform component infra/vpc:

    import:
      - mixins/region/us-east-2
      - orgs/acme/core/dev/_defaults
      - catalog/vpc

    components:
      terraform:

        vpc-1:
          metadata:
            component: infra/vpc
            inherits:
              - vpc/defaults
          vars:
            name: vpc-1
            ipv4_primary_cidr_block: 10.9.0.0/18

        vpc-2:
          metadata:
            component: infra/vpc
            inherits:
              - vpc/defaults
          vars:
            name: vpc-2
            ipv4_primary_cidr_block: 10.10.0.0/18

    Then we can execute the following atmos commands to provision the two VPCs into the dev account in the us-east-2 region:

    atmos terraform apply vpc-1 -s core-ue2-dev
    atmos terraform apply vpc-2 -s core-ue2-dev

All the above makes Atmos an ideal framework to organize infrastructure, to design for organizational complexity, and to provision multi-account environments for very complex organizations.