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Version: 14.x

Teleport GKE Auto-Discovery

The Teleport Discovery Service can automatically register your Google Kubernetes Engine (GKE) clusters with Teleport. With Teleport Kubernetes Discovery, you can configure the Teleport Kubernetes Service and Discovery Service once, then create GKE clusters without needing to register them with Teleport after each creation.

In this guide, we will show you how to get started with Teleport Kubernetes Discovery for GKE.

Overview​

Teleport Kubernetes Auto-Discovery involves two components.

The first, the Discovery Service, is responsible for watching your cloud provider and checking if there are any new clusters or if there have been any modifications to previously discovered clusters. The second, the Kubernetes Service, monitors the clusters created by the Discovery Service. It proxies communications between users and the API servers of these clusters.

tip

This guide presents the Discovery Service and Kubernetes Service running in the same process, however both can run independently and on different machines.

For example, you can run an instance of the Kubernetes Service in each Kubernetes cluster you want to register with Teleport, and an instance of the Discovery Service in any network you wish.

Prerequisites​

  • A running Teleport cluster version 14.3.33 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 Google Cloud account with permissions to create GKE clusters, IAM roles, and service accounts.
  • The gcloud CLI tool. Follow the Google Cloud documentation page to install and authenticate to gcloud.
  • One or more GKE clusters running. Your Kubernetes user must have permissions to create ClusterRole and ClusterRoleBinding resources in your clusters.
  • A Linux host where you will run the Teleport Discovery and Kubernetes services. You can run this host on any cloud provider or even use a local machine.
  • 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 [email protected]
    $ tctl status
    # Cluster  teleport.example.com
    # Version  14.3.33
    # 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 1/3. Obtain Google Cloud credentials​

The Teleport Discovery Service and Kubernetes Service use a Google Cloud service account to discover GKE clusters and manage access from Teleport users. In this step, you will create a service account and download a credentials file for the Teleport Discovery Service.

Create an IAM role for the Discovery Service​

The Teleport Discovery Service needs permissions to retrieve GKE clusters associated with your Google Cloud project.

To grant these permissions, create a file called GKEKubernetesAutoDisc.yaml with the following content:

title: GKE Cluster Discoverer
description: "Get and list GKE clusters"
stage: GA
includedPermissions:
- container.clusters.get
- container.clusters.list

Create the role, assigning the --project flag to the name of your Google Cloud project:

$ gcloud iam roles create GKEKubernetesAutoDisc \
  --project=google-cloud-project \
  --file=GKEKubernetesAutoDisc.yaml

Create an IAM role for the Kubernetes Service​

The Teleport Kubernetes Service needs Google Cloud IAM permissions in order to forward user traffic to your GKE clusters.

Create a file called GKEAccessManager.yaml with the following content:

title: GKE Cluster Access Manager
description: "Manage access to GKE clusters"
stage: GA
includedPermissions:
- container.clusters.get
- container.clusters.impersonate
- container.pods.get
- container.selfSubjectAccessReviews.create
- container.selfSubjectRulesReviews.create

Create the role, assigning the --project flag to the name of your Google Cloud project. If you receive a prompt indicating that certain permissions are in TESTING, enter y:

$ gcloud iam roles create GKEAccessManager \
  --project=google-cloud-project \
  --file=GKEAccessManager.yaml

Create a service account​

Now that you have declared roles for the Discovery Service and Kubernetes Service, create a service account so you can assign these roles.

Run the following command to create a service account called teleport-discovery-kubernetes:

$ gcloud iam service-accounts create teleport-discovery-kubernetes \
  --description="Teleport Discovery Service and Kubernetes Service" \
  --display-name="teleport-discovery-kubernetes"

Grant the roles you defined earlier to your service account, assigning PROJECT_ID to the name of your Google Cloud project:

$ PROJECT_ID=google-cloud-project
$ gcloud projects add-iam-policy-binding ${PROJECT_ID?} \
   --member="serviceAccount:teleport-discovery-kubernetes@${PROJECT_ID?}.iam.gserviceaccount.com" \
   --role="projects/${PROJECT_ID?}/roles/GKEKubernetesAutoDisc"
$ gcloud projects add-iam-policy-binding ${PROJECT_ID?} \
   --member="serviceAccount:teleport-discovery-kubernetes@${PROJECT_ID?}.iam.gserviceaccount.com" \
   --role="projects/${PROJECT_ID?}/roles/GKEAccessManager"
Deploying the Kubernetes Service and Discovery Service separately?

Create a service account for each service:

$ gcloud iam service-accounts create teleport-discovery-service \
  --description="Teleport Discovery Service" \
  --display-name="teleport-discovery-service"
$ gcloud iam service-accounts create teleport-kubernetes-service \
  --description="Teleport Kubernetes Service" \
  --display-name="teleport-kubernetes-service"

Grant the roles you defined earlier to your service account, assigning PROJECT_ID to the name of your Google Cloud project:

$ PROJECT_ID=google-cloud-project
$ gcloud projects add-iam-policy-binding ${PROJECT_ID?} \
   --member="serviceAccount:teleport-discovery-service@${PROJECT_ID?}.iam.gserviceaccount.com" \
   --role="projects/${PROJECT_ID?}/roles/GKEKubernetesAutoDisc"
$ gcloud projects add-iam-policy-binding ${PROJECT_ID?} \
   --member="serviceAccount:teleport-kubernetes-service@${PROJECT_ID?}.iam.gserviceaccount.com" \
   --role="projects/${PROJECT_ID?}/roles/GKEAccessManager"

Retrieve credentials for your Teleport services​

Now that you have created a Google Cloud service account and attached roles to it, associate your service account with the Teleport Kubernetes Service and Discovery Service.

The process is different depending on whether you are deploying the Teleport Kubernetes Service and Discovery Service on Google Cloud or some other way (e.g., via Amazon EC2 or on a local network).

Stop your VM so you can attach your service account to it:

$ gcloud compute instances stop vm-name --zone=google-cloud-region

Attach your service account to the instance, assigning the name of your VM to vm-name and the name of your Google Cloud region to google-cloud-region:

$ gcloud compute instances set-service-account vm-name \
   --service-account teleport-discovery-kubernetes@${PROJECT_ID?}.iam.gserviceaccount.com \
   --zone google-cloud-region \
   --scopes=cloud-platform
Running the Kubernetes and Discovery Services separately?

Stop each VM you plan to use to run the Teleport Kubernetes Service and Discovery Service.

Attach the teleport-kubernetes-service service account to the VM running the Kubernetes Service:

$ gcloud compute instances set-service-account ${VM1_NAME?} \
   --service-account teleport-kubernetes-service@${PROJECT_ID?}.iam.gserviceaccount.com \
   --zone google-cloud-region \
   --scopes=cloud-platform

Attach the teleport-discovery-service service account to the VM running the Discovery Service:

$ gcloud compute instances set-service-account ${VM2_NAME?} \
   --service-account teleport-discovery-service@${PROJECT_ID?}.iam.gserviceaccount.com \
   --zone google-cloud-region \
   --scopes=cloud-platform
warning

You must use the scopes flag in the gcloud compute instances set-service-account command. Otherwise, your Google Cloud VM will fail to obtain the required authorization to access the GKE API.

Once you have attached the service account, restart your VM:

$ gcloud compute instances start vm-name --zone google-cloud-region

Step 2/3. Configure Teleport to discover GKE clusters​

Now that you have created a service account that can discover GKE clusters and a cluster role that can manage access, configure the Teleport Discovery Service to detect GKE clusters and the Kubernetes Service to proxy user traffic.

Install Teleport​

Install Teleport on the host you are using to run the Kubernetes Service and Discovery Service:

Select an edition, then follow the instructions for that edition to install Teleport.

The following command updates the repository for the package manager on the local operating system and installs the provided Teleport version:

$ curl https://cdn.teleport.dev/install-v14.3.33.sh | bash -s 14.3.33

Create a join token​

The Teleport Discovery Service and Kubernetes Service require an authentication token in order to to join the cluster. Generate one by running the following tctl command:

$ tctl tokens add --type=discovery,kube --format=text
abcd123-insecure-do-not-use-this

Copy the token (e.g., abcd123-insecure-do-not-use-this above) and save the token in /tmp/token on the machine that will run the Discovery Service and Kubernetes Service, for example:

$ echo abcd123-insecure-do-not-use-this | sudo tee /tmp/token
# abcd123-insecure-do-not-use-this
Running the Kubernetes and Discovery Services separately?

Generate separate tokens for the Kubernetes Service and Discovery Service by running the following tctl commands:

$ tctl tokens add --type=discovery --format=text
# efgh456-insecure-do-not-use-this
$ tctl tokens add --type=kube --format=text
# ijkl789-insecure-do-not-use-this

Copy each token (e.g., efgh456-insecure-do-not-use-this and ijkl789-insecure-do-not-use-this above) and save it in /tmp/token on the machine that will run the appropriate service.

Configure the Kubernetes Service and Discovery Service​

On the host running the Kubernetes Service and Discovery Service, create a Teleport configuration file with the following content at /etc/teleport.yaml:

warning

Discovery Service exposes a configuration parameter - discovery_service.discovery_group - that allows you to group discovered resources into different sets. This parameter is used to prevent Discovery Agents watching different sets of cloud resources from colliding against each other and deleting resources created by another services.

When running multiple Discovery Services, you must ensure that each service is configured with the same discovery_group value if they are watching the same cloud resources or a different value if they are watching different cloud resources.

It is possible to run a mix of configurations in the same Teleport cluster meaning that some Discovery Services can be configured to watch the same cloud resources while others watch different resources. As an example, a 4-agent high availability configuration analyzing data from two different cloud accounts would run with the following configuration.

  • 2 Discovery Services configured with discovery_group: "prod" polling data from Production account.
  • 2 Discovery Services configured with discovery_group: "staging" polling data from Staging account.
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
discovery_service:
  enabled: "yes"
  discovery_group: "gke-myproject"
  gcp:
    - types: ["gke"]
      locations: ["*"]
      project_ids: ["myproject"] # replace with my project ID
      tags:
        "*" : "*"
kubernetes_service:
  enabled: "yes"
  resources:
  - labels:
      "*": "*"
Running the Kubernetes Service and Discovery Service on separate hosts?

Follow the instructions in this section with two configuration files. The configuration file you will save at /etc/teleport.yaml on the Kubernetes Service host will include the following:

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"
  resources:
  - labels:
      "*": "*"

On the Discovery Service host, the file will include the following:

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
discovery_service:
  enabled: "yes"
  gcp:
    - types: ["gke"]
      locations: ["*"]
      project_ids: ["myproject"] # replace with my project ID
      tags:
        "*" : "*"

Edit this configuration for your environment as explained below.

proxy_server​

Replace teleport.example.com:443 with the host and port of your Teleport Proxy Service (e.g., mytenant.teleport.sh:443 for a Teleport Cloud tenant).

discovery_service.gcp​

Each item in discovery_service.gcp is a matcher for Kubernetes clusters running on GKE. The Discovery Service periodically executes a request to the Google Cloud API based on each matcher to list GKE clusters. In this case, we have declared a single matcher.

Each matcher searches for clusters that match all properties of the matcher, i.e., that belong to the specified locations and projects and have the specified tags. The Discovery Service registers GKE clusters that match any configured matcher.

This means that if you declare the following two matchers, the Discovery Service will register clusters in project myproj-dev running in us-east1, as well as clusters in project myproj-prod running in us-east2, but not clusters in myproj-dev running in us-east2:

discovery_service:
  enabled: "yes"
  gcp:
    - types: ["gke"]
      locations: ["us-east1"]
      project_ids: ["myproj-dev"]
      tags:
        "*" : "*"
    - types: ["gke"]
      locations: ["us-east2"]
      project_ids: ["myproj-prod"]
      tags:
        "*" : "*"

discovery_service.gcp[0].types​

Each matcher's types field must be set to an array with a single string value, gke.

discovery_service.gcp[0].project_ids​

In your matcher, replace myproject with the ID of your Google Cloud project.

Ensure that the project_ids field follows these rules:

  • It must include at least one value.
  • It must not combine the wildcard character (*) with other values.
Examples of valid configurations​
  • ["p1", "p2"]
  • ["*"]
  • ["p1"]
Example of an invalid configuration​
  • ["p1", "*"]

discovery_service.gcp[0].locations​

Each matcher's locations field contains an array of Google Cloud region or zone names that the matcher will search for GKE clusters. The wildcard character, *, configures the matcher to search all locations.

discovery_service.gcp[0].tags​

Like locations, tags consists of a map where each key is a string that represents the key of a tag, and each value is either a single string or an array of strings, representing one tag value or a list of tag values.

A wildcard key or value matches any tag key or value in your Google Cloud account. If you include another value, the matcher will match all GKE clusters with the provided tag.

Start the Kubernetes Service and Discovery Service​

On the host where you will run the Kubernetes Service, execute the following command, depending on:

  • Whether you installed Teleport using a package manager or via a TAR archive
  • Whether you are running the Discovery and Kubernetes Service on Google Cloud or another platform

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

$ sudo systemctl start teleport

Step 3/3. Connect to your GKE 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:

$ kubectl config current-context
Using the wrong context?

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: v6
spec:
  allow:
    kubernetes_labels:
      '*': '*'
    kubernetes_resources:
      - kind: 'pod'
        namespace: '*'
        name: '*'
    kubernetes_groups:
    - viewers
    kubernetes_users:
    # Replace USER with the Kubernetes user for your current context.
    - USER
  deny: {}

Apply your changes:

$ tctl create -f kube-access.yaml

Assign the kube-access role to your Teleport user by running the appropriate commands for your authentication provider:

  1. Retrieve your local user's configuration resource:

    $ tctl get users/$(tsh status -f json | jq -r '.active.username') > out.yaml

  2. Edit out.yaml, adding kube-access to the list of existing roles:

      roles:
       - access
       - auditor
       - editor
    +  - kube-access

  3. Apply your changes:

    $ tctl create -f out.yaml

  4. Sign out of the Teleport cluster and sign in again to assume the new role.

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.

Access your cluster​

When you ran the Discovery Service, it discovered your GKE cluster and registered the cluster with Teleport. You can confirm this by running the following tctl command:

$ tctl get kube_clusters
kind: kube_cluster
metadata:
  description: GKE cluster "mycluster-gke" in us-east1
  id: 0000000000000000000
  labels:
    location: us-east1
    project-id: myproject
    teleport.dev/cloud: GCP
    teleport.dev/origin: cloud
  name: mycluster-gke
spec:
  aws: {}
  azure: {}
version: v3

Run the following command to list the Kubernetes clusters that your Teleport user has access to. The list should now include your GKE cluster:

$ tsh kube ls
Kube Cluster Name   Labels                                                                                                   Selected
------------------- -------------------------------------------------------------------------------------------------------- --------
mycluster-gke location=us-east1 project-id=myproject teleport.dev/cloud=GCP teleport.dev/origin=cloud

Log in to your cluster, replacing mycluster-gke with the name of a cluster you listed previously:

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

As you can see, Teleport GKE Auto-Discovery enabled you to access a GKE cluster in your Google Cloud account without requiring you to register that cluster manually within Teleport. When you create or remove clusters in GKE, Teleport will update its state to reflect the available clusters in your account.

Troubleshooting​

Discovery Service​

To check if the Discovery Service is working correctly, you can check if any Kubernetes clusters have been discovered. To do this, you can use the tctl get kube_cluster command and inspect if the expected clusters have already been imported into Teleport.

If some clusters do not appear in the list, check if the filtering labels match the missing cluster tags or look into the service logs for permission errors.

Kubernetes Service​

If the tctl get kube_cluster command returns the discovered clusters, but the tsh kube ls command does not include them, check that you have set the kubernetes_service.resources section correctly.

kubernetes_service:
  enabled: "yes"
  resources:
  - tags:
      "env": "prod"

If the section is correctly configured, but clusters still do not appear or return authentication errors, please check if permissions have been correctly configured in your target cluster or that you have the correct permissions to list Kubernetes clusters in Teleport.