Docs/Guides

Move workflows to Anvil runners

CI → Run on Anvil reads a GitHub repository's workflows, shows exactly which lines change, and opens one pull request that switches them to an Anvil runner. Nothing runs differently until you merge it.

Open the pull request #

Open CI → Run on Anvil.
Pick the repository. Only GitHub repositories with the Anvil app are listed.
Pick a size: anvil-2cpu, anvil-4cpu or anvil-8cpu.
Untick any workflow you want to leave out.
Click Open pull request, and merge it on GitHub when its checks look right.

The preview: each workflow with the lines that change and the jobs that stay

The pull request comes from the Anvil app on a branch named anvil/runners-<id>. Its description lists every changed line.

What changes and what doesn't #

Anvil changes only the runs-on line of each job, and keeps your comments, quotes and indentation.

`runs-on` today	After
`ubuntu-latest`, `ubuntu-24.04`, `ubuntu-22.04`	`anvil-4cpu` (the size you picked)
`[ubuntu-latest]` or a one-item list	the same list with `anvil-4cpu`
`blacksmith-4vcpu-ubuntu-2404` and other Blacksmith Ubuntu labels	`anvil-4cpu`
`${{ matrix.os }}` with Ubuntu entries in the matrix	an expression that sends only the Ubuntu entries to Anvil (below)
Already `anvil`, `anvil-*`, or with `anvil-sticky`	left alone
`self-hosted`, several labels, a runner group	left alone
`macos-`, `windows-`, `*-arm`	left alone: Anvil runs Linux x64 jobs
Any other expression, such as `${{ inputs.runner }}`	left alone

Jobs that call a reusable workflow (uses:) have no runner of their own; change the called workflow instead.

Matrix jobs #

Matrix values often appear elsewhere (if: matrix.os == 'ubuntu-latest', cache keys, job names), so Anvil doesn't touch the matrix. It changes runs-on to pick Anvil for the Ubuntu entries only:

diff

   strategy:
     matrix:
       os: [ubuntu-latest, macos-latest]
-  runs-on: ${{ matrix.os }}
+  runs-on: ${{ matrix.os == 'ubuntu-latest' && 'anvil-4cpu' || matrix.os }}

The macOS entry keeps running on GitHub. A matrix built by an expression (fromJSON(...)) is left alone, because Anvil can't see its values.

Go back #

Change runs-on back, or revert the pull request. Nothing else in the workflow changed.

Do it by hand #

The same change works in any editor:

yaml

jobs:
  test:
    runs-on: anvil-4cpu

Sizes, caches and limits are in Runner sizes and labels.