Configure IPv4-only clusters

What you’ll accomplish

After completing this guide, you will have disabled IPv6 in Istio’s ztunnel and CNI components and the Loki gateway so they can run on a cluster where IPv6 is unavailable.

Prerequisites

UDS CLI installed
Access to a Kubernetes cluster with IPv4 networking

Before you begin

These overrides affect only the listed components. They do not change your cluster’s Pod or Service IP families. Preserve any existing overrides for these components when you add the values below.

Steps

Add the IPv4-only overrides

Add these values under the core package in your uds-bundle.yaml:

packages:
  - name: core
    overrides:
      istio-controlplane:
        ztunnel:
          values:
            - path: meshConfig.defaultConfig.proxyMetadata
              value:
                IPV6_ENABLED: "false"
        cni:
          values:
            - path: ambient.ipv6
              value: false
      loki:
        loki:
          values:
            - path: gateway.nginxConfig.enableIPv6
              value: false

Create and deploy your bundle

Run these commands from the directory containing uds-bundle.yaml:
Terminal window
```
uds create --confirm && uds deploy uds-bundle-*.tar.zst --confirm
```

Verification

Check that the Istio daemonsets are ready and Loki pods are running:

uds zarf tools kubectl get daemonset ztunnel istio-cni-node -n istio-system
uds zarf tools kubectl get pods -n loki

The Istio DaemonSets should show all desired pods as ready, and the Loki gateway pod should show Running. If a component fails to start, inspect its pod logs before changing other networking settings.

Istio ztunnel troubleshooting - Understand the IPV6_ENABLED setting.