run terraform in parallel across dependent workspaces

Terrallel is used to trace dependencies in an operator defined Infrafile of terraform workspaces. Terrallel will run any terraform command you supply in every workspace under a defined target with maximum parallelism. Terrallel is primarily designed for rapid creation and destruction of environments used for testing.

First, you define a YAML manifest describing workspaces. There are four possible keys.

targets: top level key. define named logical workspaces within.

Within targets, the following keys are allowed:

workspaces: list of paths to workspaces that do not depend on eachother.

group: list of target names that do not depend on eachother.

next: nest additional dependent group and workspaces entries under this.

There is one rule: workspaces and group cannot be sibling to eachother. If you require both in a target, they must be separated by a next key to nest them. This design decision enforces a configuration format where the order of operation is explicit. If workspace and group were allowed at the same level of nesting, terrallel would have to make an implicit assumption about which takes precedence to properly produce the dependency graph.

Here is a sample Infrafile from the examples directory. Examine that for more context.

terrallel:
  # This is a path relative to the Infrafile where all terraform workspaces
  # are located.
  basedir: environments
  # Targets can be defined in multiple files and imported only from the main
  # manifest file (Infrafile). If the same target is defined in multiple files
  # terrallel will error, no merging logic is supported.
  import:
  - terrallel/*.yml

# Targets can be defined in the main Infrafile. 
targets:
  dev:
    group:
    - dev-aws-networks
    - dev-gcp-networks
    next:
      workspaces:
      - dev/multi-cloud/networks
      next:
        group:
        - dev-gcp-clusters
        - dev-aws-clusters
        next:
          workspaces:
          - dev/multi-cloud/clusters

terrallel dev -- init
terrallel dev --dry-run -- apply -auto-approve
terrallel dev -- apply -auto-approve
terrralel dev -- destroy -auto-approve