GH-200 GitHub Actions Exam Questions and Answers

While Docker can run on various operating systems, Linux is often the most common and preferred OS for containerized workloads. Docker works well on Linux and is a widely-used platform for running containers.

For container jobs to run on a self-hosted runner, Docker must be installed and properly configured on the runner. Docker is required to build and run containerized workloads in a GitHub Actions workflow.

The matrix configuration specifies two variables: color and animal. The color variable has 2 values (green and pink), and the animal variable has 2 values (owl and magpie). This would result in 4 combinations (2 color values × 2 animal values). Additionally, the include section introduces two more combinations (color: blue and animal: owl; color: pink and animal: magpie).

GitHub secrets are defined at different levels: organization, repository, and sometimes at the workflow level. If a secret is defined at both the organization level and the repository level, the repository-level secret will take precedence. So, if the value of the secret differs between these levels, the workflow will use the value from the repository level instead of the organization level.

The $GITHUB_ENV environment variable is used to set environment variables that persist across steps in a workflow job. By echoing FOO=bar into $GITHUB_ENV, the variable FOO will be available in subsequent steps within the same job.

Creating a separate repository for each custom action allows you to manage the versioning independently for each action. This approach provides flexibility, as each action can be updated, tested, and versioned separately, avoiding potential conflicts or dependencies between different actions.

A. Use the actions/setup-docker action

B. Authenticate to the GitHub Container Registry.

C. Build the container image.

D. Push the image to the GitHub Container Registry

E. Pull the image from the GitHub Container Registry.

The workflow_call event is used to trigger a reusable workflow from another workflow. This allows you to create workflows that can be reused in multiple places within your organization, enabling better modularity and reducing duplication.

GitHub-hosted runners have a limit on the number of concurrent workflows (typically 20 for free-tier accounts and 5 for enterprise). If your organization needs to run more workflows simultaneously, you would need to use self-hosted runners to increase the available concurrency.

Self-hosted runners allow you to configure specialized hardware or software setups that are necessary for certain workflows. GitHub-hosted runners may not have access to custom hardware configurations like GPUs or other specialized resources, so self-hosted runners are required in such cases.

Workflow commands are special commands that allow you to interact with the runner, set environment variables, output values, add debug messages, and perform other tasks within the workflow. These commands are used to modify the environment or influence the behavior of the GitHub Actions runner.

The needs context is used to reference the outputs of jobs that are dependencies of the current job. In this case, needs.job1.outputs.output1 correctly accesses the output of output1 from the job job1 in the dependent job.

The provided event trigger block specifies two types of events:

For issues: the workflow triggers on opened or edited issues.

For issue_comment: the workflow triggers when an issue comment is created.

This configuration ensures the workflow will run when either an issue is opened or edited, or an issue comment is created.

Creating workflow templates in the organization’s .github repository allows the organization to standardize workflows and make them easily reusable across multiple repositories. This ensures consistency and simplifies maintenance.

Creating reusable actions and workflows that can be called from other workflows helps modularize and standardize automation tasks. These reusable components can be maintained centrally and called from different workflows across repositories.

You can enable specific actions for the organization by identifying them and providing version control, ensuring only trusted versions are used in workflows.

GitHub-verified actions can be enabled at the enterprise level, providing an extra layer of security by ensuring that only trusted actions are available to workflows.

Actions can be published to an internal marketplace, allowing organizations to share reusable actions securely within their enterprise without exposing them to the public.

The action.yml file is the metadata file in a custom GitHub Action that defines the main entry point, including information such as the inputs, outputs, description, and the runs key that specifies the main entry point (e.g., a script or a Docker container).

When troubleshooting a self-hosted runner, you can access the _diag folder located in the self-hosted runner's installation directory. This folder contains diagnostic logs that can help you identify the root cause of issues, such as connection problems.

The GITHUB_TOKEN is automatically provided by GitHub in workflows and can be used to authenticate API requests to GitHub, including publishing packages to GitHub Packages.

The GITHUB_TOKEN is also used to authenticate API requests for actions like creating issues, commenting, or interacting with pull requests within the same repository.

Using a corporate secret store like HashiCorp Vault provides a secure, centralized location for sensitive information. GitHub Actions can then retrieve and store the token securely during deployment by setting it as an environment variable, ensuring the token remains secure and accessible at runtime.

Storing the token as an organizational-level encrypted secret in GitHub ensures it is accessible across multiple repositories, minimizing management overhead. GitHub Actions can then use this secret during deployment by setting it as an environment variable, allowing the microservice to access it securely at runtime.

Actions can be stored in a separate public repository and referenced in workflows by specifying the repository and action name.

Actions can also be stored in the same repository as the workflow and referenced directly by their path (e.g., ./.github/actions/my-action).

Actions can be packaged as Docker container images and published to Docker Hub. These can then be referenced in workflows by specifying the Docker image.