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Dynamic Kubernetes Cluster Registration (Preview)

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With dynamic Kubernetes cluster registration, you can manage the Kubernetes clusters connected to your Teleport cluster without needing to modify the configuration file of an individual Kubernetes Service instance.

Dynamic Kubernetes cluster registration is useful when you have deployed multiple Kubernetes Service instances or need to regularly reconfigure access to Kubernetes clusters in your instrastructure.

In this guide, we will show you how to set up dynamic Kubernetes cluster registration, then create, list, update, and delete Kubernetes clusters via tctl.

Prerequisites

  • A running Teleport cluster. For details on how to set this up, see one of our Getting Started guides.

  • The tctl admin tool and tsh client tool version >= 11.0.3.

    tctl version

    Teleport v11.0.3 go1.19

    tsh version

    Teleport v11.0.3 go1.19

    See Installation for details.

  • A running Teleport cluster. For details on how to set this up, see our Enterprise Getting Started guide.

  • The tctl admin tool and tsh client tool version >= 11.0.3, which you can download by visiting the customer portal.

    tctl version

    Teleport v11.0.3 go1.19

    tsh version

    Teleport v11.0.3 go1.19

  • A Teleport Cloud account. If you do not have one, visit the sign up page to begin your free trial.

  • The tctl admin tool and tsh client tool version >= 10.3.8. To download these tools, visit the Downloads page.

    tctl version

    Teleport v10.3.8 go1.19

    tsh version

    Teleport v10.3.8 go1.19

  • A Linux host where you will install the Teleport Kubernetes Service.

    Our teleport-kube-agent Helm chart does not support dynamic Kubernetes cluster registration.

  • A Kubernetes cluster to join to your Teleport cluster. You must have permissions to create namespaces, secrets, service accounts, cluster roles, and cluster role bindings in the cluster.

To connect to Teleport, log in to your cluster using tsh, then use tctl remotely:

tsh login --proxy=teleport.example.com [email protected]
tctl status

Cluster teleport.example.com

Version 11.0.3

CA pin sha256:abdc1245efgh5678abdc1245efgh5678abdc1245efgh5678abdc1245efgh5678

You can run subsequent tctl commands in this guide on your local machine.

For full privileges, you can also run tctl commands on your Auth Service host.

To connect to Teleport, log in to your cluster using tsh, then use tctl remotely:

tsh login --proxy=myinstance.teleport.sh [email protected]
tctl status

Cluster myinstance.teleport.sh

Version 10.3.8

CA pin sha256:sha-hash-here

You must run subsequent tctl commands in this guide on your local machine.

Step 1/3. Set up the Teleport Kubernetes Service

The Teleport Kubernetes Service proxies traffic from Teleport users to a Kubernetes API server so you can take advantage of passwordless authentication, role-based access controls, audit logging, and other Teleport features in order to manage access to Kubernetes.

In this step, you will install the Teleport Kubernetes Service on a Linux host and configure it to access any Kubernetes cluster you register with your Teleport cluster.

Get a join token

Establish trust between your Teleport cluster and your new Kubernetes Service instance by creating a join token:

tctl nodes add --roles=kube

The invite token: abcd123-insecure-do-not-use-this

This token will expire in 30 minutes.

Run this on the new node to join the cluster:

> teleport start \

--roles=kube \

--token=abcd123-insecure-do-not-use-this \

--ca-pin=sha256:abdc1245efgh5678abdc1245efgh5678abdc1245efgh5678abdc1245efgh5678 \

--auth-server=192.0.2.255:3025

Please note:

- This invitation token will expire in 30 minutes

- 192.0.2.255:3025 must be reachable from the new node

Copy the token and keep it somewhere safe so you can use it when running the Teleport Kubernetes Service.

Install the Teleport Kubernetes Service

Install the Teleport Kubernetes Service on your Linux host:

Download Teleport's PGP public key

sudo curl https://apt.releases.teleport.dev/gpg \ -o /usr/share/keyrings/teleport-archive-keyring.asc

Source variables about OS version

source /etc/os-release

Add the Teleport APT repository for v11. You'll need to update this

file for each major release of Teleport.

Note: if using a fork of Debian or Ubuntu you may need to use '$ID_LIKE'

and the codename your distro was forked from instead of '$ID' and '$VERSION_CODENAME'.

Supported versions are listed here: https://github.com/gravitational/teleport/blob/master/build.assets/tooling/cmd/build-os-package-repos/runners.go#L42-L67

echo "deb [signed-by=/usr/share/keyrings/teleport-archive-keyring.asc] \ https://apt.releases.teleport.dev/${ID?} ${VERSION_CODENAME?} stable/v11" \ | sudo tee /etc/apt/sources.list.d/teleport.list > /dev/null

sudo apt-get update
sudo apt-get install teleport

Source variables about OS version

source /etc/os-release

Add the Teleport YUM repository for v11. You'll need to update this

file for each major release of Teleport.

Note: if using a fork of RHEL/CentOS or Amazon Linux you may need to use '$ID_LIKE'

and the codename your distro was forked from instead of '$ID'

Supported versions are listed here: https://github.com/gravitational/teleport/blob/master/build.assets/tooling/cmd/build-os-package-repos/runners.go#L133-L153

sudo yum-config-manager --add-repo $(rpm --eval "https://yum.releases.teleport.dev/$ID/$VERSION_ID/Teleport/%{_arch}/stable/v11/teleport.repo")
sudo yum install teleport

Tip: Add /usr/local/bin to path used by sudo (so 'sudo tctl users add' will work as per the docs)

echo "Defaults secure_path = /sbin:/bin:/usr/sbin:/usr/bin:/usr/local/bin" > /etc/sudoers.d/secure_path

Optional: Using DNF on newer distributions

$ sudo dnf config-manager --add-repo https://rpm.releases.teleport.dev/teleport.repo

$ sudo dnf install teleport

curl https://get.gravitational.com/teleport-v11.0.3-linux-amd64-bin.tar.gz.sha256

<checksum> <filename>

curl -O https://get.gravitational.com/teleport-v11.0.3-linux-amd64-bin.tar.gz
shasum -a 256 teleport-v11.0.3-linux-amd64-bin.tar.gz

Verify that the checksums match

tar -xzf teleport-v11.0.3-linux-amd64-bin.tar.gz
cd teleport
sudo ./install
curl https://get.gravitational.com/teleport-v11.0.3-linux-arm-bin.tar.gz.sha256

<checksum> <filename>

curl -O https://get.gravitational.com/teleport-v11.0.3-linux-arm-bin.tar.gz
shasum -a 256 teleport-v11.0.3-linux-arm-bin.tar.gz

Verify that the checksums match

tar -xzf teleport-v11.0.3-linux-arm-bin.tar.gz
cd teleport
sudo ./install
curl https://get.gravitational.com/teleport-v11.0.3-linux-arm64-bin.tar.gz.sha256

<checksum> <filename>

curl -O https://get.gravitational.com/teleport-v11.0.3-linux-arm64-bin.tar.gz
shasum -a 256 teleport-v11.0.3-linux-arm64-bin.tar.gz

Verify that the checksums match

tar -xzf teleport-v11.0.3-linux-arm64-bin.tar.gz
cd teleport
sudo ./install

Using this APT repo may result in breaking upgrades upon "apt upgrade" as all major versions will be

published under the same component. We recommend following the instructions in the

"Debian/Ubuntu (DEB)" tab instead.

Download Teleport's PGP public key

sudo curl https://deb.releases.teleport.dev/teleport-pubkey.asc \ -o /usr/share/keyrings/teleport-archive-keyring.asc

Add the Teleport APT repository

echo "deb [signed-by=/usr/share/keyrings/teleport-archive-keyring.asc] https://deb.releases.teleport.dev/ stable main" \ | sudo tee /etc/apt/sources.list.d/teleport.list > /dev/null

sudo apt-get update
sudo apt-get install teleport
sudo yum-config-manager --add-repo https://rpm.releases.teleport.dev/teleport.repo
sudo yum install teleport

Optional: Using DNF on newer distributions

$ sudo dnf config-manager --add-repo https://rpm.releases.teleport.dev/teleport.repo

$ sudo dnf install teleport

Configure the Teleport Kubernetes Service

On the host where you will run the Teleport Kubernetes Service, run the following command to create a base configuration for your Teleport instance, assigning PROXY_SERVICE to the host and port of your Teleport Proxy Service or Teleport Cloud tenant and TOKEN to the join token we created earlier:

e.g., teleport.example.com:443

PROXY_SERVICE=

e.g., abcd123-insecure-do-not-use-this;

TOKEN=
;
sudo teleport configure \--proxy=${PROXY_SERVICE?} \--roles=kube \--token=${TOKEN?} \-o file

Edit your configuration file at /etc/teleport.yaml to include the following:

kubernetes_service:
  enabled: "yes"
  resources:
  - labels:
      "*": "*"

This configuration enables your Kubernetes Service instance to connect to any Kubernetes clusters you register with your Teleport cluster. This is because the resources[0].labels field includes the wildcard pattern ("*": "*"), which allows this Kubernetes Service instance to connect to Kubernetes cluster resources with any label key or value.

You can configure a Kubernetes Service instance to watch for a subset of Kubernetes clusters by including specific label keys and values instead of wildcard characters:

resources:
- labels:
    "env": "prod"
    "region": "us-east-2"
- labels:
    "env": "test"
    "region": "us-west-1"

For the Kubernetes Service to register a cluster, any of the items in resources must match the cluster's labels. For an item in resources to match, all of the labels entries within that item must match the cluster's labels.

For example, a cluster with the labels env:prod and region:us-west-1 would not match the configuration above, since it only matches the env:prod label in the first resources item and the region:us-west-1 label in the second resources item.

However, a cluster with env:test and region:us-west-1 would match, since it matches both labels given in the second resources item.

When you create dynamic Kubernetes cluster resources later in this guide, you can assign them labels to ensure that only specific Kubernetes Service instances will watch for them.

Run the Teleport Kubernetes Service

On the host where you will run the Teleport Kubernetes Service, execute the following command, depending on whether you installed Teleport using a package manager or via a TAR archive:

sudo systemctl start teleport
sudo teleport start

Step 2/3. Authorize your user

To enable dynamic Kubernetes cluster registration in Teleport, you will need to authorize your user to access the Kubernetes clusters you want to register with Teleport. We will configure this access in this step, both in Teleport and on your Kubernetes cluster.

Allow access to your Kubernetes cluster

Ensure that you are in the correct Kubernetes context for the cluster you would like to enable access to.

Retrieve all available contexts:

kubectl config get-contexts

Switch to your context, replacing CONTEXT_NAME with the name of your chosen context:

kubectl config use-context CONTEXT_NAME

Switched to context CONTEXT_NAME

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.

Authorize your user to manage Kubernetes clusters

Teleport tracks Kubernetes clusters in your infrastructure via dynamic kube_cluster resources. To manage access to Kubernetes clusters with Teleport, your user will need permissions to manage these resources.

In the previous section, you authorized your user to access all Kubernetes clusters registered in your Teleport cluster. Now that you can access these clusters, create a role that enables you to manage them.

Create a role definition called kube-manager.yaml with the following content:

kind: role
metadata:
  name: kube-manager
spec:
  allow:
    rules:
    - resources:
      - kube_cluster
      verbs:
      - list
      - create
      - read
      - update
      - delete
version: v5

Retrieve your user:

e.g., myuser

TELEPORT_USER=
tctl get user/${TELEPORT_USER?} > user.yaml

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

   roles:
   - access
   - auditor
   - kube-user
+  - kube-manager

Apply your changes:

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

Log out of your cluster and log in again to assume the new role.

Step 3/3. Manage dynamic Kubernetes cluster resources

Now that your Teleport user has permissions to manage Kubernetes cluster resources, we will show you how to create, list, update, and delete them.

Create a kubeconfig

In this section, you will create a Kubernetes Config resource, or kubeconfig, that your Teleport cluster will use to authenticate to your Kubernetes cluster.

When you signed into Teleport earlier in this guide, tsh may have changed your Kubernetes context to one based on your Teleport cluster, so make sure you update your Kubernetes context to match the cluster you would like to connect to Teleport:

kubectl config get-contexts

Assign CONTEXT_NAME to your chosen context

kubectl config use-context CONTEXT_NAME

On your workstation, download Teleport's get-kubeconfig.sh script, which you will use to generate the kubeconfig:

curl -OL \https://raw.githubusercontent.com/gravitational/teleport/master/examples/k8s-auth/get-kubeconfig.sh

The script creates a service account for the Teleport Kubernetes Service that can get Kubernetes pods as well as impersonate users, groups, and other service accounts. The Teleport Kubernetes Service uses this service account to manage access to resources in your Kubernetes cluster. The script also ensures that there is a Kubernetes Secret in your cluster to store service account credentials.

get-kubeconfig.sh creates a namespace called teleport for the resources it deploys, though you can choose a different name by assigning the TELEPORT_NAMESPACE environment variable in the shell where you run the script.

After creating resources, get-kubeconfig.sh writes a new kubeconfig to a file called kubeconfig in the directory where you run the script.

Run the get-kubeconfig.sh script:

bash get-kubeconfig.sh

The script is successful if you see this message:

Done!

Ignore the script's instructions to copy the generated kubeconfig file to the Teleport Proxy Service. In the next section, we will show you how to use the kubeconfig file when creating a dynamic kube_cluster resource.

Create a Kubernetes cluster resource

Define a kube_cluster resource with the following content in a file called kube_cluster.yaml:

kind: kube_cluster
version: v3
metadata:
  name: mycluster
spec:
  kubeconfig: |

The spec.kubeconfig field in the snippet above begins a multi-line string. Below, you will include the contents of the kubeconfig file as its value.

Since spec.kubeconfig must be a base64-encoded string, convert the kubeconfig file to base64, then indent it and add it to the kube_cluster.yaml resource definition using the following command:

printf " %s" $(cat kubeconfig | base64) >> kube_cluster.yaml

You can add labels to the kube_cluster resource, allowing you to manage access to specific clusters from your Teleport roles or Kubernetes Service instances.

Labels can either be static or dynamic. Static labels are key/value pairs. This example defines the env=prod and team=dev labels:

kind: kube_cluster
version: v3
metadata:
  name: mycluster
  labels:
    env: prod
    team: dev
spec:
  kubeconfig: KUBECONFIG

You can also add dynamic labels, which define shell commands that a Kubernetes Service instance will execute in order to generate labels. To do so, edit the spec.dynamic_labels field of a kube_cluster resource.

This example runs the python3 get_region.py command to fetch the region in which the Kubernetes Service is deployed and assign the result to the region key:

kind: kube_cluster
version: v3
metadata:
  name: mycluster
spec:
  kubeconfig: KUBECONFIG
  dynamic_labels:
    region:
      period: "24h"
      command: ["python3", "get_region.py"]

When defining a dynamic label, the key within the spec.dynamic_labels field behaves the same as keys within the metadata.labels field, indicating the key of the label.

The Kubernetes Service obtains a value for that key by running the command given in command every period. command is an array of strings, where the first element indicates the command to execute and each subsequent element indicates an argument.

period is a Go duration string, which includes a number and a unit of time. Supported units are ns, us (or µs), ms, s, m, and h. The example above configures the Kubernetes Service to run the command every day.

To create the kube_cluster resource, run the following command:

tctl create kube_cluster.yaml

kubernetes cluster "mycluster" has been created

Access your new Kubernetes cluster

Instances of the Teleport Kubernetes Service watch for newly created or updated kube_cluster resources. When you create the kube_cluster resource, any Kubernetes Service instances you have configured to track that cluster's labels will register that cluster and enable access to it via Teleport.

As a result, you should now see the cluster you registered above when you run tsh kube ls:

tsh kube ls

Kube Cluster Name Labels Selected

----------------- --------------------------- --------

mycluster teleport.dev/origin=dynamic

The teleport.dev/origin=dynamic label indicates that the cluster was registered dynamically.

You can also log in to the cluster you just registered:

tsh kube login mycluster

Logged into kubernetes cluster "mycluster". Try 'kubectl version' to test the

connection.

List Kubernetes cluster resources

You can list kube_cluster resources with the following command:

tctl get kube_clusters

Update a Kubernetes cluster resource

To update the kube_cluster resource you created earlier, execute the following command to retrieve the resource as it exists on the Auth Service's backend:

tctl get kube_clusters/mycluster > kube_cluster.yaml

Edit the kube_cluster.yaml file to add a label to your kube_cluster:

  kind: kube_cluster
  metadata:
    id: 9999999999999999999
    labels:
      teleport.dev/origin: dynamic
+     env: test
    name: mycluster
  spec:
    aws: {}
    azure: {}
    kubeconfig: KUBECONFIG
  version: v3

Update the resource:

tctl create -f kube_cluster.yaml

kubernetes cluster "mycluster" has been updated

You should now see the updated labels:

tsh kube ls

Kube Cluster Name Labels Selected

----------------- ------------------------------------ --------

mycluster env=test teleport.dev/origin=dynamic *

If the updated kube_cluster resource's labels no longer match the ones a Teleport Kubernetes Service instance is configured to watch, the instance will unregister and stop proxying the Kubernetes cluster.

Delete Kubernetes cluster resources

To delete the kube_cluster resource you created earlier, run the following command:

tctl rm kube_clusters/mycluster

kubernetes cluster "mycluster" has been deleted

This also unregisters the Kubernetes cluster from Teleport:

tsh kube ls

Kube Cluster Name Labels Selected

----------------- ------ --------

Next steps

In this guide, we showed you how to manage kube_cluster resources using tctl. If you are interested in other ways you can manage access to Kubernetes clusters via Teleport, check out the following guides: