Canary Deployments to GKE and GKE Enterprise using Gateway API networking

This document describes how to configure and use canary deployments to deploy your applications to GKE or GKE Enterprise using Cloud Deploy with Kubernetes Gateway API service mesh.

A canary deployment is a progressive rollout of a new version of your application, where you gradually increase the percentage of traffic sent to the new version, while monitoring the application's performance. This helps you to catch potential problems early and minimize the impact on your users.

How canary deployments work for GKE and GKE Enterprise using Gateway API

In addition to the Deployment and Service references, you provide an HTTPRoute resource, with a backendRefs rule that references the Service.
Cloud Deploy creates a new Deployment, with the name of your original Deployment plus -canary, and a new Service with the original Service name plus -canary.

Secrets, ConfigMaps, and Horizontal Pod Autoscalers are also copied and renamed with -canary.
For each canary phase Cloud Deploy modifies the HTTPRoute to update the weighting between the original Deployment's pods and the canary Deployment's pods, based on the percentage for that phase.

Because there can be a delay propagating changes to HTTPRoute resources, you can include the routeUpdateWaitTime property in your configuration, so the system waits a specified amount of time for this propagation.
During the stable phase, the -canary Deployment is scaled down to zero, and the original Deployment is updated to use the new release's Deployment.

Also, the HTTPRoute is now reverted to the original which you supplied.

Cloud Deploy doesn't modify the original Deployment or Service until the stable phase.

Using Cloud Deploy, you can configure canary deployments to GKE and GKE Enterprise in a single stage or in multiple stages.

The instructions here include only what is specific to canary configuration. The document Deploy to a Google Kubernetes Engine cluster has the general instructions for configuring and executing your deployment pipeline.

Make sure you have the required permissions

In addition to other Identity and Access Management permissions you need for using Cloud Deploy, you need the following permissions in order to perform additional actions that might be needed for a canary deployment:

clouddeploy.rollouts.advance
clouddeploy.rollouts.ignoreJob
clouddeploy.rollouts.cancel
clouddeploy.rollouts.retryJob
clouddeploy.jobRuns.get
clouddeploy.jobRuns.list
clouddeploy.jobRuns.terminate

See IAM roles and permissions for more information about what available roles include these permissions.

Prepare your `skaffold.yaml`

Your skaffold.yaml file defines how your Kubernetes manifests are rendered and deployed. For a canary deployment to GKE/GKE Enterprise, ensure it correctly points to your manifests and defines any necessary build artifacts. No special canary-specific configuration is required within skaffold.yaml itself beyond what's needed for a standard deployment. You might use Skaffold profiles to manage different manifest variations for custom canary phases.

Prepare your Kubernetes manifests

Your Kubernetes manifests must include both a Deployment resource and a Service resource. The Service must define a selector that matches the labels of the pods managed by the Deployment. The default label Cloud Deploy looks for is app, but this can be configured in the pipeline.

In addition to the Deployment and Service, your manifests must include an HTTPRoute resource configured for traffic splitting, referencing the Service and associated Gateway.

Configure an automated canary

Use Kubernetes Gateway API (with Istio or any supported implementation) for precise, percentage-based traffic splitting managed by the mesh/gateway, orchestrated by Cloud Deploy.

Set up Gateway API Resources: Ensure your Gateway, and underlying service mesh (e.g., Istio) or Gateway controller are correctly configured in your cluster(s).
- Using Istio
- GKE Gateway controller
In your Kubernetes manifest, provided to Cloud Deploy when you created the release, include the following:
- An HTTPRoute that references your Gateway resource
- A Deployment
- A Service
Configure your delivery pipeline and the target that you will canary-deploy to:
- Configuration for the target is the same as for any target.
- The delivery pipeline configuration, in the progression sequence for the specific target, includes a gatewayServiceMesh stanza to reference your Kubernetes Gateway API HTTPRoute configuration, as well as your Deployment and Service.
```
strategy:
 canary:
   runtimeConfig:
     kubernetes:
       gatewayServiceMesh:
         httpRoute: "ROUTE"
         service: "SERVICE"
         deployment: "DEPLOYMENT"
         routeUpdateWaitTime: "WAIT_TIME"
         podSelectorLabel: "LABEL"
   canaryDeployment:
     percentages:
     - 50
```
  Where...
  - ROUTE is your httpRoute configuration that defines the routing behavior you want.
  - SERVICE is your Service configuration, which Cloud Deploy requires for canary deployments to GKE and GKE Enterprise.
  - DEPLOYMENT is your Deployment configuration, which Cloud Deploy requires for canary deployments to GKE and GKE Enterprise.
  - WAIT_TIME is an amount of time for Cloud Deploy to wait for changes to the HTTPRoute resource to finish propagating, to avoid dropped requests. For example: routeUpdateWaitTime: 60s.
    
    If you're running canary using Gateway API without Istio, and the Gateway API is connected to a Google Cloud load balancer, a small amount of traffic may be lost when the canary instance is scaled down. You can configure this setting if you observe this behavior.
  - LABEL is a pod selector label. This must match the label selector in the Kubernetes Service and Deployment defined in your manifest. This is optional. The default is app.

Configure a custom-automated canary

This combines custom phase definition (names, percentages, profiles, verify, hooks) with Cloud Deploy's automatic traffic management for GKE or GKE Enterprise. You define the phases, but Cloud Deploy handles the underlying resource manipulation based on the percentages and the chosen runtimeConfig.

To configure this, include both a runtimeConfig section with serviceNetworking and the customCanaryDeployment section (defining phaseConfigs) within the strategy.canary block. Cloud Deploy will use the specified Skaffold profiles for rendering but will automatically adjust traffic according to the runtimeConfig and phase percentages.

serialPipeline:
  stages:
  - targetId: gke-prod
    profiles: []
    strategy:
      canary:
        # Include runtimeConfig for automatic traffic management
        runtimeConfig:
          kubernetes:
            gatewayServiceMesh:
              httpRoute: "my-route"
              service: "my-app"
              deployment: "my-deployment"  
        # Include customCanaryDeployment for phase customization
        customCanaryDeployment:
          phaseConfigs:
          - phaseId: "warmup"
            percentage: 10
            profiles: ["profile-a"] # Profile used for rendering this phase
            verify: true
          - phaseId: "scaling"
            percentage: 50
            profiles: ["profile-b"] # Different profile for this phase
            verify: true
          - phaseId: "stable"
            percentage: 100
            profiles: ["profile-b"] # Can reuse profiles
            verify: true

Deploy an HTTPRoute to a different cluster

When you have a canary configured using Gateway API service mesh, you can specify an alternate, non-target cluster on which to deploy the HTTPRoute.

To do so, you use a routeDestinations stanza, in your canary strategy configuration, to identify the destination cluster or clusters for the HTTPRoute, and a boolean setting to propagate the Service to the same non-target cluster. And you create an associatedEntities stanza in your target configuration to identify the clusters.

Configure associatedEntities on your target.

Each entity is a cluster where Cloud Deploy will deploy the HTTPRoute and, optionally, the Kubernetes Service. In your target definition, include an associatedEntities stanza:
```
associatedEntities:
  [KEY]:
    gkeClusters:
    - cluster: [PATH]
      dnsEndpoint: [true|false]
      internalIp: [true|false]
      proxyUrl:
```
Where:
- KEY is an arbitrary name for this group of associated entities. You'll use this name to reference the entities from the routeDestinations in your canary config.
- PATH is the resource path identifying the GKE cluster where your HTTPRoute (and optionally the Service) will be deployed.
- dnsEndpoint indicates whether or not to use the cluster's DNS Endpoint if multiple endpoints are configured. The default is false.
- internalIp indicates whether or not to use the cluster's internal IP (private IP) if multiple endpoints are configured. The default is false.
You can include any number of clusters, with or without internalIp.
Configure routeDestinations in your canary config.

Each route destination references an associatedEntities stanza, and indicates whether or not to also deploy the Service to the alternate cluster. Add the following inside gatewayServiceMesh stanza in your canary config:
```
routeDestinations:
  destinationIds: ["KEY"]
  propagateService: [true|false]
```
Where:
- KEY is the name you configured in the target, in associatedEntities. Use this name to reference the entities from the routeDestinations in your canary config.
  
  You can also provide the value @self to deploy the HTTPRoute to the target cluster in addition to the associated destination.
- propagateService indicates whether or not you want to deploy the Service to the associated cluster, in addition to the HTTPRoute. The default is false.

Execute the GKE or GKE Enterprise canary

Register Pipeline and Targets: Apply your delivery pipeline and GKE or GKE Enterprise target configuration files.
```
gcloud deploy apply --file=delivery-pipeline.yaml --region=REGION
gcloud deploy apply --file=gke-targets.yaml --region=REGION
```
The delivery pipeline includes the automated or custom canary configuration, for your chosen runtime.

Create a Release: Start the deployment, providing the image name.


gcloud deploy releases create RELEASE_NAME \
                                --delivery-pipeline=PIPELINE_NAME \
                                --region=REGION
  # e.g., --images=my-cloudrun-service=gcr.io/my-project/my-app:v1.1
  # Add --skaffold-file or --source if not using default Skaffold config discovery

The delivery pipeline identified by PIPELINE_NAME contains the automated or custom canary configuration described in this document.

Advance the canary:
gcloud CLI
```
gcloud deploy rollouts advance ROLLOUT_NAME \
                            --release=RELEASE_NAME \
                            --delivery-pipeline=PIPELINE_NAME \
                            --region=REGION
```
Where:

ROLLOUT_NAME is the name of the current rollout which you're advancing to the next phase.

RELEASE_NAME is the name of the release that this rollout is part of.

PIPELINE_NAME is the name of the delivery pipeline you're using to manage deployment of this release.

REGION is the name of the region in which the release was created, for example us-central1. This is required.

See the Google Cloud SDK reference for more information about the gcloud deploy rollouts advance command.
Google Cloud console
1. Open the Delivery pipelines page.
2. Click your pipeline shown in the list of delivery pipelines.
  
  The Delivery pipeline details page shows a graphical representation of your delivery pipeline's progress.
3. On the Rollouts tab, under Delivery pipeline details, click the name of your rollout.
  
  The rollout details page is shown, for that rollout.
  
  Notice that in this example, the rollout has a canary-50 phase and a stable phase. Your rollout might have more phases or different phases.
4. Click Advance rollout.
  
  The rollout is advanced to the next phase.

Skipped phases

If you deploy a canary and your application has not been deployed to that runtime yet, Cloud Deploy skips the canary phase and runs the stable phase. See Skipping phases the first time to find out why this happens.

What's next

Try the canary deployment quickstart.
Find out how to manage the lifecycle of your canary's rollouts.
Learn more about parallel deployment.
Learn more about Cloud Deploy deployment strategies.