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Get started with Flux using Helm

🛑 Upgrade Advisory

This documentation is for Flux (v1) which has reached its end-of-life in November 2022.

We strongly recommend you familiarise yourself with the newest Flux and migrate as soon as possible.

For documentation regarding the latest Flux, please refer to this section.

If you are using Helm already, this guide is for you. By the end you will have Helm installing Flux in the cluster and deploying any code changes for you.

If you are looking for more generic notes for how to install Flux using Helm, we collected them in the chart's README.

Prerequisites

You will need to have Kubernetes set up. To get up and running fast, you might want to use minikube or kubeadm. Any other Kubernetes setup will work as well though.

Download Helm v3:

  • On MacOS:

    brew install helm

  • On Linux: Download the latest release, unpack the tarball and put the binary in your $PATH.

If you are using Helm v2 you have to create a service account and a cluster role binding for Tiller:

kubectl -n kube-system create sa tiller

kubectl create clusterrolebinding tiller-cluster-rule \
    --clusterrole=cluster-admin \
    --serviceaccount=kube-system:tiller

Deploy Tiller in kube-system namespace (Helm v2 only):

helm init --skip-refresh --upgrade --service-account tiller --history-max 10

⚠ Note: This is a quick guide and by no means a production ready Tiller setup, please look into 'Securing your Helm installation' and be aware of the --history-max flag before promoting to production.

Install Flux

Add the Flux repository:

helm repo add fluxcd https://charts.fluxcd.io

Apply the Helm Release CRD:

kubectl apply -f https://raw.githubusercontent.com/fluxcd/helm-operator/master/deploy/crds.yaml

In this next step you install Flux using helm. Simply

  1. Fork fluxcd/flux-get-started on GitHub and replace the fluxcd with your GitHub username in here

  2. Create the flux namespace:

    kubectl create namespace flux

  3. Install Flux and the Helm Operator by specifying your fork URL:

    Just make sure you replace YOURUSER with your GitHub username in the command below:

    • Using a public git server from bitbucket.com, github.com, gitlab.com, dev.azure.com, or vs-ssh.visualstudio.com:

      helm upgrade -i flux fluxcd/flux \
   --set git.url=git@github.com:YOURUSER/flux-get-started \
   --namespace flux

 helm upgrade -i helm-operator fluxcd/helm-operator \
   --set git.ssh.secretName=flux-git-deploy \
   --namespace flux

      ⚠ Note: By default the helm-operator chart will install with support for both Helm v2 (which requires Tiller) and v3. You can target specific versions by setting the helm.versions value, e.g. --set helm.versions=v3.

    • Using a private git server:

      When deploying from a private repo, the known_hosts of the git server needs to be configured into a kubernetes configmap so that StrictHostKeyChecking is respected. See the README of the chart for further installation instructions in this case.

Allow some time for all containers to get up and running. If you're impatient, run the following command and see the pod creation process.

watch kubectl -n flux get pods

You will notice that flux and flux-helm-operator will start turning up in the flux namespace.

Giving write access

For the real benefits of GitOps, Flux will need access to your git repository to update configuration if necessary. To facilitate that you will need to add a deploy key to your fork of the repository.

This is pretty straight-forward as Flux generates a SSH key and logs the public key at startup. Find the SSH public key by installing fluxctl and running:

fluxctl identity --k8s-fwd-ns flux

In order to sync your cluster state with git you need to copy the public key and create a deploy key with write access on your GitHub repository.

Open GitHub, navigate to your fork, go to Setting > Deploy keys, click on Add deploy key, give it a Title, check Allow write access, paste the Flux public key and click Add key.

(Or replace YOURUSER with your GitHub ID in this url: https://github.com/YOURUSER/flux-get-started/settings/keys/new and paste the key there.)

Once Flux has confirmed access to the repository, it will start deploying the workloads of flux-get-started. After a while you will be able to see the Helm releases deployed by Flux (which are deployed into the demo namespace) listed like so:

helm list --namespace demo

Committing a small change

flux-get-started is a simple example in which three services (mongodb, redis and ghost) are deployed. Here we will simply update the version of mongodb to a newer version to see if Flux will pick this up and update our cluster.

The easiest way is to update your fork of flux-get-started and change the image argument.

Replace YOURUSER in https://github.com/YOURUSER/flux-get-started/edit/master/releases/mongodb.yaml with your GitHub ID, open the URL in your browser, edit the file, change the tag: line to the following:

  values:
    image:
      repository: bitnami/mongodb
      tag: 4.0.14

Commit the change to your master branch. It will now get automatically deployed to your cluster.

You can check out the Flux logs with:

kubectl -n flux logs deployment/flux -f

The default sync frequency for Flux using the Helm chart is five minutes. This can be tweaked easily. By observing the logs you can see when the change landed in the cluster.

Confirm the change landed by checking the demo namespace that Flux is deploying to:

kubectl describe -n demo deployment/mongodb | grep Image

Conclusion

As you can see, the actual steps to set up Flux, get our app deployed, give Flux access to it and see modifications land are very straight-forward and are a quite natural workflow.

A more advanced setup

For a more advanced Helm setup, take a look at the fluxcd/helm-operator-get-started repository.