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https://github.com/fluxcd/helm-operator-get-started

Managing Helm releases with Flux Helm Operator
https://github.com/fluxcd/helm-operator-get-started

ci-cd gitops helm kubernetes secrets-management

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Managing Helm releases with Flux Helm Operator

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README 

        
# Managing Helm releases the GitOps way



## We are moving to Flux v2



> ⚠️ Please note: In preparation of [Flux v2](https://toolkit.fluxcd.io/) GA this repository with Flux v1 examples has been archived. The Flux v2 equivalent of what is shown here can be found at [flux2-kustomize-helm-example](https://github.com/fluxcd/flux2-kustomize-helm-example).

>

> Thanks a lot for your interest.



## What is GitOps?



GitOps is a way to do Continuous Delivery, it works by using Git as a source of truth for declarative infrastructure and workloads.

For Kubernetes this means using `git push` instead of `kubectl create/apply` or `helm install/upgrade`.



In a traditional CICD pipeline, CD is an implementation extension powered by the

continuous integration tooling to promote build artifacts to production.

In the GitOps pipeline model, any change to production must be committed in source control

(preferable via a pull request) prior to being applied on the cluster.

This way rollback and audit logs are provided by Git.

If the entire production state is under version control and described in a single Git repository, when disaster strikes,

the whole infrastructure can be quickly restored from that repository.



To better understand the benefits of this approach to CD and what the differences between GitOps and

Infrastructure-as-Code tools are, head to the Weaveworks website and read [GitOps - What you need to know](https://www.weave.works/technologies/gitops/) article.



In order to apply the GitOps pipeline model to Kubernetes you need three things:



* a Git repository with your workloads definitions in YAML format, Helm charts and any other Kubernetes custom resource that defines your cluster desired state (I will refer to this as the *config* repository)

* a container registry where your CI system pushes immutable images (no *latest* tags, use *semantic versioning* or git *commit sha*)

* an operator that runs in your cluster and does a two-way synchronization:

    * watches the registry for new image releases and based on deployment policies updates the workload definitions with the new image tag and commits the changes to the config repository

    * watches for changes in the config repository and applies them to your cluster



I will be using GitHub to host the config repo, Docker Hub as the container registry and Flux as the GitOps Kubernetes Operator.



![gitops](https://github.com/fluxcd/helm-operator-get-started/blob/master/diagrams/flux-helm-operator-registry.png)



### Prerequisites



You'll need a Kubernetes cluster v1.11 or newer, a GitHub account, git and kubectl installed locally.



Install Helm v3 and fluxctl for macOS with Homebrew:



```sh

brew install helm fluxctl

```



On Windows you can use Chocolatey:



```sh

choco install kubernetes-helm fluxctl

```



On Linux you can download the [helm](https://github.com/helm/helm/releases)

and [fluxctl](https://github.com/fluxcd/flux/releases) binaries from GitHub.



### Install Flux



The first step in automating Helm releases with [Flux](https://github.com/fluxcd/flux) is to create a Git repository with your charts source code.



On GitHub, fork this repository and clone it locally

(replace `fluxcd` with your GitHub username): 



```sh

git clone https://github.com/fluxcd/helm-operator-get-started

cd helm-operator-get-started

```



*If you fork, update the release definitions with your Docker Hub repository and GitHub username located in

\releases\(dev/stg/prod)\podinfo.yaml in your master branch before proceeding.



Add FluxCD repository to Helm repos:



```bash

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

```



Create the `fluxcd` namespace:



```sh

kubectl create ns fluxcd

```



Install Flux by specifying your fork URL (replace `fluxcd` with your GitHub username): 



```bash

helm upgrade -i flux fluxcd/flux --wait \

--namespace fluxcd \

--set [email protected]:fluxcd/helm-operator-get-started

```



Install the `HelmRelease` Kubernetes custom resource definition:



```sh

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

```



Install Flux Helm Operator with ***Helm v3*** support:



```bash

helm upgrade -i helm-operator fluxcd/helm-operator --wait \

--namespace fluxcd \

--set git.ssh.secretName=flux-git-deploy \

--set helm.versions=v3

```



The Flux Helm operator provides an extension to Flux that automates Helm Chart releases for it.

A Chart release is described through a Kubernetes custom resource named HelmRelease.

The Flux daemon synchronizes these resources from git to the cluster,

and the Flux Helm operator makes sure Helm charts are released as specified in the resources.



Note that Flux Helm Operator works with Kubernetes 1.11 or newer.



At startup, Flux generates a SSH key and logs the public key. Find the public key with:



```bash

fluxctl identity --k8s-fwd-ns fluxcd

```



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_, check

_Allow write access_, paste the Flux public key and click _Add key_.



### GitOps pipeline example



The config repo has the following structure:



```

├── charts

│   └── podinfo

│       ├── Chart.yaml

│       ├── README.md

│       ├── templates

│       └── values.yaml

├── hack

│   ├── Dockerfile.ci

│   └── ci-mock.sh

├── namespaces

│   ├── dev.yaml

│   └── stg.yaml

└── releases

    ├── dev

    │   └── podinfo.yaml

    └── stg

        └── podinfo.yaml

```



I will be using [podinfo](https://github.com/stefanprodan/podinfo) to demonstrate a full CI/CD pipeline including promoting releases between environments.



I'm assuming the following Git branching model:

* dev branch (feature-ready state)

* stg branch (release-candidate state)

* master branch (production-ready state)



When a PR is merged in the dev or stg branch will produce a immutable container image as in `repo/app:branch-commitsha`.



Inside the *hack* dir you can find a script that simulates the CI process for dev and stg.

The *ci-mock.sh* script does the following:

* pulls the podinfo source code from GitHub

* generates a random string and modifies the code

* generates a random Git commit short SHA

* builds a Docker image with the format: `yourname/podinfo:branch-sha`

* pushes the image to Docker Hub



Let's create an image corresponding to the `dev` branch (replace `stefanprodan` with your Docker Hub username):



```

$ cd hack && ./ci-mock.sh -r stefanprodan/podinfo -b dev



Sending build context to Docker daemon  4.096kB

Step 1/15 : FROM golang:1.13 as builder

....

Step 9/15 : FROM alpine:3.10

....

Step 12/15 : COPY --from=builder /go/src/github.com/stefanprodan/k8s-podinfo/podinfo .

....

Step 15/15 : CMD ["./podinfo"]

....

Successfully built 71bee4549fb2

Successfully tagged stefanprodan/podinfo:dev-kb9lm91e

The push refers to repository [docker.io/stefanprodan/podinfo]

36ced78d2ca2: Pushed

```



Inside the *charts* directory there is a podinfo Helm chart.

Using this chart I want to create a release in the `dev` namespace with the image I've just published to Docker Hub.

Instead of editing the `values.yaml` from the chart source, I create a `HelmRelease` definition (located in /releases/dev/podinfo.yaml):



```yaml

apiVersion: helm.fluxcd.io/v1

kind: HelmRelease

metadata:

  name: podinfo-dev

  namespace: dev

  annotations:

    fluxcd.io/automated: "true"

    filter.fluxcd.io/chart-image: glob:dev-*

spec:

  releaseName: podinfo-dev

  chart:

    git: [email protected]:fluxcd/helm-operator-get-started

    path: charts/podinfo

    ref: master

  values:

    image:

      repository: stefanprodan/podinfo

      tag: dev-kb9lm91e

    replicaCount: 1

```



Flux Helm release fields:



* `metadata.name` is mandatory and needs to follow Kubernetes naming conventions

* `metadata.namespace` is optional and determines where the release is created

* `spec.releaseName` is optional and if not provided the release name will be $namespace-$name

* `spec.chart.path` is the directory containing the chart, given relative to the repository root

* `spec.values` are user customizations of default parameter values from the chart itself



The options specified in the HelmRelease `spec.values` will override the ones in `values.yaml` from the chart source.



With the `fluxcd.io/automated` annotations I instruct Flux to automate this release.

When a new tag with the prefix `dev` is pushed to Docker Hub, Flux will update the image field in the yaml file,

will commit and push the change to Git and finally will apply the change on the cluster.



![gitops-automation](https://github.com/stefanprodan/openfaas-flux/blob/master/docs/screens/flux-helm-image-update.png)



When the `podinfo-dev` HelmRelease object changes inside the cluster,

Kubernetes API will notify the Flux Helm Operator and the operator will perform a Helm release upgrade.



```

$ helm -n dev history podinfo-dev



REVISION	STATUS    	CHART        	DESCRIPTION

1       	superseded	podinfo-0.2.0	Install complete

2       	deployed  	podinfo-0.2.0	Upgrade complete

```



The Flux Helm Operator reacts to changes in the HelmRelease collection but will also detect changes in the charts source files.

If I make a change to the podinfo chart, the operator will pick that up and run an upgrade.



![gitops-chart-change](https://github.com/stefanprodan/openfaas-flux/blob/master/docs/screens/flux-helm-chart-update.png)



```

$ helm -n dev history podinfo-dev



REVISION	STATUS    	CHART        	DESCRIPTION

1       	superseded	podinfo-0.2.0	Install complete

2       	superseded	podinfo-0.2.0	Upgrade complete

3       	deployed  	podinfo-0.2.1	Upgrade complete

```



Now let's assume that I want to promote the code from the `dev` branch into a more stable environment for others to test it.

I would create a release candidate by merging the podinfo code from `dev` into the `stg` branch.

The CI would kick in and publish a new image:



```bash

$ cd hack && ./ci-mock.sh -r stefanprodan/podinfo -b stg



Successfully tagged stefanprodan/podinfo:stg-9ij63o4c

The push refers to repository [docker.io/stefanprodan/podinfo]

8f21c3669055: Pushed

```



Assuming the staging environment has some sort of automated load testing in place,

I want to have a different configuration than dev:



```yaml

apiVersion: helm.fluxcd.io/v1

kind: HelmRelease

metadata:

  name: podinfo-rc

  namespace: stg

  annotations:

    fluxcd.io/automated: "true"

    filter.fluxcd.io/chart-image: glob:stg-*

spec:

  releaseName: podinfo-rc

  chart:

    git: [email protected]:fluxcd/helm-operator-get-started

    path: charts/podinfo

    ref: master

  values:

    image:

      repository: stefanprodan/podinfo

      tag: stg-9ij63o4c

    replicaCount: 2

    hpa:

      enabled: true

      maxReplicas: 10

      cpu: 50

      memory: 128Mi

```



With Flux Helm releases it's easy to manage different configurations per environment.

When adding a new option in the chart source make sure it's turned off by default so it will not affect all environments.



If I want to create a new environment, let's say for hotfixes testing, I would do the following:

* create a new namespace definition in `namespaces/hotfix.yaml`

* create a dir `releases/hotfix`

* create a HelmRelease named `podinfo-hotfix`

* set the automation filter to `glob:hotfix-*`

* make the CI tooling publish images from my hotfix branch to `stefanprodan/podinfo:hotfix-sha`



### Production promotions with sem ver



For production, instead of tagging the images with the Git commit, I will use [Semantic Versioning](https://semver.org).



Let's assume that I want to promote the code from the `stg` branch into `master` and do a production release.

After merging `stg` into `master` via a pull request, I would cut a release by tagging `master` with version `0.4.10`.



When I push the git tag, the CI will publish a new image in the `repo/app:git_tag` format:



```bash

$ cd hack && ./ci-mock.sh -r stefanprodan/podinfo -v 0.4.10



Successfully built f176482168f8

Successfully tagged stefanprodan/podinfo:0.4.10

```



If I want to automate the production deployment based on version tags, I would use `semver` filters instead of `glob`:



```yaml

apiVersion: helm.fluxcd.io/v1

kind: HelmRelease

metadata:

  name: podinfo-prod

  namespace: prod

  annotations:

    fluxcd.io/automated: "true"

    filter.fluxcd.io/chart-image: semver:~0.4

spec:

  releaseName: podinfo-prod

  chart:

    git: [email protected]:fluxcd/helm-operator-get-started

    path: charts/podinfo

    ref: master

  values:

    image:

      repository: stefanprodan/podinfo

      tag: 0.4.10

    replicaCount: 3

```



Now if I release a new patch, let's say `0.4.11`, Flux will automatically deploy it.



```bash

$ cd hack && ./ci-mock.sh -r stefanprodan/podinfo -v 0.4.11



Successfully tagged stefanprodan/podinfo:0.4.11

```



![gitops-semver](https://github.com/stefanprodan/openfaas-flux/blob/master/docs/screens/flux-helm-semver.png)



### Managing Kubernetes secrets



In order to store secrets safely in a public Git repo you can use the Bitnami [Sealed Secrets controller](https://github.com/bitnami-labs/sealed-secrets)

and encrypt your Kubernetes Secrets into SealedSecrets.

The SealedSecret can be decrypted only by the controller running in your cluster.



The Sealed Secrets Helm chart is available on [Helm Hub](https://hub.helm.sh/charts/stable/sealed-secrets),

so I can use the Helm repository instead of a git repo. This is the sealed-secrets controller release:



```yaml

apiVersion: helm.fluxcd.io/v1

kind: HelmRelease

metadata:

  name: sealed-secrets

  namespace: adm

spec:

  releaseName: sealed-secrets

  chart:

    repository: https://kubernetes-charts.storage.googleapis.com/

    name: sealed-secrets

    version: 1.6.1

```



Note that this release is not automated, since this is a critical component I prefer to update it manually.



Install the kubeseal CLI:



```bash

brew install kubeseal

```



At startup, the sealed-secrets controller generates a RSA key and logs the public key.

Using kubeseal you can save your public key as `pub-cert.pem`,

the public key can be safely stored in Git, and can be used to encrypt secrets without direct access to the Kubernetes cluster:



```bash

kubeseal --fetch-cert \

--controller-namespace=adm \

--controller-name=sealed-secrets \

> pub-cert.pem

```



You can generate a Kubernetes secret locally with kubectl and encrypt it with kubeseal:



```bash

kubectl -n dev create secret generic basic-auth \

--from-literal=user=admin \

--from-literal=password=admin \

--dry-run \

-o json > basic-auth.json



kubeseal --format=yaml --cert=pub-cert.pem < basic-auth.json > basic-auth.yaml

```



This generates a custom resource of type `SealedSecret` that contains the encrypted credentials:



```yaml

apiVersion: bitnami.com/v1alpha1

kind: SealedSecret

metadata:

  name: basic-auth

  namespace: adm

spec:

  encryptedData:

    password: AgAR5nzhX2TkJ.......

    user: AgAQDO58WniIV3gTk.......

```



Delete the `basic-auth.json` file and push the `pub-cert.pem` and `basic-auth.yaml` to Git:



```bash

rm basic-auth.json

mv basic-auth.yaml /releases/dev/



git commit -a -m "Add basic auth credentials to dev namespace" && git push

```



Flux will apply the sealed secret on your cluster and sealed-secrets controller will then decrypt it into a

Kubernetes secret.



![SealedSecrets](https://github.com/fluxcd/helm-operator-get-started/blob/master/diagrams/flux-helm-operator-sealed-secrets.png)



To prepare for disaster recovery you should backup the sealed-secrets controller private key with:



```bash

kubectl get secret -n adm sealed-secrets-key -o yaml --export > sealed-secrets-key.yaml

```



To restore from backup after a disaster, replace the newly-created secret and restart the controller:



```bash

kubectl replace secret -n adm sealed-secrets-key -f sealed-secrets-key.yaml

kubectl delete pod -n adm -l app=sealed-secrets

```



### Getting Help



If you have any questions about Helm Operator and continuous delivery:



- Read [the Helm Operator docs](https://docs.fluxcd.io/projects/helm-operator/en/latest/).

- Read [the Flux integration with the Helm operator docs](https://docs.fluxcd.io/en/latest/references/helm-operator-integration.html).

- Invite yourself to the CNCF community

  slack and ask a question on the [#flux](https://cloud-native.slack.com/messages/flux/)

  channel.

- To be part of the conversation about Helm Operator's development, join the

  [flux-dev mailing list](https://lists.cncf.io/g/cncf-flux-dev).

- [File an issue.](https://github.com/fluxcd/flux/issues/new)



Your feedback is always welcome!