website/content/en/docs/tasks/extend-kubernetes/setup-konnectivity.md

title	content_type	weight
Set up Konnectivity service	task	70

The Konnectivity service provides a TCP level proxy for the control plane to cluster communication.

{{% heading "prerequisites" %}}

You need to have a Kubernetes cluster, and the kubectl command-line tool must be configured to communicate with your cluster. It is recommended to run this tutorial on a cluster with at least two nodes that are not acting as control plane hosts. If you do not already have a cluster, you can create one by using minikube.

Configure the Konnectivity service

The following steps require an egress configuration, for example:

{{< codenew file="admin/konnectivity/egress-selector-configuration.yaml" >}}

You need to configure the API Server to use the Konnectivity service and direct the network traffic to the cluster nodes:

1. Make sure that Service Account Token Volume Projection feature enabled in your cluster. It is enabled by default since Kubernetes v1.20.
2. Create an egress configuration file such as admin/konnectivity/egress-selector-configuration.yaml.
3. Set the --egress-selector-config-file flag of the API Server to the path of your API Server egress configuration file.
4. If you use UDS connection, add volumes config to the kube-apiserver:

   spec:
     containers:
       volumeMounts:
       - name: konnectivity-uds
         mountPath: /etc/kubernetes/konnectivity-server
         readOnly: false
     volumes:
     - name: konnectivity-uds
       hostPath:
         path: /etc/kubernetes/konnectivity-server
         type: DirectoryOrCreate
   

Generate or obtain a certificate and kubeconfig for konnectivity-server. For example, you can use the OpenSSL command line tool to issue a X.509 certificate, using the cluster CA certificate /etc/kubernetes/pki/ca.crt from a control-plane host.

openssl req -subj "/CN=system:konnectivity-server" -new -newkey rsa:2048 -nodes -out konnectivity.csr -keyout konnectivity.key -out konnectivity.csr
openssl x509 -req -in konnectivity.csr -CA /etc/kubernetes/pki/ca.crt -CAkey /etc/kubernetes/pki/ca.key -CAcreateserial -out konnectivity.crt -days 375 -sha256
SERVER=$(kubectl config view -o jsonpath='{.clusters..server}')
kubectl --kubeconfig /etc/kubernetes/konnectivity-server.conf config set-credentials system:konnectivity-server --client-certificate konnectivity.crt --client-key konnectivity.key --embed-certs=true
kubectl --kubeconfig /etc/kubernetes/konnectivity-server.conf config set-cluster kubernetes --server "$SERVER" --certificate-authority /etc/kubernetes/pki/ca.crt --embed-certs=true
kubectl --kubeconfig /etc/kubernetes/konnectivity-server.conf config set-context system:konnectivity-server@kubernetes --cluster kubernetes --user system:konnectivity-server
kubectl --kubeconfig /etc/kubernetes/konnectivity-server.conf config use-context system:konnectivity-server@kubernetes
rm -f konnectivity.crt konnectivity.key konnectivity.csr

Next, you need to deploy the Konnectivity server and agents. kubernetes-sigs/apiserver-network-proxy is a reference implementation.

Deploy the Konnectivity server on your control plane node. The provided konnectivity-server.yaml manifest assumes that the Kubernetes components are deployed as a {{< glossary_tooltip text="static Pod" term_id="static-pod" >}} in your cluster. If not, you can deploy the Konnectivity server as a DaemonSet.

{{< codenew file="admin/konnectivity/konnectivity-server.yaml" >}}

Then deploy the Konnectivity agents in your cluster:

{{< codenew file="admin/konnectivity/konnectivity-agent.yaml" >}}

Last, if RBAC is enabled in your cluster, create the relevant RBAC rules:

{{< codenew file="admin/konnectivity/konnectivity-rbac.yaml" >}}