Simplifying FedRAMP Compliance with Teleport
Jun 27
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Register a Kubernetes Cluster with a Static kubeconfig

While you can register a Kubernetes cluster with Teleport by running the Teleport Kubernetes Service on that cluster, you can also run the Teleport Kubernetes Service on a Linux host outside the cluster. This is useful if you want to decouple your Teleport deployment from the Kubernetes clusters you want to manage access to.

In this setup, the Teleport Kubernetes Service uses a kubeconfig file to authenticate to the API server of your chosen Kubernetes cluster.

When running Teleport in production, you should adhere to the following best practices to avoid security incidents:

  • Avoid using sudo in production environments unless it's necessary.
  • Create new, non-root, users and use test instances for experimenting with Teleport.
  • Run Teleport's services as a non-root user unless required. Only the SSH Service requires root access. Note that you will need root permissions (or the CAP_NET_BIND_SERVICE capability) to make Teleport listen on a port numbered < 1024 (e.g. 443).
  • Follow the principle of least privilege. Don't give users permissive roles when more a restrictive role will do. For example, don't assign users the built-in access,editor roles, which give them permissions to access and edit all cluster resources. Instead, define roles with the minimum required permissions for each user and configure access requests to provide temporary elevated permissions.
  • When you enroll Teleport resources—for example, new databases or applications—you should save the invitation token to a file. If you enter the token directly on the command line, a malicious user could view it by running the history command on a compromised system.

You should note that these practices aren't necessarily reflected in the examples used in documentation. Examples in the documentation are primarily intended for demonstration and for development environments.

Prerequisites

  • A running Teleport cluster version 16.0.1 or above. If you want to get started with Teleport, sign up for a free trial or set up a demo environment.

  • The tctl admin tool and tsh client tool.

    Visit Installation for instructions on downloading tctl and tsh.

  • A Kubernetes cluster you would like to access.
  • A Linux host deployed on your own infrastructure to run the Teleport Kubernetes Service. This can run outside of your Kubernetes cluster.
  • The kubectl command line tool installed on your workstation.
  • To check that you can connect to your Teleport cluster, sign in with tsh login, then verify that you can run tctl commands using your current credentials. tctl is supported on macOS and Linux machines. For example:
    tsh login --proxy=teleport.example.com --user=[email protected]
    tctl status

    Cluster teleport.example.com

    Version 16.0.1

    CA pin sha256:abdc1245efgh5678abdc1245efgh5678abdc1245efgh5678abdc1245efgh5678

    If you can connect to the cluster and run the tctl status command, you can use your current credentials to run subsequent tctl commands from your workstation. If you host your own Teleport cluster, you can also run tctl commands on the computer that hosts the Teleport Auth Service for full permissions.

Step 1/4. Generate a kubeconfig file

The Teleport Kubernetes Service uses a kubeconfig file to authenticate to your Kubernetes cluster. In this section, we will generate a kubeconfig file so we can configure the Teleport Kubernetes Service to use it later in this guide.

Ensure your context is correct

First, configure your local kubectl command to point at the Kubernetes cluster you want to register. You can use the following command to verify that the correct cluster is selected:

kubectl config get-contexts

Use this command to switch to the cluster assigned to CONTEXT_NAME:

e.g., my-context

CONTEXT_NAME=context-name
kubectl config use-context ${CONTEXT_NAME?}

Run the script

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

curl -OL \https://raw.githubusercontent.com/gravitational/teleport/v16.0.1/examples/k8s-auth/get-kubeconfig.sh

get-kubeconfig.sh 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 also 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 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!

Move the kubeconfig file to the host you are using to run the Teleport Kubernetes Service. We will assume that the kubeconfig file exists at /var/lib/teleport/kubeconfig.

You can connect multiple Kubernetes clusters to Teleport from one kubeconfig file if it contains multiple entries. Use merge-kubeconfigs.sh to combine multiple kubeconfig files generated by get-kubeconfig.sh.

Step 2/4. Set up the Teleport Kubernetes Service

In this step, you will install the Teleport Kubernetes Service and configure it to use the kubeconfig file you generated to access a Kubernetes cluster.

Get a join token

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

tctl tokens add --type=kube --format=text --ttl=1h
abcd123-insecure-do-not-use-this

On the host where you are running the Teleport Kubernetes Service, create a file called /tmp/token that consists only of your token:

echo join-token | sudo tee /tmp/token

Install the Teleport Kubernetes Service

Run the following commands on the host where you will install the Teleport Kubernetes Service:

Install Teleport on your Linux server:

  1. Assign edition to one of the following, depending on your Teleport edition:

    EditionValue
    Teleport Enterprise Cloudcloud
    Teleport Enterprise (Self-Hosted)enterprise
    Teleport Community Editionoss
  2. Get the version of Teleport to install. If you have automatic agent updates enabled in your cluster, query the latest Teleport version that is compatible with the updater:

    TELEPORT_DOMAIN=example.teleport.com
    TELEPORT_VERSION="$(curl https://$TELEPORT_DOMAIN/v1/webapi/automaticupgrades/channel/default/version | sed 's/v//')"

    Otherwise, get the version of your Teleport cluster:

    TELEPORT_DOMAIN=example.teleport.com
    TELEPORT_VERSION="$(curl https://$TELEPORT_DOMAIN/v1/webapi/ping | jq -r '.server_version')"
  3. Install Teleport on your Linux server:

    curl https://goteleport.com/static/install.sh | bash -s ${TELEPORT_VERSION} edition

    The installation script detects the package manager on your Linux server and uses it to install Teleport binaries. To customize your installation, learn about the Teleport package repositories in the installation guide.

Configure the Teleport Kubernetes Service

On the host where you will run the Teleport Kubernetes Service, create a file at /etc/teleport.yaml with the following content:

version: v3
teleport:
  join_params:
    token_name: "/tmp/token"
    method: token
  proxy_server: teleport.example.com:443
auth_service:
  enabled: off
proxy_service:
  enabled: off
ssh_service:
  enabled: off
kubernetes_service:
  enabled: "yes"
  kubeconfig_file: "/var/lib/teleport/kubeconfig"
  labels:
    "region": "us-east1"

Edit /etc/teleport.yaml to replace teleport.example.com:443 with the host and port of your Teleport Proxy Service or Teleport Cloud tenant, e.g., mytenant.teleport.sh:443.

Warning

When using kubeconfig_file, Amazon EKS users may need to replace illegal characters in the context names. Supported characters are alphanumeric characters, ., _, and -. EKS typically includes : and @ in their kubeconfig files, which are not allowed in Teleport.

Start the Teleport Kubernetes Service

Configure the Teleport Kubernetes Service to start automatically when the host boots up by creating a systemd service for it. The instructions depend on how you installed the Teleport Kubernetes Service.

On the host where you will run the Teleport Kubernetes Service, enable and start Teleport:

sudo systemctl enable teleport
sudo systemctl start teleport

On the host where you will run the Teleport Kubernetes Service, create a systemd service configuration for Teleport, enable the Teleport service, and start Teleport:

sudo teleport install systemd -o /etc/systemd/system/teleport.service
sudo systemctl enable teleport
sudo systemctl start teleport

You can check the status of the Teleport Kubernetes Service with systemctl status teleport and view its logs with journalctl -fu teleport.

Step 3/4. Grant access to your Teleport user

Enable your Teleport user to access resources in your Kubernetes cluster so you can connect to the cluster later in this guide.

To authenticate to a Kubernetes cluster via Teleport, your Teleport user's roles must allow access as at least one Kubernetes user or group.

  1. Retrieve a list of your current user's Teleport roles. The example below requires the jq utility for parsing JSON:

    CURRENT_ROLES=$(tsh status -f json | jq -r '.active.roles | join ("\n")')
  2. Retrieve the Kubernetes groups your roles allow you to access:

    echo "$CURRENT_ROLES" | xargs -I{} tctl get roles/{} --format json | \ jq '.[0].spec.allow.kubernetes_groups[]?'
  3. Retrieve the Kubernetes users your roles allow you to access:

    echo "$CURRENT_ROLES" | xargs -I{} tctl get roles/{} --format json | \ jq '.[0].spec.allow.kubernetes_users[]?'
  4. If the output of one of the previous two commands is non-empty, your user can access at least one Kubernetes user or group, so you can proceed to the next step.

  5. If both lists are empty, create a Teleport role for the purpose of this guide that can view Kubernetes resources in your cluster.

    Create a file called kube-access.yaml with the following content:

    kind: role
    metadata:
      name: kube-access
    version: v7
    spec:
      allow:
        kubernetes_labels:
          '*': '*'
        kubernetes_resources:
          - kind: '*'
            namespace: '*'
            name: '*'
            verbs: ['*']
        kubernetes_groups:
        - viewers
      deny: {}
    
  6. Apply your changes:

    tctl create -f kube-access.yaml
  7. Assign the kube-access role to your Teleport user by running the appropriate commands for your authentication provider:

    1. Retrieve your local user's roles as a comma-separated list:

      ROLES=$(tsh status -f json | jq -r '.active.roles | join(",")')
    2. Edit your local user to add the new role:

      tctl users update $(tsh status -f json | jq -r '.active.username') \ --set-roles "${ROLES?},kube-access"
    3. Sign out of the Teleport cluster and sign in again to assume the new role.

    1. Retrieve your github authentication connector:

      tctl get github/github --with-secrets > github.yaml

      Note that the --with-secrets flag adds the value of spec.signing_key_pair.private_key to the github.yaml file. Because this key contains a sensitive value, you should remove the github.yaml file immediately after updating the resource.

    2. Edit github.yaml, adding kube-access to the teams_to_roles section.

      The team you should map to this role depends on how you have designed your organization's role-based access controls (RBAC). However, the team must include your user account and should be the smallest team possible within your organization.

      Here is an example:

        teams_to_roles:
          - organization: octocats
            team: admins
            roles:
              - access
      +       - kube-access
      
    3. Apply your changes:

      tctl create -f github.yaml
    4. Sign out of the Teleport cluster and sign in again to assume the new role.

    1. Retrieve your saml configuration resource:

      tctl get --with-secrets saml/mysaml > saml.yaml

      Note that the --with-secrets flag adds the value of spec.signing_key_pair.private_key to the saml.yaml file. Because this key contains a sensitive value, you should remove the saml.yaml file immediately after updating the resource.

    2. Edit saml.yaml, adding kube-access to the attributes_to_roles section.

      The attribute you should map to this role depends on how you have designed your organization's role-based access controls (RBAC). However, the group must include your user account and should be the smallest group possible within your organization.

      Here is an example:

        attributes_to_roles:
          - name: "groups"
            value: "my-group"
            roles:
              - access
      +       - kube-access
      
    3. Apply your changes:

      tctl create -f saml.yaml
    4. Sign out of the Teleport cluster and sign in again to assume the new role.

    1. Retrieve your oidc configuration resource:

      tctl get oidc/myoidc --with-secrets > oidc.yaml

      Note that the --with-secrets flag adds the value of spec.signing_key_pair.private_key to the oidc.yaml file. Because this key contains a sensitive value, you should remove the oidc.yaml file immediately after updating the resource.

    2. Edit oidc.yaml, adding kube-access to the claims_to_roles section.

      The claim you should map to this role depends on how you have designed your organization's role-based access controls (RBAC). However, the group must include your user account and should be the smallest group possible within your organization.

      Here is an example:

        claims_to_roles:
          - name: "groups"
            value: "my-group"
            roles:
              - access
      +       - kube-access
      
    3. Apply your changes:

      tctl create -f oidc.yaml
    4. Sign out of the Teleport cluster and sign in again to assume the new role.

  8. Configure the viewers group in your Kubernetes cluster to have the built-in view ClusterRole. When your Teleport user assumes the kube-access role and sends requests to the Kubernetes API server, the Teleport Kubernetes Service impersonates the viewers group and proxies the requests.

    Create a file called viewers-bind.yaml with the following contents, binding the built-in view ClusterRole with the viewers group you enabled your Teleport user to access:

    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
    
  9. Apply the ClusterRoleBinding with kubectl:

    kubectl apply -f viewers-bind.yaml

Step 4/4. Access your Kubernetes cluster

After Teleport starts with the above config, you should be able to see all new clusters:

tsh kube ls
Kube Cluster Name Labels Selected--------------------------------------- ------ --------my-cluster region=us-east-1

To access your cluster, run the following command, replacing my-cluster with the name of the cluster you would like to access:

tsh kube login my-cluster
Logged into kubernetes cluster "my-cluster". Try 'kubectl version' to test the connection.