helm-get-started.md

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Installing Weave Flux using Helm	20

Get started with Flux using Helm

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.

Note: If you are using minikube, be sure to start the cluster with --bootstrapper=kubeadm so you are using RBAC.

Download Helm:

• On MacOS:

  brew install kubernetes-helm

• On Linux:

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

Now 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 init --skip-refresh --upgrade --service-account tiller

Install Weave Flux

Add the Flux repository of Weaveworks:

helm repo add weaveworks https://weaveworks.github.io/flux

In this next step you install Weave Flux using helm. Simply

1. Fork flux-helm-test on Github and

2. Install Weave Flux and its 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 or gitlab.com:

     helm install --name flux \
     --set helmOperator.create=true \
     --set git.url=ssh://git@github.com/YOURUSER/flux-helm-test \
     --set helmOperator.git.chartsPath=charts \
     --namespace flux \
     weaveworks/flux

   • 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 chart/flux/README.md 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 get pods --all-namespaces

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 acccess 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 with:

FLUX_POD=$(kubectl get pods --namespace flux -l "app=flux,release=flux" -o jsonpath="{.items[0].metadata.name}")
kubectl -n flux logs $FLUX_POD | grep identity.pub | cut -d '"' -f2

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 name, 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-helm-test/settings/keys/new and paste the key there.)

Once Flux has confirmed access to the repository, it will start deploying the workloads of flux-helm-test. After a while you will be able to see the Helm releases listed like so:

helm list --namespace test

Committing a small change

flux-helm-test is a very simple example in which two services (mongodb and mariadb) 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-helm-test and change the image argument.

Replace YOURUSER in https://github.com/YOURUSER/flux-helm-test/edit/master/releases/mongodb_release.yaml with your Github ID, open the URL in your browser, edit the file, change the image: line to the following:

 image: bitnami/mongodb:3.7.9-r13

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 30 seconds. This can be tweaked easily. By observing the logs you can see when the change landed in in the cluster.

Confirm the change landed

To access our webservice and check out its welcome message, simply run:

kubectl describe -n test deployment.apps/mongodb-database-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 work-flow.

Next

As a next step, you might want to dive deeper into how to control Flux.

For a more advanced Helm setup, take a look at the gitops-helm repository.