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This documentation is for an older version of Linkerd. You may want the Linkerd 2.12 (current) documentation instead.

Cluster Configuration


Private Clusters

If you are using a private GKE cluster, you are required to create a firewall rule that allows the GKE operated api-server to communicate with the Linkerd control plane. This makes it possible for features such as automatic proxy injection to receive requests directly from the api-server.

In this example, we will use gcloud to simplify the creation of the said firewall rule.



Set default zone for zonal clusters or the default region for regional clusters (see types of clusters

gcloud config set compute/zone your-zone
gcloud config set compute/region your-region

Get the cluster MASTER_IPV4_CIDR:

MASTER_IPV4_CIDR=$(gcloud container clusters describe $CLUSTER_NAME \
  | grep "masterIpv4CidrBlock: " \
  | awk '{print $2}')

Get the cluster NETWORK:

NETWORK=$(gcloud container clusters describe $CLUSTER_NAME \
  | grep "^network: " \
  | awk '{print $2}')

Get the cluster auto-generated NETWORK_TARGET_TAG:

NETWORK_TARGET_TAG=$(gcloud compute firewall-rules list \
  --filter network=$NETWORK --format json \
  | jq ".[] | select(.name | contains(\"$CLUSTER_NAME\"))" \
  | jq -r '.targetTags[0]' | head -1)

The format of the network tag should be something like gke-cluster-name-xxxx-node.

Verify the values:


# example output foo-network gke-foo-cluster-c1ecba83-node

Create the firewall rules for proxy-injector and tap:

gcloud compute firewall-rules create gke-to-linkerd-control-plane \
  --network "$NETWORK" \
  --allow "tcp:8443,tcp:8089" \
  --source-ranges "$MASTER_IPV4_CIDR" \
  --target-tags "$NETWORK_TARGET_TAG" \
  --priority 1000 \
  --description "Allow traffic on ports 8443, 8089 for linkerd control-plane components"

Finally, verify that the firewall is created:

gcloud compute firewall-rules describe gke-to-linkerd-control-plane