Upgrading a Helm-deployed Concourse

Introduction

Helm is the package manager for Kubernetes, a tool that streamlines installing and managing Kubernetes applications. It creates Kubernetes objects that can be submitted to Kubernetes clusters, and materialized into a Concourse deployment using Kubernetes constructs (Deployments, StatefulSets, PersistentVolumeClaims, etc).

A Helm Chart is a versioned package of pre-configured Kubernetes resources. Deploying Concourse via Helm Chart makes it easy to deploy, scale, maintain, or upgrade your deployment in the future. This guide aims to walk an operator through the step by step process of deploying with Helm.

Once you've deployed Concourse to a Kubernetes cluster, you can use the following process to keep it up to date as new releases arrive on VMware Tanzu Network.

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Backup

In the case of a Helm-deployed Concourse pointed to a Postgres database that has been deployed and managed with BOSH, you can use BBR to perform a backup.

Otherwise, use the pg_dump utility to backup your Postgres database. For more information on the tool, click here to view a guide on postgresql.org.

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Download, Tag, and Push Images to Internal Registry

Download Concourse Helm Chart and load images into Docker

1. If you have not already done so, visit VMware Tanzu Network and download the Concourse Helm Chart.

2. Unarchive the Helm Chart tarball to a local directory. For example, with version v5.5.8, the tarball will be called concourse-5.5.8-helm.tgz.

   mkdir concourse-helm
   

   tar xvzf ./concourse-5.5.8-helm.tgz -C ./concourse-helm
   

   cd ./concourse-helm
   

3. Load the container images into a local Docker client by running the following docker load commands one at a time:

   docker load -i ./images/concourse.tar
   

   docker load -i ./images/postgres.tar
   

   docker load -i ./images/helm.tar
   

   These images are quite large, and there will be no output until Docker is done loading.

   Success

   Once the loading finishes, you'll see:

   Loaded image: IMAGE-NAME
   

Tag and push the loaded images to internal registry

Registry Authentication

This step assumes that the current docker client has already authenticated against the internal registry through a regular docker login.

In addition to logging in, if you're using a registry with self-signed certificates, you should also make sure your registry has been added to the 'Insecure Registries' section of the Daemon tab in the Docker settings ui for your current workstation.

For more information about certificates and secure registry concerns, see this article: Test an insecure registry

1. Begin by exporting a pair of variables to your shell to be reused throughout this process. In your terminal, run the following two commands:

   export INTERNAL_REGISTRY=INTERNAL-REGISTRY
   

   export PROJECT=PROJECT-NAME
   

   Where:

   • INTERNAL-REGISTRY is the domain of your internal registry - if you are using Harbor, this must correspond to the URL (without scheme)
   • PROJECT-NAME is the name of the project in your registry. If the project does not exist already you will need to make it.

2. The .tar file you downloaded contains a directory called images. You need to extract the tag of each image so that you can appropriately tag the images with the internal registry and project name details from the last step.

   To do this, run the following command for each of the images in the /images/ directory:

   cat ./images/IMAGE.tar.name | cut -d ':' -f 2
   

   Where:

   • IMAGE is one of the *.tar.name files inside the images folder

   Take note of the result for each image - this is corresponding IMAGE-TAG that will be used with each image in the next steps.

3. Tag the images so their names include the internal registry address:

   Using Harbor (internal registry)

   docker tag concourse/concourse:IMAGE-TAG $INTERNAL_REGISTRY/$PROJECT/concourse:IMAGE-TAG
   docker tag concourse/postgres:IMAGE-TAG $INTERNAL_REGISTRY/$PROJECT/postgres:IMAGE-TAG
   docker tag concourse/helm:IMAGE-TAG $INTERNAL_REGISTRY/$PROJECT/helm:IMAGE-TAG
   

   Using Docker Hub

   docker tag concourse/concourse:IMAGE-TAG USERNAME/concourse:IMAGE-TAG
   docker tag concourse/postgres:IMAGE-TAG USERNAME/postgres:IMAGE-TAG
   docker tag concourse/helm:IMAGE-TAG USERNAME/helm:IMAGE-TAG
   

   Where:

   • IMAGE-TAG is the corresponding result from step 2.
   • (in the Docker Hub example) USERNAME is your Docker Hub username

4. Push the images to the internal registry by running the following commands in your terminal:

   Using Harbor (internal registry)

   docker push $INTERNAL_REGISTRY/$PROJECT/concourse:IMAGE-TAG
   docker push $INTERNAL_REGISTRY/$PROJECT/postgres:IMAGE-TAG
   docker push $INTERNAL_REGISTRY/$PROJECT/helm:IMAGE-TAG
   

   Using Docker Hub

   docker push USERNAME/concourse:IMAGE-TAG
   docker push USERNAME/postgres:IMAGE-TAG
   docker push USERNAME/helm:IMAGE-TAG
   

   Where:

   • IMAGE-TAG is the corresponding result from step 2.
   • (in the Docker Hub example) USERNAME is your Docker Hub username

   You must have the necessary credentials (and authorization) to push to the targetted project.

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Get previous deployment values

Helm uses a set of configuration values to template the different Kubernetes objects that Concourse requires into a release. In order to ensure you maintain the exact same configuration between the current version of Concourse and the upgraded version you are about to deploy, it is important to know what configuration is already deployed.

Version Control

Pivotal recommends checking in these configuration values to a source control management (SCM) system like git so that you can track changes over time. If you have your configuration values in to an SCM system, check them out to your local machine so that they can be updated now.

If you're unsure of what has been deployed, and don't have access to the values files locally, you can fetch the deployment values that your existing release is using by running the helm get values command. This will allow you to recreate the exact configuration with your upgraded release.

1. Get your previous deployment-values.yml file from SCM, or download it using this command:

   helm get values RELEASE-NAME > deployment-values.yml
   

   Where:

   • RELEASE-NAME is the name of your existing Concourse release. Discover this by running the helm list command and looking for a chart that starts with concourse.

2. Open the file in your favorite text editor. For example, with vim:

   vim deployment-values.yml
   

3. Change the imageTag value to match the new version of Concourse. For example, using the v5.5.8 Helm Chart, this image tag will be 5.5.8-ubuntu.

   The following is a sample snippet; make sure the rest of the file you edit reflects your existing Concourse deployment:

   ---
   image: INTERNAL_REGISTRY/PROJECT/concourse
   imageTag: 5.5.8-ubuntu
   imagePullSecrets: ["regcred"] #remove this line for public image registry
   postgresql:
       image:
           registry: INTERNAL_REGISTRY
           repository: PROJECT/postgres
           tag: POSTGRES-IMAGE-TAG
           pullSecrets: ["regcred"] # remove for public image registry
   

   Where:

   • INTERNAL-REGISTRY/PROJECT is your registry address and project.

   • imagePullSecrets is the pull secret listed under the key spec.template.spec in the following file:

     helm init --tiller-image $INTERNAL_REGISTRY/$PROJECT/helm:IMAGE-TAG --service-account tiller --dry-run --debug > tiller.yml
     

     Remove if using a public repository.

   • POSTGRES-IMAGE-TAG is the output of

     cat ./images/postgres.tar.name | cut -d ':' -f 2
     

   • pullSecrets is the pull secret created in step 6a. Remove if using a public repository.

Upgrade

Now that the deployment values are updated, use the helm upgrade command to upgrade your existing release using the new values.

1. Upgrade your release:

   helm upgrade RELEASE-NAME ./charts/ --values ./deployment-values.yml
   

   Where:

   • RELEASE-NAME is the name of your existing Concourse release. Discover this by running the helm list command and looking for a chart that starts with concourse.

   Successful Deployment

   If Kubernetes has accepted the manifest correctly, then you will see the following response followed by more information about your cluster:

   NAME: DEPLOYMENT-NAME
   LAST DEPLOYED: DEPLOYMENT-DATE
   NAMESPACE: default
   STATUS: DEPLOYED
   ...
   

   To determine whether your pods are up and running correctly, use the following command:

   kubectl get pods
   

   This will show you a list of deployed pods as well as their current status. It should look something like this:

   $ kubectl get pods
   NAME                             READY   STATUS    RESTARTS   AGE
   concourse-postgresql-0           1/1     Running   0          15m
   concourse-web-57ccf57f46-zsd25   1/1     Running   0          9m52s
   concourse-worker-0               1/1     Running   0          8m45s
   concourse-worker-1               1/1     Running   0          9m45s