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docker-kubernetes-client

This is a small image that allows to run git, docker, kubectl and helm.

It also provides some convenient commands to perform a release.

Usage

Perform the deployment from .gitlab-ci.yml:

image: edoburu/gitlab-kubernetes-client

stages:
- build
- deploy

before_script:
  # Allow sh substitution to support both tags and commit releases.
  # CI_PIPELINE_ID is useful to force redeploys on pipeline triggers
  # CI_COMMIT_TAG is only filled for tags.
  # CI_COMMIT_REF_NAME can be a tag or branch name
  - export IMAGE_TAG=ci_${CI_PIPELINE_ID}_${CI_COMMIT_TAG:-git_${CI_COMMIT_REF_NAME}_$CI_COMMIT_SHA}

build image:
  stage: build
  script:
  - docker build -t $CI_REGISTRY_IMAGE:$IMAGE_TAG .
  - docker run --rm $CI_REGISTRY_IMAGE:$IMAGE_TAG /script/to/run/tests
  - docker login -u $CI_REGISTRY_USER -p $CI_JOB_TOKEN $CI_REGISTRY
  - docker push $CI_REGISTRY_IMAGE:$IMAGE_TAG

deploy to production:
  stage: deploy
  environment:
    name: production
    url: http://example.com/
  when: manual
  script:
  - helm upgrade
        --install
        --tiller-namespace="$KUBE_NAMESPACE"
        --namespace "$KUBE_NAMESPACE"
        --reset-values
        --values "values-$CI_ENVIRONMENT_SLUG.yml"
        --set="image.tag=$IMAGE_TAG,nameOverride=$CI_ENVIRONMENT_SLUG"
        "RELEASE_NAME" "CHART_DIR"
  only:
  - tags
  - triggers
  except:
  - beta  # when part of trigger

Instead of running helm directly, you can also use the more friendly create-release script:

create-release "RELEASE_NAME" "CHART_DIR" --values "values-$CI_ENVIRONMENT_SLUG.yml" --set="image.tag=$CI_COMMIT_TAG"

Any helm arguments can be passed, including --dry-run --debug to see what would happen.

Notes

The examples assume you'll create a values-{env}.yml file with specific deployment configurations per environment.

Some extra settings might be needed to perform docker builds, this depends on your setup for building docker images in GitLab

The 'trigger' feature can be used to allow redeploys for an updated base image. This can be used to automatically deploy security updates.

Preparation

Provide a container registry

You can use any registry (e.g. cloud based like Docker Hub). In the examples, it's assumed that the GitLab container registry is enabled. This also provides several variables during build:

  • $CI_REGISTRY_IMAGE that points to your registry.example.com/namespace/project.
  • $CI_REGISTRY points to your registry.example.com
  • $CI_REGISTRY_USER points to a user account.
  • $CI_JOB_TOKEN is a rotating password that can be used to push images.

When the GitLab container registry is not enabled, provide these environment variables using secret build variables, so the example .gitlab-ci.yml still works without changes.

Create a namespace for the app

Preferably, different clients should exist in different namespaces. There is a helper script to do everything for you:

docker run --rm -v "$HOME/.kube:/root/.kube" edoburu/gitlab-kubernetes-client create-namespace MY_NAMESPACE

This installs Tiller in a single namespace, with a tiller and deploy user. At the end, it prints all settings needed for GitLab Kubernetes integration.

You can pass --dry-run to see the configuration it would apply.

Make sure Kubernetes can access your GitLab container registry

  1. Create a personal access token in your GitLab account settings and give it read_registry access.
  2. Store the access token as a docker-registry secret in Kubernetes:
kubectl create secret gitlab-registry $NAME \
    --namespace=$NAMESPACE \
    --docker-server=registry.example.com \
    --docker-username=USERNAME \
    --docker-email=EMAIL \
    --docker-password=PERSONAL_ACCESS_TOKEN
  1. Use this secret in the imagePullSecrets.

Either in the pod template:

kind: Deployment
spec:
  template:
    spec:
      imagePullSecrets:
        - name: gitlab-registry
      containers:
        - image: "{{ .Values.image.repository }}:{{ .Values.image.tag }}"

Or in the serviceaccount of the Pod.

Make sure GitLab can access Kubernetes

The create-namespace already gave all values for it, but you can request them again for the deploy user:

docker run --rm -v "$HOME/.kube:/root/.kube" edoburu/gitlab-kubernetes-client get-gitlab-settings deploy namespace=NAMESPACE

Open the GitLab Kubernetes integration in your project to enter the displayed values

When Kubernetes integration is enabled, GitLab adds several environment variables to the build environment so kubectl and helm Just Work (TM):

  • $KUBECONFIG points to a kubeconfig file
  • $KUBE_CA_PEM contains the full CA certificate data.
  • $KUBE_CA_PEM_FILE points to a file with the CA certificate data.
  • $KUBE_NAMESPACE points to your namespace
  • $KUBE_TOKEN contains your service account token
  • $KUBE_URL contains your API server URL.

Using standard helm charts

Helm is already initialized, so no helm init --client-only is needed. When you use charts from standard Kubernetes Chart repositories, download the latest repository caches:

helm repo update

Afterwards, helm install stable/... works as expected.