gRPC health probes are natively supported in beta since Kubernetes 1.24+. Before that we needed to add the grpc_health_probe binary in each Dockerfile.

Since the recent v0.4.1 version, the Online Boutique sample provides an option to have its applications supporting this feature. This allows to leverage the native Kubernetes feature, decrease the size of the container images by 4MB (virtual) and 11MB (on disk) as well as reduce the maintenance and surface of attack that this grpc_health_probe binary was adding.

What are the differences with before?

In your Dockerfile, you don’t need anymore to add the grpc_health_probe binary (like we needed to previously):

    wget -qO/bin/grpc_health_probe${GRPC_HEALTH_PROBE_VERSION}/grpc_health_probe-linux-amd64 && \
    chmod +x /bin/grpc_health_probe

In the Kubernetes manifests for your Deployments, here is the associated updates for both the readinessProbe and the livenessProbe:

+           grpc:
+             port: 9555
-           exec:
-             command:
-             - /bin/grpc_health_probe
-             - -addr=:9555

How to deploy the Online Boutique sample with this new feature?

Create a GKE cluster in version 1.24+:

gcloud container clusters create tests \
    --zone=us-east4-a \
    --machine-type=e2-standard-2 \
    --num-nodes=4 \

Note: as of now, the default version of GKE in rapid channel is 1.24.

From there, let’s deploy the Online Boutique sample with the gRPC health probes experimental variation.

Get the remote Kustomize components:

mkdir native-grpc-health-check
curl -L > native-grpc-health-check/kustomization.yaml

Update the local Kustomize components:

ONLINE_BOUTIQUE_VERSION=$(curl -s | jq -r '[.[]] | .[0].tag_name')
sed -i "s/ONLINE_BOUTIQUE_VERSION/$ONLINE_BOUTIQUE_VERSION/g" native-grpc-health-check/kustomization.yaml

Configure the Kustomize overlay:

cat <<EOF> kustomization.yaml
kind: Kustomization
- native-grpc-health-check

Optionally, you can render the Kubernetes manifests:

kustomize build .

In the Kubernetes manifests for the Deployments, here is the associated update for the container image:

-         image:*service:v0.4.1
+         image:*service:v0.4.1-native-grpc-probes

Deploy this Kustomize overlay:

kubectl apply -k .

If you wait a little bit, when all the Pods are running, you should have your Online Boutique website working successfully.

That’s how easy we were able to leverage the new native gRPC health probes with Kubernetes 1.24+ with the Online Boutique sample.

The Online Boutique sample apps are not yet supporting by default this native gRPC health probes, because Kubernetes 1.24+ is not widely nor commonly used yet. That’s why we need to use the optional associated Kustomize overlay.

Hope you enjoyed that one, happy sailing, cheers!