Get Started with Kubernetes Application Discovery

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Teleport can automatically detect applications running in your Kubernetes clusters and register them with your Teleport cluster. In this setup, users with Kubernetes-hosted infrastructure can configure secure access to any new applications they deploy with no need for manual intervention beyond the initial setup step.

In this guide, we show you how to enable Kubernetes application auto-discovery.

How it works

The Teleport Discovery Service queries the API server of the Kubernetes cluster in which you want to detect applications, maintaining dynamic app resources to match the Kubernetes services that it detects within the cluster. The Teleport Application Service queries the Teleport Auth Service to fetch app resources, and proxies applications based the dynamically generated configuration.

Prerequisites

• A running Teleport cluster version 17.5.1 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 version >= 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+"}

• 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.

  For example, run the following command, assigning teleport.example.com to the domain name of the Teleport Proxy Service in your cluster and email@example.com to your Teleport username:

  tsh login --proxy=teleport.example.com --user=email@example.com
  tctl status
  Cluster  teleport.example.com
  Version  17.5.1
  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 1/2. Create a join token

Create a join token for a new Teleport Agent that will run the Teleport Kubernetes Service, Application Service, and Discovery Service:

tctl tokens add --type=kube,app,discovery

Enabling the discovery role by default will automatically start the discovery of Kubernetes services and registration of Teleport applications from them. And enabling app role on the chart will start the process of proxying all new Teleport applications created from discovered Kubernetes services.

Step 2/2. Deploy the agent

If you want to install a new Teleport Agent in your Kubernetes cluster, you can use the teleport-kube-agent Helm chart. If you already have a Teleport Agent installed, you can upgrade it to enable the Kubernetes Application Discovery by adding the kube, app, and discovery to roles as shown below.

Install a new agent

Deploy a new Teleport Agent running your configured services by installing the teleport-kube-agent Helm chart, assigning proxy-address to the host and port of your Teleport Proxy Service and token to the join token you created earlier:

helm install teleport-agent teleport/teleport-kube-agent \  --set roles=kube\,app\,discovery \  --set kubeClusterName=main-cluster \  --set proxyAddr=proxy-address \  --set authToken=token \  --create-namespace \  --namespace=teleport

Upgrade an existing agent

If you want to have an existing teleport-kube-agent installation and want to enable Kubernetes App Discovery, you need to update the existing installation role to include kube, app, and discovery roles:

helm upgrade teleport-agent teleport/teleport-kube-agent \  --reuse-values \  --set roles=kube\,app\,discovery \  --set authToken=token \  --namespace=teleport

Troubleshooting

First, make sure that all expected agents for the Teleport Discovery, Application, and Kubernetes Services are running. The token you created for them must have the required roles.

If agents are running, but you don't see expected apps appearing in Teleport, there could be two main reasons:

• The Teleport Discovery Service can't find relevant Kubernetes services.
• The Teleport Application Service can't proxy discovered applications.

Make sure that Kubernetes service account under which the Discovery Service is running has enough permissions to list the cluster's services. Also make sure that labels and namespaces configuration is correct.

For the Application Service, make sure that labels in resources field are defined correctly, specifically that label teleport.dev/kubernetes-cluster matches discovery_group field of the Discovery Service running in the Kubernetes cluster.

Next steps

You can configure the scope of the Discovery Service. For more information, see teleport-kube-agent helm chart documentation.