Overview

This project provides a complete solution for creating and deploying a self-hosted agent/runner for Azure DevOps and Github using Docker containers. The solution supports automated deployment using bicep to Azure cloud where the agent/runner is hosted. The Docker container provides high portability and the ability to easily move agents across different environments.

• Agent Docker Container
• Introduction
• Azure DevOps Pipelines
• Github Actions
• Virtual Network
• Contributing
• License

Agent Docker Container

ADO Pipelines Agent Linux Container

Read src/images/ado-agent-linux/README.md for more.

Github Actions Runner Linux Container

Read src/images/github-runner-linux/README.md for more.

Introduction

Build

The first step to create a hosted agent is to build the docker image which contains the agent and all the required tools, then push the image to Azure Container Registry (ACR).

Release

The second step is to create an Azure Container Instance (ACI) and use the agent Docker image created in the previous step. The necessary environment variables should be passed to the container instance. This will create and run a container that hosts the agent.

Note Multi-container groups currently support only Linux containers. For Windows containers, Azure Container Instances only supports deployment of a single container instance. See more

flowchart LR
    subgraph build [Build]
    direction TB
    A(Agent/Runner Docker Container) -->|Build pipeline/workflow| B(Build & Publish Container Image)
    B -->|Push agent/runner image | C(Azure Container Registry)
    end
    build-->release
    subgraph release [Release]
    direction TB
    K(Azure Container Registry)-->|Release pipeline/workflow| L(Azure Container Instance)
    L-->|Register| P(Agent / Runner)
    L -->|Register| Q(Agent / Runner)
    end

Loading

Azure DevOps Pipelines

Pre-requisites

Service Connection

To deploy azure resources you need an Azure Resource Manager service connection.

You need to have the right permission to be able to create a service connection.

• In Azure DevOps, open the Service connections page from the project settings page.
• Click Create service connection and select Azure Resource Manager then click Next.
• Select Service principal (automatic), then click Next.
• Specify Scope level, Subscription, Resource group and Service connection name then click Save.

Agent pool

An agent pool is a collection of agents. When the pipeline runs, it runs on one of the agents from the specified agent pool.

To create a new agent pool:

• In Azure DevOps, open the Agent pools page from the project settings page.
• Click Add pool.
• Select New pool to link.
• Select Self-hosted from the pool type menu.
• Specify name, then click Create.

Personal Access Token (PAT)

A personal access token (PAT) contains your security credentials for Azure DevOps. It will be used by the self-hosted agent to authenticate into Azure DevOps.

To create a new PAT:

• From your home page, open user settings and select Personal access tokens.
• Select + New Token.
• Specify a name, select the organization where you want to use the token, and then set the expiration.
• Select the following scopes:
  • Agent Pools (Read & manage)
  • Deployment Groups (Read & manage)
• Copy the token and store it in a secure location as it won't be shown again.

Configure pipelines

Create Build pipeline

Create build pipeline using an exisitng yaml file and select .azuredevops/pipelines/build.yml file.

Required Environment Variables

• ENV_AZURE_CONNECTION The name of the azure service connection
• ENV_AZURE_RG The name of the resource group.
• ENV_ACR_NAME The name of the azure container registry.

Create Deploy pipeline

Create build pipeline using an exisitng yaml file and select .azuredevops/pipelines/release.yml file.

Required Environment Variables

• ENV_AZURE_CONNECTION The name of the azure service connection
• ENV_AZURE_RG The name of the resource group.
• ENV_ACR_NAME The name of the azure container registry.
• ENV_AZP_LNX_POOL The name of the Azure DevOps agent pool to deploy the linux self-hosted agents to.
• ENV_AZP_WIN_POOL The name of the Azure DevOps agent pool to deploy the windows self-hosted agents to.
• ENV_AZP_PAT Azure DevOps personal access token with the right permissions to allow the self-hosted agent to connect to Azure DevOps.
• ENV_LNX_ACI_NAME The name of the Azure Container Instance to deploy the linux self-hosted agent image to.
• ENV_WIN_ACI_NAME The name of the Azure Container Instance to deploy the windows self-hosted agent image to.
• ENV_SUBNET_ID The subnet resource Id for the container instance.
• ENV_DNS_SERVERS A string array of private DNS servers to use. ACI does not inherit DNS from your virtual network. Example argument format - ["192.168.1.1", "192.168.1.2"]. Supply empty array [] to use default Azure resolver.

Run Build pipeline

Run the build pipeline and when it is completed go to Azure portal and verify that the ACR is created and the agent image is published.

Run Release pipeline

Run the deploy pipeline and when it is completed go to the agent pool and verify that the agents are created and online.

Github Actions

Pre-requisites

Azure Service Principal

To deploy azure resources you need a service principal with sufficient permissions on the target Azure Subscription or Resource Group. Then, generate a secret and be sure to copy the token and store it in a secure location, as it cannot be viewed again later.

Personal Access Token (PAT)

A personal access token (PAT) contains your security credentials for Github. It will be used by the self-hosted runner to call Github API to generate a self-hosted runner's registration token.

To create a new PAT:

• Log in to your GitHub account.
• In the top-right corner of the screen, click on your profile photo and select "Settings".
• In the left sidebar, select "Developer settings".
• Click on "Personal access tokens" then select "Fine-grained tokens".
• Click the "Generate new token" button.
• Give your token a descriptive name to help you remember its purpose.
• Select the desired permissions for the token:
  • Read and Write next to "Administration".
• Click the "Generate token" button at the bottom of the page.

Your new token will appear on the screen. Be sure to copy the token and store it in a secure location, as it cannot be viewed again later.

Secrets and variables

The following secrets and variables are required by the Github actions workflows:

Secrets

• ENV_AZURE_CREDENTIALS Azure credentials to authenticate with Azure. Paste the following JSON into the secret's value field:

{
    "clientId": "<sp_client_id>",
    "clientSecret": "<sp_client_secret>",
    "subscriptionId": "<azure_subscription_id>",
    "tenantId": "<azure_tenant_id>"
}

Replace <azure_subscription_id> with the subscription ID, <azure_tenant_id> with the tenant ID, <sp_client_id> and <sp_client_secret> with the service principal Client ID and Client Secret generated from the previous step.

• ENV_GITHUB_TOKEN: Github personal access token generated from the previous step.

Variables

• ENV_AZURE_RG The name of the resource group.
• ENV_ACR_NAME The name of the azure container registry.
• ENV_LNX_ACI_NAME The name of the Azure Container Instance to deploy the linux self-hosted runner image to.
• ENV_WIN_ACI_NAME The name of the Azure Container Instance to deploy the windows self-hosted runner image to.
• ENV_SUBNET_ID The subnet resource Id for the container instance.
• ENV_DNS_SERVERS A string array of private DNS servers to use. ACI does not inherit DNS from your virtual network. Example argument format - ["192.168.1.1", "192.168.1.2"]. Supply empty array [] to use default Azure resolver.

Run Build workflow

Run the "Build Actions Runner" workflow and when it is completed go to Azure portal and verify that the ACR is created and the agent image is published.

Run Release workflow

Run the "Deploy Actions Runner workflow" and when it is completed go to the repository settings then Actions then Runners and verify that the runners are created.

Virtual Network

Running self-hosted agents/runners inside a VNet allows pipelines jobs to access private resources inside the VNet. This can be particularly useful when deploying applications that require access to private databases, file shares, or other resources that are only accessible from within the VNet. By running the agents/runners inside the VNet, you can ensure that the pipeline jobs have access to these resources without exposing them to the public internet.

To allow running Azure Container Instances (ACI) inside a VNet, you need to create a subnet specifically for the ACI. The subnet must be delegated to Azure Container Instances, which allows Azure to manage the underlying infrastructure for the ACI. To delegate the subnet, you need to configure the subnet properties to enable the "Microsoft.ContainerInstance/containerGroups" delegation. Once the delegation is enabled, you can pass the ACI subnet resource id to the src/infrastructure/aci/main.bicep subnetResourceId parameter and run the release pipeline/workflow.

Note Once an Azure Container Instance (ACI) is deployed into a subnet, you cannot change the subnet associated with it. This means that if you need to move an ACI to a different subnet, you will need to delete and redeploy the ACI in the new subnet.

Contributing

If you'd like to contribute to this repository, please create a pull request with your proposed changes. Be sure to include a detailed description of what your changes accomplish and any testing you've done to ensure the scripts continue to work as expected.

License

This code is licensed under the MIT license. Please see the LICENSE file for more information.