Bring your own instance of Prometheus, setting the namespace to match the managed OSM controller namespace
Enable permissive traffic policy after installation by updating the OSM MeshConfig resource:
# Replace <osm-namespace> with OSM controller's namespacekubectlpatchmeshconfigosm-mesh-config-n<osm-namespace>-p'{"spec":{"traffic":{"enablePermissiveTrafficPolicyMode":true}}}'--type=merge
To install Flagger in the default osm-system namespace, use:
Alternatively, if a non-default namespace or managed instance of OSM is in use, install Flagger with Helm, replacing the values as appropriate. If a custom instance of Prometheus is being used, replace osm-prometheus with the relevant Prometheus service name.
Flagger takes a Kubernetes deployment and optionally a horizontal pod autoscaler (HPA), then creates a series of objects (Kubernetes deployments, ClusterIP services and SMI traffic split). These objects expose the application inside the mesh and drive the canary analysis and promotion.
Create a test namespace and enable OSM namespace monitoring and metrics scraping for the namespace.
Create a canary custom resource for the podinfo deployment. The following podinfo canary custom resource instructs Flagger to:
monitor any changes to the podinfo deployment created earlier,
detect podinfo deployment revision changes, and
start a Flagger canary analysis, rollout, and promotion if there were deployment revision changes.
apiVersion:flagger.app/v1beta1kind:Canarymetadata:name:podinfonamespace:testspec:provider:osm# deployment referencetargetRef:apiVersion:apps/v1kind:Deploymentname:podinfo# HPA reference (optional)autoscalerRef:apiVersion:autoscaling/v2kind:HorizontalPodAutoscalername:podinfo# the maximum time in seconds for the canary deployment# to make progress before it is rolled back (default 600s)progressDeadlineSeconds:60service:# ClusterIP port numberport:9898# container port number or name (optional)targetPort:9898analysis:# schedule interval (default 60s)interval:30s# max number of failed metric checks before rollbackthreshold:5# max traffic percentage routed to canary# percentage (0-100)maxWeight:50# canary increment step# percentage (0-100)stepWeight:5# OSM Prometheus checksmetrics: - name:request-success-rate# minimum req success rate (non 5xx responses)# percentage (0-100)thresholdRange:min:99interval:1m - name:request-duration# maximum req duration P99# millisecondsthresholdRange:max:500interval:30s# testing (optional)webhooks: - name:acceptance-testtype:pre-rollouturl:http://flagger-loadtester.test/timeout:30smetadata:type:bashcmd:"curl -sd 'test' http://podinfo-canary.test:9898/token | grep token" - name:load-testtype:rollouturl:http://flagger-loadtester.test/timeout:5smetadata:cmd:"hey -z 2m -q 10 -c 2 http://podinfo-canary.test:9898/"
Save the above resource as podinfo-canary.yaml and then apply it:
kubectlapply-f./podinfo-canary.yaml
When the canary analysis starts, Flagger will call the pre-rollout webhooks before routing traffic to the canary. The canary analysis will run for five minutes while validating the HTTP metrics and rollout hooks every half a minute.
After a couple of seconds Flagger will create the canary objects.
After the bootstrap, the podinfo deployment will be scaled to zero and the traffic to podinfo.test will be routed to the primary pods. During the canary analysis, the podinfo-canary.test address can be used to target directly the canary pods.
Automated Canary Promotion
Flagger implements a control loop that gradually shifts traffic to the canary while measuring key performance indicators like HTTP requests success rate, requests average duration and pod health. Based on analysis of the KPIs a canary is promoted or aborted.
Trigger a canary deployment by updating the container image:
When the number of failed checks reaches the canary analysis thresholds defined in the podinfo canary custom resource earlier, the traffic is routed back to the primary, the canary is scaled to zero and the rollout is marked as failed.
kubectl -n test describe canary/podinfo
Status:
Canary Weight: 0
Failed Checks: 10
Phase: Failed
Events:
Starting canary analysis for podinfo.test
Pre-rollout check acceptance-test passed
Advance podinfo.test canary weight 5
Advance podinfo.test canary weight 10
Advance podinfo.test canary weight 15
Halt podinfo.test advancement success rate 69.17% < 99%
Halt podinfo.test advancement success rate 61.39% < 99%
Halt podinfo.test advancement success rate 55.06% < 99%
Halt podinfo.test advancement request duration 1.20s > 0.5s
Halt podinfo.test advancement request duration 1.45s > 0.5s
Rolling back podinfo.test failed checks threshold reached 5
Canary failed! Scaling down podinfo.test
Custom Metrics
The canary analysis can be extended with Prometheus queries.
Let's define a check for 404 not found errors. Edit the canary analysis (podinfo-canary.yaml file) and add the following metric. For more information on creating additional custom metrics using OSM metrics, please check the metrics available in OSM.
The above configuration validates the canary version by checking if the HTTP 404 req/sec percentage is below three percent of the total traffic. If the 404s rate reaches the 3% threshold, then the analysis is aborted and the canary is marked as failed.
Trigger a canary deployment by updating the container image:
