kube-router

packaged by Chainguard

Chainguard Container for kube-router

A single-binary Kubernetes networking solution providing pod networking (CNI), an IPVS-based service proxy, and iptables/ipset network policy enforcement.

Chainguard Containers are regularly-updated, secure-by-default container images.

Download this Container Image

For those with access, this container image is available on cgr.dev:

docker pull cgr.dev/ORGANIZATION/kube-router:latest

Be sure to replace the ORGANIZATION placeholder with the name used for your organization's private repository within the Chainguard Registry.

Compatibility Notes

The kube-router image is a drop-in replacement for the upstream cloudnativelabs/kube-router image, with the following differences:

• It is built on Chainguard OS, so it is distroless and carries few-to-zero CVEs.
• It keeps the upstream layout: kube-router, gobgp, and the cni-install script all live under /usr/local/bin, the entrypoint is /usr/local/bin/kube-router, and the image runs as root.

Getting Started

kube-router runs as a privileged, host-networked DaemonSet on every node, and can replace kube-proxy, the CNI plugin, and the NetworkPolicy controller. Deploy it with the manifests from the upstream daemonset/ directory, which is the installation method the kube-router documentation describes.

generic-kuberouter-all-features.yaml is the self-contained manifest: it carries the ServiceAccount, RBAC, ConfigMap, and DaemonSet, and its init container writes the node-level kubeconfig that the other variants expect to already exist. Fetch it from the upstream repository:

curl -fsSLO https://raw.githubusercontent.com/cloudnativelabs/kube-router/master/daemonset/generic-kuberouter-all-features.yaml

The manifest ships two placeholders for you to fill in. %APISERVER% must be an address the pods can reach without cluster DNS, because the DaemonSet is host-networked and never sees CoreDNS. %CLUSTERCIDR% is the pod CIDR your cluster allocates from:

APISERVER="https://$(kubectl get nodes -o jsonpath='{.items[0].status.addresses[?(@.type=="InternalIP")].address}'):6443"
CLUSTERCIDR="$(kubectl get nodes -o jsonpath='{.items[0].spec.podCIDR}')"

sed -e "s|%APISERVER%|${APISERVER}|g" \
    -e "s|%CLUSTERCIDR%|${CLUSTERCIDR}|g" \
    -e "s|docker.io/cloudnativelabs/kube-router|cgr.dev/ORGANIZATION/kube-router:latest|g" \
    generic-kuberouter-all-features.yaml | kubectl apply -f -

Be sure to replace the ORGANIZATION placeholder with the name used for your organization's private repository within the Chainguard Registry.

Once the DaemonSet has rolled out, confirm the embedded BGP server is running by querying it with the bundled gobgp CLI from inside a pod:

kubectl -n kube-system rollout status ds/kube-router
kubectl -n kube-system exec ds/kube-router -c kube-router -- /usr/local/bin/gobgp global

daemon set "kube-router" successfully rolled out
AS:        64512
Router-ID: 192.168.183.2
Listening Port: 179, Addresses: 192.168.183.2

The other manifests in daemonset/ run narrower subsets, for example kube-router-firewall-daemonset.yaml for NetworkPolicy enforcement alone and kube-router-proxy-daemonset.yaml for the IPVS service proxy alone. Unlike the generic manifest, those ship no RBAC and do not create /var/lib/kube-router/kubeconfig, so you must supply both yourself before applying them.

Configuration

kube-router is configured through command-line flags, set in the DaemonSet's args. The three controllers are enabled independently, so you can run only the pieces you need:

• --run-router programs pod routes and advertises them over BGP. --cluster-asn sets the autonomous system number for your cluster, and defaults to 64512.
• --run-firewall enforces Kubernetes NetworkPolicy objects using iptables and ipset.
• --run-service-proxy load-balances ClusterIP and NodePort services using IPVS in place of kube-proxy.

--enable-cni controls whether kube-router installs its CNI configuration onto each node so that it acts as the cluster's CNI. If another CNI already owns pod networking, leave the router controller enabled for BGP advertisement and set --enable-cni=false.

Metrics are disabled unless you set --metrics-port, which none of the upstream manifests do. Add it to the DaemonSet's args if you want to scrape kube-router's Prometheus endpoint.

Documentation and Resources

• kube-router documentation
• Upstream project on GitHub
• Upstream DaemonSet manifests

What are Chainguard Containers?

Chainguard's free tier of Starter container images are built with Wolfi, our minimal Linux undistro.

All other Chainguard Containers are built with Chainguard OS, Chainguard's minimal Linux operating system designed to produce container images that meet the requirements of a more secure software supply chain.

The main features of Chainguard Containers include:

• Minimal design, without unnecessary software bloat
• Daily builds to ensure container images are up-to-date with available security patches
• High quality build-time SBOMs attesting to the provenance of all artifacts within the image
• Verifiable signatures provided by Sigstore
• Reproducible builds with Cosign and apko (read more about reproducibility)

For cases where you need container images with shells and package managers to build or debug, most Chainguard Containers come paired with a development, or -dev, variant.

In all other cases, including Chainguard Containers tagged as :latest or with a specific version number, the container images include only an open-source application and its runtime dependencies. These minimal container images typically do not contain a shell or package manager.

Although the -dev container image variants have similar security features as their more minimal versions, they include additional software that is typically not necessary in production environments. We recommend using multi-stage builds to copy artifacts from the -dev variant into a more minimal production image.

Need additional packages?

To improve security, Chainguard Containers include only essential dependencies. Need more packages? Chainguard customers can use Custom Assembly to add packages, either through the Console, chainctl, or API.

To use Custom Assembly in the Chainguard Console: navigate to the image you'd like to customize in your Organization's list of images, and click on the Customize image button at the top of the page.

Learn More

Refer to our Chainguard Containers documentation on Chainguard Academy. Chainguard also offers VMs and Libraries — contact us for access.

Trademarks

This software listing is packaged by Chainguard. The trademarks set forth in this offering are owned by their respective companies, and use of them does not imply any affiliation, sponsorship, or endorsement by such companies.