How To Deploy Azure Container Apps With GitLab CI/CD

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Do you want to learn how to set up a pipeline to deploy an azure container app with GitLab CI/CD? In this post, I will show you how to use the GitLab CI to build an image, store it in the GitLab Registry and then deploy it to Azure Container Apps.

For that, we will first look at some requirements, either what’s needed for the automation to work or things that are required by the different tools we are using. And then, we will build up the CI and the different jobs inside it.

Requirements

Now let’s first look at some general requirements. First of all, we need a repository in GitLab which contains a Dockerfile that builds to an Image. Preferably to some sort of web application so we can quickly check if it is running successfully (for an example and step-by-step instructions, check this post here). In addition to that, you also need an Azure Account.

One requirement created through azure container apps is that you should use versioning of your images. Azure Container Apps will not pull the image every time we update the app, only when it sees that the version number changed! Meaning if we only use latest the automatic deployment will only work once. Because of that, we will use semantic-release, a tool that automatically generates a semantic version number from your commit messages. You do not have to use semantic release. There is also the possibility to do it manually or in whatever way you want.

In the end, the technologies we will use are the GitLab Registry, semantic-release, and Azure. To use these three technologies, we have to give them the access rights they need. Therefore we need to create:

For Azure, you could also use your own Account credentials, but I would recommend using a service principal inside of CIs and similar mechanics.

Before going to the next section, please create the three access methods with the linked tutorials.

GitLab CI to deploy to Azure Container Apps

After discussing the requirements, let’s create the CI and everything needed for it. The basic idea of the pipeline is simple and consists of three steps:

  1. Get version number
  2. Build image and push it to the registry
  3. Deploy image to container apps

For the first step, we need to add a semantic-release configuration file with the name .releaserc in the root of our project. Its contents should look something like this:

{
  "branches": ["main"],
  "plugins": [
    "@semantic-release/commit-analyzer",
    "@semantic-release/release-notes-generator",
    ["@semantic-release/gitlab", {
      "gitlabUrl": "https://gitlab.com",
      "repositoryUrl": "<your-repository-url>"
    }]
  ],
  "tagFormat": "${version}"
}

To learn more about the different configuration options, check here.

Now that we are able to run semantic-release in our GitLab CI, we will first create the three needed jobs and then add the environment variables:

stages:
  - release
  - build
  - deploy

# automatically retrieve version of the repository and create a new tag with repository settings this should occur on a merge
# semantic-release automates the whole package release workflow including: determining the next version number, generating the release notes, and publishing the package.
# It is required to set the GL_TOKEN environment variable
release:
  image: node:16-buster-slim
  stage: release
  before_script:
    - apt-get update && apt-get install -y --no-install-recommends git-core ca-certificates
    - npm install -g semantic-release @semantic-release/gitlab
  script:
    - semantic-release
  only:
    - main

# automatically build the docker image after the new tag is created
build:
  image: docker:latest
  stage: build
  only:
    - tags
  services:
    - docker:dind
  before_script:
    - docker login -u "$CI_REGISTRY_USER" -p "$CI_REGISTRY_PASSWORD" $CI_REGISTRY
  script:
    # get the version tag
    - tag=$CI_COMMIT_REF_NAME
    - docker build --pull -t "$CI_REGISTRY_IMAGE:${tag}" .
    - docker push "$CI_REGISTRY_IMAGE:${tag}"

# after the image build is finished use it for the containerapps and automatically deploy it
# container apps quickstart: https://docs.microsoft.com/de-de/azure/container-apps/get-started?tabs=bash
deploy:
  image: mcr.microsoft.com/azure-cli
  stage: deploy
  before_script:
    - az login --service-principal -u $AZURE_APP_ID -p $AZURE_PASSWORD --tenant $AZURE_TENANT
    - az extension add --name containerapp --upgrade
  script:
    - tag=$CI_COMMIT_REF_NAME
    # az containerapp up documentation: https://docs.microsoft.com/en-us/cli/azure/containerapp?view=azure-cli-latest#az-containerapp-up
    - az containerapp up --name $CONTAINER_APP_NAME --resource-group $RESOURCE_GROUP --location $LOCATION --environment $APP_ENV
      --registry-password $CI_REGISTRY_PASSWORD --registry-server $CI_REGISTRY --registry-username $CI_REGISTRY_USER
      --target-port $TARGET_PORT --ingress external
      --image "$CI_REGISTRY_IMAGE:${tag}"

    - az containerapp secret set --name $CONTAINER_APP_NAME --resource-group $RESOURCE_GROUP
      --secrets
      secret-key=$SECRET_KEY

    - az containerapp update --name $CONTAINER_APP_NAME --resource-group $RESOURCE_GROUP
      # --command <your-start-command>
      --cpu 1 --memory 2Gi
      --min-replicas 1 --max-replicas 10
      # --set-env-vars
      # SECRET_KEY=secretref:secret-key
      # ENV_VAR=$ENV_VAR
  only:
    - tags

As an explanation for the different jobs:

In the deployment, we have a three-step process because we first need to ensure a running app (up). Then we can add the secrets to the container app, and then we can update the other configurations. Especially the environment variables need the secrets to be set first. Otherwise, they can not be used.
To learn about all the configurations you can set with the last command, check here.

Now before we can run the pipeline, we need to set the following GitLab Variables:

With that, the CI/CD Variables should be specified, and you should be able to deploy your GitLab repository to azure container apps on a commit to the main branch.

Conclusion

In this post, you learned how to create a GitLab pipeline to automatically deploy an application to Azure Containerapps! I hope that it helped you, and in case there are any questions, feel free to leave a comment or send me an email at mail@programonaut.com.

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