Github action jobs are skipped randomly

Question

I have the following workflow:

name: Test Job

on:
  workflow_dispatch:
  schedule:
    - cron: "30 2 * * *"

jobs:
  job1:
    uses: ./.github/workflows/job1.yml
    with:
      var: true
    secrets: inherit

  job2:
    uses: ./.github/workflows/job2.yml
    secrets: inherit

  job3:
    uses: ./.github/workflows/job3.yml
    with:
      var2: false
    secrets: inherit

  job4:
    uses: ./.github/workflows/job4.yml
    with:
      var3: latest
    secrets: inherit
   

If I run this via a worflow_dispact, 2 of the jobs will be executed (in parallel) and the other two would be skipped.

It appears to be random which ones run and which ones are skipped. For example, one run, 1&4 ran, 2&3 were skipped. Next run 1, 2, and 4 ran, 3 was skipped.

The ones that run pass. I ran 1 & 2 together (3 & 4 commented out), then 3 & 4 together ( 1 & 2 commented out) and both of those runs were successful.

I thought the other 2 might be timing out, but they actually get skipped within of minute of kicking off the run.

EDIT: Just noticed that jobs 1,2, and 3 all have the following:

concurrency:
  group: ci-tests-${{ github.ref }}-1
  cancel-in-progress: true

Any ideas what might be causing this?

Answer 1

The concurrency controls you amended in your edit are responsible; they all use the same value for group, resulting in jobs 1, 2, and 3 cancelling each other, with only the most recent job "surviving".

To fix, make sure group has a value unique to the jobs that are supposed to cancel each other, e.g., by replacing -1 with -2 and -3 in the corresponding reusable workflows.