website/linkerd.io/content/2.12/tasks/using-custom-domain.md

title	description
Using a Custom Cluster Domain	Use Linkerd with a custom cluster domain.

For Kubernetes clusters that use custom cluster domain, Linkerd must be installed using the --cluster-domain option:

# first, install the Linkerd CRDs:
linkerd install --crds | kubectl apply -f -

# next, install the Linkerd control plane, using the custom cluster domain:
linkerd install --cluster-domain=example.org \
    --identity-trust-domain=example.org \
    | kubectl apply -f -

# The Linkerd Viz extension also requires a similar setting:
linkerd viz install --set clusterDomain=example.org | kubectl apply -f -

# And so does the Multicluster extension:
linkerd multicluster install --set identityTrustDomain=example.org | kubectl apply -f -

This ensures that all Linkerd handles all service discovery, routing, service profiles and traffic split resources using the example.org domain.

{{< note >}} Note that the identity trust domain must match the cluster domain for mTLS to work. {{< /note >}}

{{< note >}} Changing the cluster domain while upgrading Linkerd isn't supported. {{< /note >}}