Get started with Flux

This short guide shows a self-contained example of Flux and just takes a couple of minutes to get set up. By the end you will have Flux running in your cluster and it will be deploying any code changes for you.

Note: If you would like to install Flux using Helm, refer to the Helm section.

Prerequisites

You will need to have Kubernetes set up. For a quick local test, you can use minikube or kubeadm. Any other Kubernetes setup will work as well though.

A note on GKE with RBAC enabled

If working on e.g. GKE with RBAC enabled, you will need to add a ClusterRoleBinding:

kubectl create clusterrolebinding "cluster-admin-$(whoami)" --clusterrole=cluster-admin --user="$(gcloud config get-value core/account)"

to avoid an error along the lines of:

Error from server (Forbidden): error when creating "deploy/flux-account.yaml":
clusterroles.rbac.authorization.k8s.io "flux" is forbidden: attempt to grant
extra privileges:

Set up Flux

In our example we are going to use flux-get-started. If you want to use that too, be sure to create a fork of it on GitHub.

First, please install fluxctl.

Then, install flux in your Cluster:

fluxctl install --git-url=[email protected]/<your-user>/flux-get-started --git-path=namespaces,workloads --git-email=[email protected] | kubectl apply -f -

--git-path=namespaces,workloads, is meant to exclude Helm manifests. Again, if you want to get started with Helm, please refer to the Helm section.

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

Giving write access

At startup Flux generates a SSH key and logs the public key. Find the SSH public key by installing fluxctl and running:

fluxctl identity

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. See the GitHub docs for more info on how to manage deploy keys.

(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.)

Note: the SSH key must be configured to have R/W access to the repository. More specifically, the SSH key must be able to create and update tags. E.g. in Gitlab, that means it requires Maintainer permissions. The Developer permission can create tags, but not update them.

Committing a small change

In this example we are using a simple example of a webservice and change its configuration to use a different message. The easiest way is to edit your fork of flux-get-started and change the PODINFO_UI_COLOR env var to blue.

Replace YOURUSER in https://github.com/YOURUSER/flux-get-started/blob/master/workloads/podinfo-dep.yaml with your GitHub ID), open the URL in your browser, edit the file, change the env var value and commit the file.

You can check out the Flux logs with:

kubectl -n default logs deployment/flux -f

The default sync frequency is 5 minutes. 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 -n demo port-forward deployment/podinfo 9898:9898 &
curl localhost:9898

Notice the updated color value in the JSON reply.

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.

As a next step, you might want to dive deeper into how to control Flux, or go through our hands-on tutorial about driving Flux, e.g. automations, annotations and locks.