data.gov.uk Helm Charts

Getting started

See Helm's documentation to get started with Helm.

See the GOV.UK Kubernetes cluster docs for an introduction to the cluster or ask #govuk-platform-engineering in Slack.

Local development uses k3d which runs a Kubernetes cluster locally using Docker.

Prerequisites

1. Install Helm

brew install helm

2. Install Docker

Install from here

3. Install k3d

brew install k3d

4. Install kubectl

brew install kubectl

5. Clone the repository

git clone git@github.com:alphagov/govuk-dgu-charts.git

Setting up a local CKAN cluster

Advantage of using k3d is that we don't need to worry about creating an ingress controller. This aligns with how we run the cluster in EKS as that manages creation of the ingress controller for us.

1. Create the k3d cluster

k3d cluster create local-ckan --api-port 6550 -p "8081:80@loadbalancer" --registry-create local-registry

2. Switch kubectl to point to your local cluster:

kubectl config use-context k3d-local-ckan

3. Locate the port the registry is running on:

docker ps -f name=local-registry

The remaining steps will assume our local registry is running on localhost:53492

4. Build a docker image

If we want to push an image to our local registry we have to tag our image. See here for background on local Docker registries.

So if our local registry is running at localhost:53492 and we want to build ckan 2.10.4 we have to tag our image as follows:

docker build -t localhost:53492/ckan:2.10.4 -f docker/ckan/2.10.4.Dockerfile .

Note: for Publish and Find build the dev.Dockerfile version

docker build -t localhost:53492/datagovuk_publish:dev -f docker/dev.Dockerfile .

5. Push the image to our local registry

docker push localhost:53492/ckan:2.10.4

6. Use the image in our Helm chart

Currently govuk-dgu-charts/charts/ckan/values.yaml points to the test environment:

environment: test

ckan:
  replicaCount: 1
  ...

Update govuk-dgu-charts/ckan/images/test/ckan.yaml with our new image so it looks like this:

repository: local-registry:53492/ckan
tag: 2.10.4
branch: main

Note that local-registry matches the name of the registry we passed in step 1. If we want to use a different image from a different environment then set environment appropriately.

7. Apply the local dev Helm Chart

kubectl apply -f local-dev.yaml

This sets up some initial configuration in the cluster.

8. Install the application Helm charts

helm install ckan-dev ./charts/ckan/
helm install datagovuk-dev ./charts/datagovuk/

Now your local CKAN deployment will use the localhost:54392/ckan.2.10.4 image.

Use a nicer URL

Update /etc/hosts and add ckan.dev.govuk.digital and find.data.gov.uk after kubernetes.docker.internal on the sameline in the /etc/hosts file

Test Helm chart in EKS

1. update the targetRevision in ckan-application.yaml or datagovuk-application.yaml to be the branch you want to test against.
2. update the target revision in Argo on dgu-app-of-apps to be the branch you want to test, normally on the Integration cluster.
3. after testing is complete remember to set the target revision back to main in dgu-app-of-apps.
4. if you are creating a PR drop the commit which updates the targetRevision in step 1.

Github API token permissions

When creating fine-grained API tokens, ensure that read/write permissions for PRs and Content are allowed (this will allow for PR and commit creation) and that CI user is used to create the PRs.

Schemas

We have several Custom Resource Definitions (CRDs) installed in our Kubernetes clusters, and referenced by the Helm charts in this repository.

We use kubeconform to validate our Kubernetes manifests against schemas for those resources. This helps us ensure that our Helm charts are correct.

kubeconform runs in a GitHub Action as a pre-merge check and can also be run locally.

You can run the validation tests locally by installing kubeconform and running

mkdir helm-dist
for c in charts/*; do
  helm template "$(basename "$c")" "$c" --output-dir helm-dist
done

kubeconform -schema-location default \
-schema-location "https://raw.githubusercontent.com/datreeio/CRDs-catalog/main/{{.Group}}/{{.ResourceKind}}_{{.ResourceAPIVersion}}.json" \
-summary helm-dist

Team

GOV.UK Platform Engineering team looks after this repo. If you're inside GDS, you can find us in #govuk-platform-engineering.