Connect a Kubernetes Cluster to Teleport

In this guide, we will show you how to register a Kubernetes cluster with Teleport by deploying the Teleport Kubernetes Service on the Kubernetes cluster you want to register.

In this setup, the Teleport Kubernetes Service pod detects that it is running on Kubernetes and registers the cluster automatically.

Prerequisites

• The jq tool to process JSON output. This is available via common package managers.

• Kubernetes >= v1.17.0
• Helm >= 3.4.2

Verify that Helm and Kubernetes are installed and up to date.

helm version
version.BuildInfo{Version:"v3.4.2"}
kubectl version
Client Version: version.Info{Major:"1", Minor:"17+"}
Server Version: version.Info{Major:"1", Minor:"17+"}

tsh login --proxy=teleport.example.com [email protected]
tctl status
Cluster  teleport.example.com
Version  11.0.3
CA pin   sha256:abdc1245efgh5678abdc1245efgh5678abdc1245efgh5678abdc1245efgh5678

tsh login --proxy=myinstance.teleport.sh [email protected]
tctl status
Cluster  myinstance.teleport.sh
Version  10.3.8
CA pin   sha256:sha-hash-here

Deployment overview

In this guide, we deploy the Teleport Kubernetes Service, which connects Kubernetes cluster cookie to Teleport cluster tele.example.com:

Step 1/3. Get a join token

In order to start the Teleport Kubernetes Service, we will need to request a join token from the Teleport Auth Service:

Create a join token for the Teleport Kubernetes Service to authenticate
TOKEN=$(tctl nodes add --roles=kube --ttl=10000h --format=json | jq -r '.[0]')
echo $TOKEN

Step 2/3. Deploy teleport-kube-agent

To allow Helm to install charts that are hosted in the Teleport Helm repository, use helm repo add:

helm repo add teleport https://charts.releases.teleport.dev

To update the cache of charts from the remote repository, run helm repo update:

helm repo update

PROXY_ADDR=tele.example.com:443
Install Kubernetes agent. It dials back to the Teleport cluster at $PROXY_ADDR
CLUSTER=cookie
helm install teleport-agent teleport/teleport-kube-agent --set kubeClusterName=${CLUSTER?} \  --set proxyAddr=${PROXY_ADDR?} --set authToken=${TOKEN?} --create-namespace --namespace=teleport-agent

PROXY_ADDR=mytenant.teleport.sh:443
Install Kubernetes agent. It dials back to the Teleport cluster at $PROXY_ADDR
CLUSTER=cookie
Run the helm install specifying to match to the Teleport Cloud version of Teleport
helm install teleport-agent teleport/teleport-kube-agent --set kubeClusterName=${CLUSTER?} \  --set proxyAddr=${PROXY_ADDR?} --set authToken=${TOKEN?} --create-namespace --namespace=teleport-agent \  --set teleportVersionOverride=10.3.8

Step 3/3 Access your Kubernetes cluster

Kubernetes authentication

To authenticate to a Kubernetes cluster via Teleport, your Teleport roles must allow access as at least one Kubernetes user or group. Ensure that you have a Teleport role that grants access to the cluster you plan to interact with.

Run the following command to get the Kubernetes user for your current context:

kubectl config view \-o jsonpath="{.contexts[?(@.name==\"$(kubectl config current-context)\")].context.user}"

Create a file called kube-access.yaml with the following content, replacing USER with the output of the command above.

kind: role
metadata:
  name: kube-access
version: v5
spec:
  allow:
    kubernetes_labels:
      '*': '*'
    kubernetes_groups:
    - viewers
    kubernetes_users:
    - USER
  deny: {}

Retrieve your Teleport user:

e.g., myuser
TELEPORT_USER=
tctl get user/${TELEPORT_USER?} > user.yaml

Add kube-access to your Teleport user's list of roles:

   roles:
+  - kube-access

Apply your changes:

tctl create -f kube-access.yaml
tctl create -f user.yaml

Now that Teleport RBAC is configured, you can authenticate to your Kubernetes cluster via Teleport. To interact with your Kubernetes cluster, you will need to configure authorization within Kubernetes.

Kubernetes authorization

To configure authorization within your Kubernetes cluster, you need to create Kubernetes RoleBindings or ClusterRoleBindings that grant permissions to the subjects listed in kubernetes_users and kubernetes_groups.

For example, you can grant some limited read-only permissions to the viewers group used in the kube-access role defined above:

Create a file called viewers-bind.yaml with the following contents:

apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
  name: viewers-crb
subjects:
- kind: Group
  # Bind the group "viewers", corresponding to the kubernetes_groups we assigned our "kube-access" role above
  name: viewers
  apiGroup: rbac.authorization.k8s.io
roleRef:
  kind: ClusterRole
  # "view" is a default ClusterRole that grants read-only access to resources
  # See: https://kubernetes.io/docs/reference/access-authn-authz/rbac/#user-facing-roles
  name: view
  apiGroup: rbac.authorization.k8s.io

Apply the ClusterRoleBinding with kubectl:

kubectl apply -f viewers-bind.yaml

Log out of Teleport and log in again.

View pods in your cluster

List connected clusters using tsh kube ls and switch between them using tsh kube login:

tsh kube ls
Kube Cluster Name Selected
----------------- --------
cookie
kubeconfig now points to the cookie cluster
tsh kube login cookie
Logged into kubernetes cluster "cookie". Try 'kubectl version' to test the connection.
kubectl command executed on `cookie` but is routed through the Teleport cluster.
kubectl get pods

Next Steps

• Take a look at a kube-agent helm chart reference for a full list of parameters.