Cilium gateway and flagger integration

content/en/flagger/tutorials/cilium-progressive-delivery.md

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+---
+weight: 1
+title: Cilium Gateway API Canary Deployments
+---
+
+This guide shows you how to use Cilium's implementation of the [Gateway API](https://gateway-api.sigs.k8s.io/) and Flagger to automate canary deployments and A/B testing.
+
+![Flagger Canary Stages](/img/diagrams/flagger-canary-steps.png)
+
+## Prerequisites
+
+Flagger requires a Kubernetes cluster **v1.19** or newer and any mesh/ingress that implements the `v1beta1` version of Gateway API.
+
+Ensure that you have the Kubernetes Gateway API CRDs installed:
+```bash
+kubectl apply -f https://raw.githubusercontent.com/kubernetes-sigs/gateway-api/v0.7.0/config/crd/standard/gateway.networking.k8s.io_gatewayclasses.yaml
+kubectl apply -f https://raw.githubusercontent.com/kubernetes-sigs/gateway-api/v0.7.0/config/crd/standard/gateway.networking.k8s.io_gateways.yaml
+kubectl apply -f https://raw.githubusercontent.com/kubernetes-sigs/gateway-api/v0.7.0/config/crd/standard/gateway.networking.k8s.io_httproutes.yaml
+kubectl apply -f https://raw.githubusercontent.com/kubernetes-sigs/gateway-api/v0.7.0/config/crd/standard/gateway.networking.k8s.io_referencegrants.yaml
+kubectl apply -f https://raw.githubusercontent.com/kubernetes-sigs/gateway-api/v0.7.0/config/crd/experimental/gateway.networking.k8s.io_tlsroutes.yaml
+```
+
+Install Cilium with Gateway API enabled:
+```bash
+# To install with Helm
+helm install cilium cilium/cilium \
+    --namespace kube-system \
+    --set gatewayAPI.enabled=true \ 
+    --set kubeProxyReplacement=true 
+```
+This will also create a `GatewayClass` on your behalf. Try running `kubectl get gatewayclass -A` to verify it is there.
+
+Install Flagger in the `flagger-system` namespace:
+
+```bash
+kubectl apply -k github.com/fluxcd/flagger//kustomize/gatewayapi
+```
+## Creating the Gateway
+Create a `cilium` namespace:
+```bash
+kubectl create ns cilium
+```
+Create a `Gateway` that configures load balancing, traffic ACL, etc:
+```yaml
+kind: Gateway
+apiVersion: gateway.networking.k8s.io/v1beta1
+metadata:
+  name: cilium
+  namespace: cilium
+spec:
+  gatewayClassName: cilium
+  listeners:
+    - name: http
+      protocol: HTTP
+      port: 80
+      allowedRoutes:
+        namespaces:
+          from: All
+```
+
+----
+## Bootstrap
+
+Flagger takes a Kubernetes deployment and optionally a horizontal pod autoscaler \(HPA\), then creates a series of objects \(Kubernetes deployments, ClusterIP services, HTTPRoutes for the Gateway\). These objects expose the application inside the mesh and drive the canary analysis and promotion.
+
+Create a test namespace:
+
+```bash
+kubectl create ns test
+```
+
+Create a deployment and a horizontal pod autoscaler:
+
+```bash
+kubectl apply -k https://github.com/fluxcd/flagger//kustomize/podinfo?ref=main
+```
+
+Deploy the load testing service to generate traffic during the canary analysis:
+
+```bash
+kubectl apply -k https://github.com/fluxcd/flagger//kustomize/tester?ref=main
+```
+
+Create metric templates targeting the Prometheus server in the `flagger-system` namespace. This example will use the default metrics that Flagger provides. You can [change it to your ingress/mesh provider](/flagger/faq#metrics) accordingly.
+
+```yaml
+apiVersion: flagger.app/v1beta1
+kind: MetricTemplate
+metadata:
+  name: latency
+  namespace: flagger-system
+spec:
+  provider:
+    type: prometheus
+    address: http://flagger-prometheus:9090
+  query: |
+    histogram_quantile(0.99,
+      sum(
+        rate(
+          envoy_cluster_upstream_rq_time_bucket{
+            envoy_cluster_name=~"{{ namespace }}_{{ target }}-canary_[0-9a-zA-Z-]+",
+          }[{{ interval }}]
+        )
+      ) by (le)
+    )/1000
+---
+apiVersion: flagger.app/v1beta1
+kind: MetricTemplate
+metadata:
+  name: error-rate
+  namespace: flagger-system
+spec:
+  provider:
+    type: prometheus
+    address: http://flagger-prometheus:9090
+  query: |
+    100 - sum(
+      rate(
+        http_requests_total{
+          namespace="{{ namespace }}",
+          status!~"5.*"
+        }[{{ interval }}]
+      )
+    )
+    /
+    sum(
+      rate(
+        http_requests_total{
+          namespace="{{ namespace }}",
+        }[{{ interval }}]
+      )
+    )
+    * 100
+```
+
+Save the above resource as metric-templates.yaml and then apply it:
+
+```bash
+kubectl apply -f metric-templates.yaml
+```
+
+Create a canary custom resource \(replace "loaclproject.contour.io" with your own domain\):
+```yaml
+apiVersion: flagger.app/v1beta1
+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/v2
+    kind: HorizontalPodAutoscaler
+    name: podinfo
+  service:
+    # service port number
+    port: 9898
+    # container port number or name (optional)
+    targetPort: 9898
+    # Gateway API HTTPRoute host names
+    # Reference to the Gateway that the generated HTTPRoute would attach to.
+    gatewayRefs:
+      - name: cilium
+        namespace: cilium
+  analysis:
+    # schedule interval (default 60s)
+    interval: 1m
+    # max number of failed metric checks before rollback
+    threshold: 5
+    # max traffic percentage routed to canary
+    # percentage (0-100)
+    maxWeight: 50
+    # canary increment step
+    # percentage (0-100)
+    stepWeight: 10
+    metrics:
+    - name: request-success-rate
+      interval: 1m
+      # minimum req success rate (non 5xx responses)
+      # percentage (0-100)
+      thresholdRange:
+        min: 99
+    - name: error-rate
+      # max error rate (5xx responses)
+      # percentage (0-100)
+      templateRef:
+        name: error-rate
+        namespace: flagger-system
+      thresholdRange:
+        max: 1
+      interval: 1m
+    - name: latency
+      templateRef:
+        name: latency
+        namespace: flagger-system
+      # seconds
+      thresholdRange:
+         max: 0.5
+      interval: 30s
+```
+
+```bash
+# applied 
+deployment.apps/podinfo
+horizontalpodautoscaler.autoscaling/podinfo
+canary.flagger.app/podinfo
+
+# generated 
+deployment.apps/podinfo-primary
+horizontalpodautoscaler.autoscaling/podinfo-primary
+service/podinfo
+service/podinfo-canary
+service/podinfo-primary
+httproutes.gateway.networking.k8s.io/podinfo
+```
+
+## Automated canary promotion
+
+Trigger a canary deployment by updating the container image:
+
+```bash
+kubectl -n test set image deployment/podinfo \
+podinfod=ghcr.io/stefanprodan/podinfo:6.0.1
+```
+
+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.
+
+A canary deployment is triggered by changes in any of the following objects:
+
+* Deployment PodSpec \(container image, command, ports, env, resources, etc\)
+* ConfigMaps mounted as volumes or mapped to environment variables
+* Secrets mounted as volumes or mapped to environment variables
+
+You can monitor how Flagger progressively changes the weights of the HTTPRoute object that is attahed to the Gateway with:
+
+```bash
+watch kubectl get httproute -n test podinfo -o=jsonpath='{.spec.rules}'
+```
+
+You can monitor all canaries with:
+
+```bash
+watch kubectl get canaries --all-namespaces
+
+NAMESPACE   NAME      STATUS        WEIGHT   LASTTRANSITIONTIME
+test        podinfo   Progressing   15       2022-01-16T14:05:07Z
+prod        frontend  Succeeded     0        2022-01-15T16:15:07Z
+prod        backend   Failed        0        2022-01-14T17:05:07Z
+```
+
+
+## Automated rollback
+
+During the canary analysis you can generate HTTP 500 errors and high latency to test if Flagger pauses the rollout.
+
+Trigger another canary deployment:
+
+```bash
+kubectl -n test set image deployment/podinfo \
+podinfod=ghcr.io/stefanprodan/podinfo:6.0.2
+```
+
+Exec into the load tester pod with:
+
+```bash
+kubectl -n test exec -it flagger-loadtester-xx-xx sh
+```
+
+Generate HTTP 500 errors:
+
+```bash
+watch curl http://podinfo-canary:9898/status/500
+```
+
+Generate latency:
+
+```bash
+watch curl http://podinfo-canary:9898/delay/1
+```
+
+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
+```
+
+The above procedures can be extended with [custom metrics](../usage/metrics.md) checks, [webhooks](../usage/webhooks.md), [manual promotion](../usage/webhooks.md#manual-gating) approval and [Slack or MS Teams](../usage/alerting.md) notifications.