Edit

Tutorial: Deploy applications using GitOps with Flux v2

  • Article

This tutorial describes how to use GitOps in a Kubernetes cluster. GitOps with Flux v2 is enabled as a cluster extension in Azure Arc-enabled Kubernetes clusters or Azure Kubernetes Service (AKS) clusters. After the microsoft.flux cluster extension is installed, you can create one or more fluxConfigurations resources that sync your Git repository sources to the cluster and reconcile the cluster to the desired state. With GitOps, you can use your Git repository as the source of truth for cluster configuration and application deployment.

In this tutorial, we use an example GitOps configuration with two kustomizations, so that you can see how one kustomization can have a dependency on another. You can add more kustomizations and dependencies as needed, depending on your scenario.

Before you dive in, take a moment to learn how GitOps with Flux works conceptually.

Tip

While the source in this tutorial is a Git repository, Flux also provides support for other common file sources such as Helm repositories, Buckets, and Azure Blob Storage.

You can also create Flux configurations by using Bicep, ARM templates, or Terraform AzAPI provider. For more information, see Microsoft.KubernetesConfiguration fluxConfigurations.

Important

The microsoft.flux extension released major version 1.0.0. This includes the multi-tenancy feature. If you have existing GitOps Flux v2 configurations that use a previous version of the microsoft.flux extension, you can upgrade to the latest version manually using the Azure CLI: az k8s-extension create -g <RESOURCE_GROUP> -c <CLUSTER_NAME> -n flux --extension-type microsoft.flux -t <CLUSTER_TYPE> (use -t connectedClusters for Arc clusters and -t managedClusters for AKS clusters).

Tip

When using this extension with AKS hybrid clusters provisioned from Azure you must set --cluster-type to use provisionedClusters and also add --cluster-resource-provider microsoft.hybridcontainerservice to the command. Installing Azure Arc extensions on AKS hybrid clusters provisioned from Azure is currently in preview.

Prerequisites

To deploy applications using GitOps with Flux v2, you need:

For Azure Arc-enabled Kubernetes clusters

For Azure Kubernetes Service clusters

  • An MSI-based AKS cluster that's up and running.

    Important

    Ensure that the AKS cluster is created with MSI (not SPN), because the microsoft.flux extension won't work with SPN-based AKS clusters. For new AKS clusters created with az aks create, the cluster will be MSI-based by default. For already created SPN-based clusters that need to be converted to MSI, run az aks update -g $RESOURCE_GROUP -n $CLUSTER_NAME --enable-managed-identity. For more information, see Use a managed identity in AKS.

  • Read and write permissions on the Microsoft.ContainerService/managedClusters resource type. If using AKS hybrid clusters provisioned from Azure (preview), read and write permissions on the Microsoft.ContainerService/provisionedClusters resource type).

Common to both cluster types

  • Read and write permissions on these resource types:

    • Microsoft.KubernetesConfiguration/extensions
    • Microsoft.KubernetesConfiguration/fluxConfigurations

  • Azure CLI version 2.15 or later. Install the Azure CLI or use the following commands to update to the latest version:

    az version
az upgrade

  • The Kubernetes command-line client, kubectl. kubectl is already installed if you use Azure Cloud Shell.

    Install kubectl locally using the az aks install-cli command:

    az aks install-cli

  • Registration of the following Azure resource providers:

    az provider register --namespace Microsoft.Kubernetes
az provider register --namespace Microsoft.ContainerService
az provider register --namespace Microsoft.KubernetesConfiguration

    Registration is an asynchronous process and should finish within 10 minutes. To monitor the registration process, use the following command:

    az provider show -n Microsoft.KubernetesConfiguration -o table

Namespace                          RegistrationPolicy    RegistrationState
---------------------------------  --------------------  -------------------
Microsoft.KubernetesConfiguration  RegistrationRequired  Registered

Version and region support

GitOps is currently supported in all regions that Azure Arc-enabled Kubernetes supports. GitOps is currently supported in a subset of the regions that AKS supports. The GitOps service is adding new supported regions on a regular cadence.

The most recent version of the Flux v2 extension and the two previous versions (N-2) are supported. We generally recommend that you use the most recent version of the extension.

Network requirements

The GitOps agents require outbound (egress) TCP to the repo source on either port 22 (SSH) or port 443 (HTTPS) to function. The agents also require access to the following outbound URLs:

Endpoint (DNS) Description
https://management.azure.com Required for the agent to communicate with the Kubernetes Configuration service.
https://<region>.dp.kubernetesconfiguration.azure.com Data plane endpoint for the agent to push status and fetch configuration information. Depends on <region> (the supported regions mentioned earlier).
https://login.microsoftonline.com Required to fetch and update Azure Resource Manager tokens.
https://mcr.microsoft.com Required to pull container images for Flux controllers.

Enable CLI extensions

Install the latest k8s-configuration and k8s-extension CLI extension packages:

az extension add -n k8s-configuration
az extension add -n k8s-extension

To update these packages to the latest versions:

az extension update -n k8s-configuration
az extension update -n k8s-extension

To see a list of all installed Azure CLI extensions and their versions, use the following command:

az extension list -o table

Experimental   ExtensionType   Name                   Path                                                       Preview   Version
-------------  --------------  -----------------      -----------------------------------------------------      --------  --------
False          whl             connectedk8s           C:\Users\somename\.azure\cliextensions\connectedk8s         False     1.2.7
False          whl             k8s-configuration      C:\Users\somename\.azure\cliextensions\k8s-configuration    False     1.5.0
False          whl             k8s-extension          C:\Users\somename\.azure\cliextensions\k8s-extension        False     1.1.0

Tip

For help resolving any errors, see the Flux v2 suggestions in Azure Arc-enabled Kubernetes and GitOps troubleshooting.

Apply a Flux configuration

Use the k8s-configuration Azure CLI extension or the Azure portal to enable GitOps in an AKS or Arc-enabled Kubernetes cluster. For a demonstration, use the public gitops-flux2-kustomize-helm-mt repository.

Important

The demonstration repo is designed to simplify your use of this tutorial and illustrate some key principles. To keep up to date, the repo can get breaking changes occasionally from version upgrades. These changes won't affect your new application of this tutorial, only previous tutorial applications that have not been deleted. To learn how to handle these changes please see the breaking change disclaimer.

The following example uses the az k8s-configuration create command to apply a Flux configuration to a cluster, using the following values and settings:

  • The resource group that contains the cluster is flux-demo-rg.
  • The name of the Azure Arc cluster is flux-demo-arc.
  • The cluster type is Azure Arc (-t connectedClusters), but this example also works with AKS (-t managedClusters) and AKS hybrid clusters provisioned from Azure (-t provisionedClusters).
  • The name of the Flux configuration is cluster-config.
  • The namespace for configuration installation is cluster-config.
  • The URL for the public Git repository is https://github.com/Azure/gitops-flux2-kustomize-helm-mt.
  • The Git repository branch is main.
  • The scope of the configuration is cluster. This scope gives the operators permissions to make changes throughout cluster. To use namespace scope with this tutorial, see the changes needed.
  • Two kustomizations are specified with names infra and apps. Each is associated with a path in the repository.
  • The apps kustomization depends on the infra kustomization. (The infra kustomization must finish before the apps kustomization runs.)
  • Set prune=true on both kustomizations. This setting ensures that the objects that Flux deployed to the cluster will be cleaned up if they're removed from the repository, or if the Flux configuration or kustomizations are deleted.
az k8s-configuration flux create -g flux-demo-rg \
-c flux-demo-arc \
-n cluster-config \
--namespace cluster-config \
-t connectedClusters \
--scope cluster \
-u https://github.com/Azure/gitops-flux2-kustomize-helm-mt \
--branch main  \
--kustomization name=infra path=./infrastructure prune=true \
--kustomization name=apps path=./apps/staging prune=true dependsOn=\["infra"\]

The microsoft.flux extension will be installed on the cluster (if it hasn't already been installed due to a previous GitOps deployment).

Tip

The az k8s-configuration create command deploys the microsoft.flux extension to the cluster and creates the configuration. In some scenarios, you may want to create the flux extension instance separately before you create your configuration resources. To do so, use the az k8s-extension create command to create an instance of the extension on your cluster.

When the flux configuration is first installed, the initial compliance state may be Pending or Non-compliant because reconciliation is still ongoing. After a minute or so, query the configuration again to see the final compliance state.

az k8s-configuration flux show -g flux-demo-rg -c flux-demo-arc -n cluster-config -t connectedClusters

To confirm that the deployment was successful, run the following command:

az k8s-configuration flux show -g flux-demo-rg -c flux-demo-arc -n cluster-config -t connectedClusters

With a successful deployment the following namespaces are created:

  • flux-system: Holds the Flux extension controllers.
  • cluster-config: Holds the Flux configuration objects.
  • nginx, podinfo, redis: Namespaces for workloads described in manifests in the Git repository.

To confirm the namespaces, run the following command:

kubectl get namespaces

The flux-system namespace contains the Flux extension objects:

  • Azure Flux controllers: fluxconfig-agent, fluxconfig-controller
  • OSS Flux controllers: source-controller, kustomize-controller, helm-controller, notification-controller

The Flux agent and controller pods should be in a running state. Confirm this using the following command:

kubectl get pods -n flux-system

NAME                                      READY   STATUS    RESTARTS   AGE
fluxconfig-agent-9554ffb65-jqm8g          2/2     Running   0          21m
fluxconfig-controller-9d99c54c8-nztg8     2/2     Running   0          21m
helm-controller-59cc74dbc5-77772          1/1     Running   0          21m
kustomize-controller-5fb7d7b9d5-cjdhx     1/1     Running   0          21m
notification-controller-7d45678bc-fvlvr   1/1     Running   0          21m
source-controller-df7dc97cd-4drh2         1/1     Running   0          21m

The namespace cluster-config has the Flux configuration objects.

kubectl get crds

NAME                                                   CREATED AT
alerts.notification.toolkit.fluxcd.io                  2022-04-06T17:15:48Z
arccertificates.clusterconfig.azure.com                2022-03-28T21:45:19Z
azureclusteridentityrequests.clusterconfig.azure.com   2022-03-28T21:45:19Z
azureextensionidentities.clusterconfig.azure.com       2022-03-28T21:45:19Z
buckets.source.toolkit.fluxcd.io                       2022-04-06T17:15:48Z
connectedclusters.arc.azure.com                        2022-03-28T21:45:19Z
customlocationsettings.clusterconfig.azure.com         2022-03-28T21:45:19Z
extensionconfigs.clusterconfig.azure.com               2022-03-28T21:45:19Z
fluxconfigs.clusterconfig.azure.com                    2022-04-06T17:15:48Z
gitconfigs.clusterconfig.azure.com                     2022-03-28T21:45:19Z
gitrepositories.source.toolkit.fluxcd.io               2022-04-06T17:15:48Z
helmcharts.source.toolkit.fluxcd.io                    2022-04-06T17:15:48Z
helmreleases.helm.toolkit.fluxcd.io                    2022-04-06T17:15:48Z
helmrepositories.source.toolkit.fluxcd.io              2022-04-06T17:15:48Z
imagepolicies.image.toolkit.fluxcd.io                  2022-04-06T17:15:48Z
imagerepositories.image.toolkit.fluxcd.io              2022-04-06T17:15:48Z
imageupdateautomations.image.toolkit.fluxcd.io         2022-04-06T17:15:48Z
kustomizations.kustomize.toolkit.fluxcd.io             2022-04-06T17:15:48Z
providers.notification.toolkit.fluxcd.io               2022-04-06T17:15:48Z
receivers.notification.toolkit.fluxcd.io               2022-04-06T17:15:48Z
volumesnapshotclasses.snapshot.storage.k8s.io          2022-03-28T21:06:12Z
volumesnapshotcontents.snapshot.storage.k8s.io         2022-03-28T21:06:12Z
volumesnapshots.snapshot.storage.k8s.io                2022-03-28T21:06:12Z
websites.extensions.example.com                        2022-03-30T23:42:32Z

Confirm other details of the configuration by using the following commands.

kubectl get fluxconfigs -A

NAMESPACE        NAME             SCOPE     URL                                                       PROVISION   AGE
cluster-config   cluster-config   cluster   https://github.com/Azure/gitops-flux2-kustomize-helm-mt   Succeeded   44m

kubectl get gitrepositories -A

NAMESPACE        NAME             URL                                                       READY   STATUS                                                            AGE
cluster-config   cluster-config   https://github.com/Azure/gitops-flux2-kustomize-helm-mt   True    Fetched revision: main/4f1bdad4d0a54b939a5e3d52c51464f67e474fcf   45m

kubectl get helmreleases -A

NAMESPACE        NAME      READY   STATUS                             AGE
cluster-config   nginx     True    Release reconciliation succeeded   66m
cluster-config   podinfo   True    Release reconciliation succeeded   66m
cluster-config   redis     True    Release reconciliation succeeded   66m

kubectl get kustomizations -A


NAMESPACE        NAME                   READY   STATUS                                                            AGE
cluster-config   cluster-config-apps    True    Applied revision: main/4f1bdad4d0a54b939a5e3d52c51464f67e474fcf   65m
cluster-config   cluster-config-infra   True    Applied revision: main/4f1bdad4d0a54b939a5e3d52c51464f67e474fcf   65m

Workloads are deployed from manifests in the Git repository.

kubectl get deploy -n nginx

NAME                                       READY   UP-TO-DATE   AVAILABLE   AGE
nginx-ingress-controller                   1/1     1            1           67m
nginx-ingress-controller-default-backend   1/1     1            1           67m

kubectl get deploy -n podinfo

NAME      READY   UP-TO-DATE   AVAILABLE   AGE
podinfo   1/1     1            1           68m

kubectl get all -n redis

NAME                 READY   STATUS    RESTARTS   AGE
pod/redis-master-0   1/1     Running   0          68m

NAME                     TYPE        CLUSTER-IP    EXTERNAL-IP   PORT(S)    AGE
service/redis-headless   ClusterIP   None          <none>        6379/TCP   68m
service/redis-master     ClusterIP   10.0.13.182   <none>        6379/TCP   68m

NAME                            READY   AGE
statefulset.apps/redis-master   1/1     68m

Control which controllers are deployed with the Flux cluster extension

For some scenarios, you may wish to change which Flux controllers are installed with the Flux cluster extension.

The source, helm, kustomize, and notification Flux controllers are installed by default. The image-automation and image-reflector controllers, used to update a Git repository when new container images are available, must be enabled explicitly.

You can use the k8s-extension command to change the default options:

  • --config source-controller.enabled=<true/false> (default true)
  • --config helm-controller.enabled=<true/false> (default true)
  • --config kustomize-controller.enabled=<true/false> (default true)
  • --config notification-controller.enabled=<true/false> (default true)
  • --config image-automation-controller.enabled=<true/false> (default false)
  • --config image-reflector-controller.enabled=<true/false> (default false)

For instance, to disable notifications, you can set notification-controller.enabled to false.

This example command installs the image-reflector and image-automation controllers. If the Flux extension was created automatically when a Flux configuration was first created, the extension name will be flux.

az k8s-extension create -g <cluster_resource_group> -c <cluster_name> -t <connectedClusters or managedClusters or provisionedClusters> --name flux --extension-type microsoft.flux --config image-automation-controller.enabled=true image-reflector-controller.enabled=true

Using Kubelet identity as authentication method for AKS clusters

For AKS clusters, one of the authentication options to use is kubelet identity. By default, AKS creates its own kubelet identity in the managed resource group. If you prefer, you can use a pre-created kubelet managed identity. To do so, add the parameter --config useKubeletIdentity=true at the time of Flux extension installation.

az k8s-extension create --resource-group <resource-group> --cluster-name <cluster-name> --cluster-type managedClusters --name flux --extension-type microsoft.flux --config useKubeletIdentity=true

Red Hat OpenShift onboarding guidance

Flux controllers require a nonroot Security Context Constraint to properly provision pods on the cluster. These constraints must be added to the cluster prior to onboarding of the microsoft.flux extension.

NS="flux-system"
oc adm policy add-scc-to-user nonroot system:serviceaccount:$NS:kustomize-controller
oc adm policy add-scc-to-user nonroot system:serviceaccount:$NS:helm-controller
oc adm policy add-scc-to-user nonroot system:serviceaccount:$NS:source-controller
oc adm policy add-scc-to-user nonroot system:serviceaccount:$NS:notification-controller
oc adm policy add-scc-to-user nonroot system:serviceaccount:$NS:image-automation-controller
oc adm policy add-scc-to-user nonroot system:serviceaccount:$NS:image-reflector-controller

For more information on OpenShift guidance for onboarding Flux, see the Flux documentation.

Work with parameters

Flux supports many parameters to enable various scenarios. For a description of all parameters that Flux supports, see the official Flux documentation. Flux in Azure doesn't support all parameters yet. Let us know if a parameter you need is missing from the Azure implementation.

For more information about available parameters and how to use them, see GitOps Flux v2 configurations with AKS and Azure Arc-enabled Kubernetes. A workaround to deploy Flux resources with non-supported parameters is to define the required Flux custom resources inside your git repository. For example, GitRepository, Kustomization, etcetera. Then deploy these resources with the az k8s-configuration flux create command. You will then still be able to access your Flux resources through the Azure Arc UI.

Manage cluster configuration by using the Flux Kustomize controller

The Flux Kustomize controller is installed as part of the microsoft.flux cluster extension. It allows the declarative management of cluster configuration and application deployment by using Kubernetes manifests synced from a Git repository. These Kubernetes manifests can optionally include a kustomize.yaml file.

For usage details, see the following resources:

Manage Helm chart releases by using the Flux Helm controller

The Flux Helm controller is installed as part of the microsoft.flux cluster extension. It allows you to declaratively manage Helm chart releases with Kubernetes manifests that you maintain in your Git repository.

For usage details, see the following resources:

Tip

Because of how Helm handles index files, processing Helm charts is an expensive operation and can have very high memory footprint. As a result, reconciling a large number of Helm charts at once can cause memory spikes and OOMKilled errors. By default, the controller sets its memory limit at 1Gi and its memory requests at 64Mi. To increase this limit and requests due to a high number of large Helm chart reconciliations, run the following command after installing the microsoft.flux extension:

az k8s-extension update -g <resource-group> -c <cluster-name> -n flux -t connectedClusters --config source-controller.resources.limits.memory=2Gi source-controller.resources.requests.memory=300Mi

Use the GitRepository source for Helm charts

If your Helm charts are stored in the GitRepository source that you configure as part of the fluxConfigurations resource, you can indicate that the configured source should be used as the source of the Helm charts by adding clusterconfig.azure.com/use-managed-source: "true" to your HelmRelease.yaml file, as shown in the following example:

---
apiVersion: helm.toolkit.fluxcd.io/v2beta1
kind: HelmRelease
metadata:
  name: somename
  namespace: somenamespace
  annotations:
    clusterconfig.azure.com/use-managed-source: "true"
spec:
  ...

When you use this annotation, the deployed HelmRelease is patched with the reference to the configured source. Currently, only GitRepository source is supported.

Helm drift detection

Drift detection for Helm releases isn't enabled by default. Starting with microsoft.flux v1.7.5, you can enable Helm drift detection by running the following command:

az k8s-extension update --resource-group <resource-group> --cluster-name <cluster-name> --name flux --cluster-type <cluster-type> --config helm-controller.detectDrift=true

Helm OOM watch

Starting with microsoft.flux v1.7.5, you can enable Helm OOM watch. For more information, see Enable Helm near OOM detection.

Be sure to review potential remediation strategies and apply them as needed when enabling this feature.

To enable OOM watch, run the following command:

az k8s-extension update --resource-group <resource-group> --cluster-name <cluster-name> --name flux --cluster-type <cluster-type> --config helm-controller.outOfMemoryWatch.enabled=true helm-controller.outOfMemoryWatch.memoryThreshold=70 helm-controller.outOfMemoryWatch.interval=700ms

If you don't specify values for memoryThreshold and outOfMemoryWatch, the default memory threshold is set to 95%, with the interval at which to check the memory utilization set to 500 ms.

Delete the Flux configuration and extension

Use the following commands to delete your Flux configuration and, if desired, the Flux extension itself.

Delete the Flux configuration

The following command deletes both the fluxConfigurations resource in Azure and the Flux configuration objects in the cluster. Because the Flux configuration was originally created with the prune=true parameter for the kustomization, all of the objects created in the cluster based on manifests in the Git repository will be removed when the Flux configuration is removed. However, this command doesn't remove the Flux extension itself.

az k8s-configuration flux delete -g flux-demo-rg -c flux-demo-arc -n cluster-config -t connectedClusters --yes

Delete the Flux cluster extension

When you delete the Flux extension, both the microsoft.flux extension resource in Azure and the Flux extension objects in the cluster will be removed.

If the Flux extension was created automatically when the Flux configuration was first created, the extension name will be flux.

az k8s-extension delete -g flux-demo-rg -c flux-demo-arc -n flux -t connectedClusters --yes

Tip

These commands use -t connectedClusters, which is appropriate for an Azure Arc-enabled Kubernetes cluster. For an AKS cluster, use -t managedClusters instead. For AKS hybrid clusters provisioned from Azure, use -t provisionedClusters.

Next steps