Flagger Install on Kubernetes

This guide walks you through setting up Flagger on a Kubernetes cluster with Helm v3 or Kustomize.

Prerequisites

Flagger requires a Kubernetes cluster v1.14 or newer.

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/weaveworks/flagger/master/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 istio.kubeconfig.secretName=istio-kubeconfig \
--set istio.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

Deploy Flagger for App Mesh:

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

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

For ingress controllers, the install instructions are:

Enable Slack notifications:

helm upgrade -i flagger flagger/flagger \
--namespace=istio-system \
--set crd.create=false \
--set slack.url=https://hooks.slack.com/services/YOUR/SLACK/WEBHOOK \
--set slack.channel=general \
--set slack.user=flagger

Enable Microsoft Teams notifications:

helm upgrade -i flagger flagger/flagger \
--namespace=istio-system \
--set crd.create=false \
--set msteams.url=https://outlook.office.com/webhook/YOUR/TEAMS/WEBHOOK

You can use the helm template command and apply the generated yaml with kubectl:

# generate
helm fetch --untar --untardir . flagger/flagger &&
helm template flagger ./flagger \
--namespace=istio-system \
--set metricsServer=http://prometheus.istio-system:9090 \
> flagger.yaml
# apply
kubectl apply -f flagger.yaml

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 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

Or use helm template command and apply the generated yaml with kubectl:

# generate
helm fetch --untar --untardir . flagger/grafana &&
helm template flagger-grafana ./grafana \
--namespace=istio-system \
> flagger-grafana.yaml
# apply
kubectl apply -f flagger-grafana.yaml

You can access Grafana using port forwarding:

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

Install Flagger with Kustomize

As an alternative to Helm, Flagger can be installed with Kustomize 3.5.0 or newer.

Service mesh specific installers

Install Flagger for Istio:

kustomize build github.com/weaveworks/flagger//kustomize/istio | kubectl apply -f -

Install Flagger for AWS App Mesh:

kustomize build github.com/weaveworks/flagger//kustomize/appmesh | kubectl apply -f -

This deploys Flagger and sets the metrics server URL to App Mesh's Prometheus instance.

Install Flagger for Linkerd:

kustomize build github.com/weaveworks/flagger//kustomize/linkerd | kubectl apply -f -

This deploys Flagger in the linkerd namespace and sets the metrics server URL to Linkerd's Prometheus instance.

If you want to install a specific Flagger release, add the version number to the URL:

kustomize build github.com/weaveworks/flagger//kustomize/linkerd?ref=0.18.0 | kubectl apply -f -

Generic installer

Install Flagger and Prometheus for Contour, Gloo or NGINX ingress:

kustomize build github.com/weaveworks/flagger//kustomize/kubernetes | kubectl apply -f -

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.

To target a different provider you can specify it in the canary custom resource:

apiVersion: flagger.app/v1beta1
kind: Canary
metadata:
name: app
namespace: test
spec:
# can be: kubernetes, istio, linkerd, appmesh, nginx, gloo
# use the kubernetes provider for Blue/Green style deployments
provider: nginx

Customized installer

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

cat > kustomization.yaml <<EOF
namespace: istio-system
bases:
- github.com/weaveworks/flagger/kustomize/base/flagger
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
- -slack-user=flagger
- -slack-channel=alerts
- -slack-url=https://hooks.slack.com/services/YOUR/SLACK/WEBHOOK
EOF

Install Flagger for Istio with Slack notifications:

kustomize build . | kubectl apply -f -

If you want to use MS Teams instead of Slack, replace -slack-url with -msteams-url and set the webhook address to https://outlook.office.com/webhook/YOUR/TEAMS/WEBHOOK.