Flagger Install on Kubernetes

This guide walks you through setting up Flagger on a Kubernetes cluster with Helm or Kubectl.

See the Flux install guide for installing Flagger and keeping it up to date the GitOps way.

Install Flagger with Helm

Add Flagger Helm repository:

helm repo add flagger https://flagger.app

Install Flagger's Canary CRD:

kubectl apply -f https://raw.githubusercontent.com/fluxcd/flagger/main/artifacts/flagger/crd.yaml

Deploy Flagger for Istio:

helm upgrade -i flagger flagger/flagger \
--namespace=istio-system \
--set crd.create=false \
--set meshProvider=istio \
--set metricsServer=http://prometheus:9090

Note that Flagger depends on Istio telemetry and Prometheus, if you're installing Istio with istioctl then you should be using the default profile.

For Istio multi-cluster shared control plane you can install Flagger on each remote cluster and set the Istio control plane host cluster kubeconfig:

helm upgrade -i flagger flagger/flagger \
--namespace=istio-system \
--set crd.create=false \
--set meshProvider=istio \
--set metricsServer=http://istio-cluster-prometheus:9090 \
--set controlplane.kubeconfig.secretName=istio-kubeconfig \
--set controlplane.kubeconfig.key=kubeconfig

Note that the Istio kubeconfig must be stored in a Kubernetes secret with a data key named kubeconfig. For more details on how to configure Istio multi-cluster credentials read the Istio docs.

Deploy Flagger for Linkerd:

helm upgrade -i flagger flagger/flagger \
--namespace=linkerd \
--set crd.create=false \
--set meshProvider=linkerd \
--set metricsServer=http://linkerd-prometheus:9090

If you need to add labels to the flagger deployment or pods, you can pass the labels as parameters as shown below.

helm upgrade -i flagger flagger/flagger \
<other parameters> \
--set podLabels.<labelName>=<labelValue> \
--set deploymentLabels.<labelName>=<labelValue> 

You can install Flagger in any namespace as long as it can talk to the Prometheus service on port 9090.

For ingress controllers, the installation instructions are:

• Contour

• Gloo

• NGINX

• Skipper

• Traefik

• APISIX

To uninstall the Flagger release with Helm run:

helm delete flagger

The command removes all the Kubernetes components associated with the chart and deletes the release.

Note that on uninstall the Canary CRD will not be removed. Deleting the CRD will make Kubernetes remove all the objects owned by Flagger like Istio virtual services, Kubernetes deployments and ClusterIP services.

If you want to remove all the objects created by Flagger you have to delete the Canary CRD with kubectl:

kubectl delete crd canaries.flagger.app

Install Grafana with Helm

Flagger comes with a Grafana dashboard made for monitoring the canary analysis.

Deploy Grafana in the istio-system namespace:

helm upgrade -i flagger-grafana flagger/grafana \
--namespace=istio-system \
--set url=http://prometheus.istio-system:9090 \
--set user=admin \
--set password=change-me

You can access Grafana using port forwarding:

kubectl -n istio-system port-forward svc/flagger-grafana 3000:80

Install Flagger with Kubectl

Install Flagger and Prometheus using the Kustomize overlay from the GitHub repository:

kubectl apply -k https://github.com/fluxcd/flagger/kustomize/kubernetes?ref=main

This deploys Flagger and Prometheus in the flagger-system namespace, sets the metrics server URL to http://flagger-prometheus.flagger-system:9090 and the mesh provider to kubernetes.

The Prometheus instance has a two hours data retention and is configured to scrape all pods in your cluster that have the prometheus.io/scrape: "true" annotation.

Customized installer

Create a kustomization file using Flagger as base and patch the container args:

cat > kustomization.yaml <<EOF
namespace: istio-system
bases:
  - https://github.com/fluxcd/flagger/kustomize/kubernetes?ref=main
patches:
- target:
    kind: Deployment
    name: flagger
  patch: |-
    apiVersion: apps/v1
    kind: Deployment
    metadata:
      name: flagger
    spec:
      template:
        spec:
          containers:
          - name: flagger
            args:
              - -mesh-provider=istio
              - -metrics-server=http://prometheus.istio-system:9090
              - -include-label-prefix=app.kubernetes.io
EOF