# App Mesh Canary Deployments This guide shows you how to use App Mesh and Flagger to automate canary deployments. You'll need an EKS cluster configured with App Mesh, you can find the install guide [here](https://docs.flagger.app/install/flagger-install-on-eks-appmesh). ### Bootstrap Flagger takes a Kubernetes deployment and optionally a horizontal pod autoscaler (HPA), then creates a series of objects (Kubernetes deployments, ClusterIP services, App Mesh virtual nodes and services). These objects expose the application on the mesh and drive the canary analysis and promotion. The only App Mesh object you need to create by yourself is the mesh resource. Create a mesh called `global`: ```bash export REPO=https://raw.githubusercontent.com/weaveworks/flagger/master kubectl apply -f ${REPO}/artifacts/appmesh/global-mesh.yaml ``` Create a test namespace with App Mesh sidecar injection enabled: ```bash kubectl apply -f ${REPO}/artifacts/namespaces/test.yaml ``` Create a deployment and a horizontal pod autoscaler: ```bash kubectl apply -f ${REPO}/artifacts/appmesh/deployment.yaml kubectl apply -f ${REPO}/artifacts/appmesh/hpa.yaml ``` Deploy the load testing service to generate traffic during the canary analysis: ```bash helm upgrade -i flagger-loadtester flagger/loadtester \ --namespace=test \ --set meshName=global.appmesh-system \ --set "backends[0]=podinfo.test" ``` Create a canary custom resource: ```yaml apiVersion: flagger.app/v1alpha3 kind: Canary metadata: name: podinfo namespace: test spec: # deployment reference targetRef: apiVersion: apps/v1 kind: Deployment name: podinfo # the maximum time in seconds for the canary deployment # to make progress before it is rollback (default 600s) progressDeadlineSeconds: 60 # HPA reference (optional) autoscalerRef: apiVersion: autoscaling/v2beta1 kind: HorizontalPodAutoscaler name: podinfo service: # container port port: 9898 # App Mesh reference meshName: global.appmesh-system # App Mesh egress (optional) backends: - backend.test # define the canary analysis timing and KPIs canaryAnalysis: # schedule interval (default 60s) interval: 10s # max number of failed metric checks before rollback threshold: 10 # max traffic percentage routed to canary # percentage (0-100) maxWeight: 50 # canary increment step # percentage (0-100) stepWeight: 5 # App Mesh Prometheus checks metrics: - name: request-success-rate # minimum req success rate (non 5xx responses) # percentage (0-100) threshold: 99 interval: 1m # external checks (optional) webhooks: - name: load-test url: http://flagger-loadtester.test/ timeout: 5s metadata: cmd: "hey -z 1m -q 10 -c 2 http://podinfo.test:9898/" ``` Save the above resource as podinfo-canary.yaml and then apply it: ```bash kubectl apply -f ./podinfo-canary.yaml ``` After a couple of seconds Flagger will create the canary objects: ```bash # applied deployment.apps/podinfo horizontalpodautoscaler.autoscaling/podinfo canary.flagger.app/podinfo # generated Kubernetes objects deployment.apps/podinfo-primary horizontalpodautoscaler.autoscaling/podinfo-primary service/podinfo service/podinfo-canary service/podinfo-primary # generated App Mesh objects virtualnode.appmesh.k8s.aws/podinfo virtualnode.appmesh.k8s.aws/podinfo-canary virtualnode.appmesh.k8s.aws/podinfo-primary virtualservice.appmesh.k8s.aws/podinfo.test ``` The App Mesh specific settings are: ```yaml service: port: 9898 meshName: global.appmesh-system backends: - backend1.test - backend2.test ``` App Mesh blocks all egress traffic by default. If your application needs to call another service, you have to create an App Mesh virtual service for it and add the virtual service name to the backend list. ### Setup App Mesh ingress (optional) In order to expose the podinfo app outside the mesh you'll be using an Envoy ingress and an AWS classic load balancer. The ingress binds to an internet domain and forwards the calls into the mesh through the App Mesh sidecar. If podinfo becomes unavailable due to a HPA downscaling or a node restart, the ingress will retry the calls for a short period of time. Deploy the ingress and the AWS ELB service: ```bash kubectl apply -f ${REPO}/artifacts/appmesh/ingress.yaml ``` Find the ingress public address: ```bash kubectl -n test describe svc/ingress | grep Ingress LoadBalancer Ingress: yyy-xx.us-west-2.elb.amazonaws.com ``` Wait for the ELB to become active: ```bash watch curl -sS ${INGRESS_URL} ``` Open your browser and navigate to the ingress address to access podinfo UI. ### Automated canary promotion Trigger a canary deployment by updating the container image: ```bash kubectl -n test set image deployment/podinfo \ podinfod=quay.io/stefanprodan/podinfo:1.4.1 ``` Flagger detects that the deployment revision changed and starts a new rollout: ```text kubectl -n test describe canary/podinfo Status: Canary Weight: 0 Failed Checks: 0 Phase: Succeeded Events: Type Reason Age From Message ---- ------ ---- ---- ------- Normal Synced 3m flagger New revision detected podinfo.test Normal Synced 3m flagger Scaling up podinfo.test Warning Synced 3m flagger Waiting for podinfo.test rollout to finish: 0 of 1 updated replicas are available Normal Synced 3m flagger Advance podinfo.test canary weight 5 Normal Synced 3m flagger Advance podinfo.test canary weight 10 Normal Synced 3m flagger Advance podinfo.test canary weight 15 Normal Synced 2m flagger Advance podinfo.test canary weight 20 Normal Synced 2m flagger Advance podinfo.test canary weight 25 Normal Synced 1m flagger Advance podinfo.test canary weight 30 Normal Synced 1m flagger Advance podinfo.test canary weight 35 Normal Synced 55s flagger Advance podinfo.test canary weight 40 Normal Synced 45s flagger Advance podinfo.test canary weight 45 Normal Synced 35s flagger Advance podinfo.test canary weight 50 Normal Synced 25s flagger Copying podinfo.test template spec to podinfo-primary.test Warning Synced 15s flagger Waiting for podinfo-primary.test rollout to finish: 1 of 2 updated replicas are available Normal Synced 5s flagger Promotion completed! Scaling down podinfo.test ``` **Note** that if you apply new changes to the deployment during the canary analysis, Flagger will restart the analysis. During the analysis the canary’s progress can be monitored with Grafana. The App Mesh dashboard URL is http://localhost:3000/d/flagger-appmesh/appmesh-canary?refresh=10s&orgId=1&var-namespace=test&var-primary=podinfo-primary&var-canary=podinfo ![App Mesh Canary Dashboard](https://raw.githubusercontent.com/weaveworks/flagger/master/docs/screens/flagger-grafana-appmesh.png) You can monitor all canaries with: ```bash watch kubectl get canaries --all-namespaces NAMESPACE NAME STATUS WEIGHT LASTTRANSITIONTIME test podinfo Progressing 15 2019-03-16T14:05:07Z prod frontend Succeeded 0 2019-03-15T16:15:07Z prod backend Failed 0 2019-03-14T17:05:07Z ``` If you’ve enabled the Slack notifications, you should receive the following messages: ![Flagger Slack Notifications](https://raw.githubusercontent.com/weaveworks/flagger/master/docs/screens/slack-canary-notifications.png) ### Automated rollback During the canary analysis you can generate HTTP 500 errors to test if Flagger pauses the rollout. Trigger a canary deployment: ```bash kubectl -n test set image deployment/podinfo \ podinfod=quay.io/stefanprodan/podinfo:1.4.2 ``` Exec into the load tester pod with: ```bash kubectl -n test exec -it flagger-loadtester-xx-xx sh ``` Generate HTTP 500 errors: ```bash hey -z 1m -c 5 -q 5 http://podinfo.test:9898/status/500 ``` When the number of failed checks reaches the canary analysis threshold, the traffic is routed back to the primary, the canary is scaled to zero and the rollout is marked as failed. ```text kubectl -n test describe canary/podinfo Status: Canary Weight: 0 Failed Checks: 10 Phase: Failed Events: Type Reason Age From Message ---- ------ ---- ---- ------- Normal Synced 3m flagger Starting canary deployment for podinfo.test Normal Synced 3m flagger Advance podinfo.test canary weight 5 Normal Synced 3m flagger Advance podinfo.test canary weight 10 Normal Synced 3m flagger Advance podinfo.test canary weight 15 Normal Synced 3m flagger Halt podinfo.test advancement success rate 69.17% < 99% Normal Synced 2m flagger Halt podinfo.test advancement success rate 61.39% < 99% Normal Synced 2m flagger Halt podinfo.test advancement success rate 55.06% < 99% Normal Synced 2m flagger Halt podinfo.test advancement success rate 47.00% < 99% Normal Synced 2m flagger (combined from similar events): Halt podinfo.test advancement success rate 38.08% < 99% Warning Synced 1m flagger Rolling back podinfo.test failed checks threshold reached 10 Warning Synced 1m flagger Canary failed! Scaling down podinfo.test ``` If you’ve enabled the Slack notifications, you’ll receive a message if the progress deadline is exceeded, or if the analysis reached the maximum number of failed checks: ![Flagger Slack Notifications](https://raw.githubusercontent.com/weaveworks/flagger/master/docs/screens/slack-canary-failed.png)