how to run parallel jobs in github actions

GitHub Actions allows for parallel job execution to enhance workflow efficiency. By employing the "parallel" keyword, multiple jobs run concurrently, reducing task completion times. The article explores the maximum number of parallel jobs,

How to Run Parallel Jobs in GitHub Actions

GitHub Actions is a powerful tool for automating your software development workflow. One of the features that makes GitHub Actions so powerful is the ability to run parallel jobs. This can be a huge time-saver for tasks that can be broken down into smaller, independent steps.

To run parallel jobs in GitHub Actions, you need to use the parallel keyword in your workflow file. The parallel keyword takes a list of job names as its argument. For example, the following workflow file will run two jobs, job1 and job2, in parallel:

<code class="yaml">name: My Workflow

on: [push]

jobs:
  job1:
    runs-on: ubuntu-latest
    steps:
      - echo "Hello from job1!"

  job2:
    runs-on: ubuntu-latest
    steps:
      - echo "Hello from job2!"</code>

When this workflow is run, both job1 and job2 will start running at the same time. Once both jobs have completed successfully, the workflow will complete.

How Many Simultaneous Parallel Jobs Can Be Run in GitHub Actions?

The number of simultaneous parallel jobs that can be run in GitHub Actions depends on the type of runner that you are using. For self-hosted runners, the maximum number of parallel jobs that can be run is equal to the number of CPUs on the runner. For GitHub-hosted runners, the maximum number of parallel jobs that can be run is 20.

Can Parallel Jobs in GitHub Actions Share the Same Secrets?

Yes, parallel jobs in GitHub Actions can share the same secrets. To share secrets between parallel jobs, you can use the secrets context. The secrets context is a dictionary that contains all of the secrets that are available to the workflow.

To access the secrets context in a job, you can use the secrets keyword. For example, the following job will print the value of the MY_SECRET secret:

<code class="yaml">name: My Job

on: [push]

jobs:
  job1:
    runs-on: ubuntu-latest
    steps:
      - echo "The value of MY_SECRET is: ${{ secrets.MY_SECRET }}"</code>

How to Debug Parallel Jobs in GitHub Actions?

There are a few different ways to debug parallel jobs in GitHub Actions. One way is to use the actions/runner-debug action. This action will print a lot of useful information about the runner, including the environment variables that are available to jobs.

To use the actions/runner-debug action, add the following to your workflow file:

<code class="yaml">name: My Workflow

on: [push]

jobs:
  job1:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/runner-debug@v1</code>

Once you have added the actions/runner-debug action to your workflow file, you can run the workflow and see the output in the GitHub Actions logs.

Another way to debug parallel jobs in GitHub Actions is to use the -vv flag when running the github-actions CLI. This flag will print a lot of additional information about the workflow, including the steps that are being executed and the resources that are being used.

To use the -vv flag, run the following command:

<code>github-actions -vv run workflow.yaml</code>

The output of the -vv flag can be helpful for troubleshooting issues with parallel jobs.

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