Cluster-side configuration

For the most part, Telepresence doesn't require any special configuration in the cluster and can be used right away in any cluster (as long as the user has adequate RBAC permissions and the cluster's server version is 1.19.0 or higher).

Helm Chart configuration

Some cluster specific configuration can be provided when installing or upgrading the Telepresence cluster installation using Helm. Once installed, the Telepresence client will configure itself from values that it receives when connecting to the Traffic manager.

See the Helm chart README for a full list of available configuration settings.

Values

To add configuration, create a yaml file with the configuration values and then use it executing telepresence helm install [--upgrade] --values <values yaml>

Client Configuration

It is possible for the Traffic Manager to automatically push config to all connecting clients. To learn more about this, please see the client config docs

Agent Configuration

The agent structure of the Helm chart configures the behavior of the Telepresence agents.

Application Protocol Selection

The agent.appProtocolStrategy is relevant when using personal intercepts and controls how telepresence selects the application protocol to use when intercepting a service that has no service.ports.appProtocol declared. The port's appProtocol is always trusted if it is present. Valid values are:

When portName is used, Telepresence will determine the protocol by the name of the port: <protocol>[-suffix]. The following protocols are recognized:

Envoy Configuration

The agent.envoy structure contains three values:

Image Configuration

The agent.image structure contains the following values:

Log level

The agent.LogLevel controls the log level of the traffic-agent. See Log Levels for more info.

Resources

The agent.resources and agent.initResources will be used as the resources element when injecting traffic-agents and init-containers.

TLS

In this example, other applications in the cluster expect to speak TLS to your intercepted application (perhaps you're using a service-mesh that does mTLS).

In order to use --mechanism=http (or any features that imply --mechanism=http) you need to tell Telepresence about the TLS certificates in use.

Tell Telepresence about the certificates in use by adjusting your workload's Pod template to set a couple of annotations on the intercepted Pods:

• The getambassador.io/inject-terminating-tls-secret annotation (optional) names the Kubernetes Secret that contains the TLS server certificate to use for decrypting and responding to incoming requests.

  When Telepresence modifies the Service and workload port definitions to point at the Telepresence Agent sidecar's port instead of your application's actual port, the sidecar will use this certificate to terminate TLS.

• The getambassador.io/inject-originating-tls-secret annotation (optional) names the Kubernetes Secret that contains the TLS client certificate to use for communicating with your application.

  You will need to set this if your application expects incoming requests to speak TLS (for example, your code expects to handle mTLS itself instead of letting a service-mesh sidecar handle mTLS for it, or the port definition that Telepresence modified pointed at the service-mesh sidecar instead of at your application).

  If you do set this, you should to set it to the same client certificate Secret that you configure the Ambassador Edge Stack to use for mTLS.

It is only possible to refer to a Secret that is in the same Namespace as the Pod. The Secret will be mounted into the traffic agent's container.

Telepresence understands type: kubernetes.io/tls Secrets and type: istio.io/key-and-cert Secrets; as well as type: Opaque Secrets that it detects to be formatted as one of those types.

Air-gapped cluster

If your cluster is on an isolated network such that it cannot communicate with Ambassador Cloud, then some additional configuration is required to acquire a license key in order to use personal intercepts. A buisness or enterprise plan is required to generate a license.

Create a license

1. Log in and Go to the teams setting page in Ambassador Cloud and select Telepresence Licenses for the team you want to create the license for.

2. Generate a new license (if one doesn't already exist) by clicking Generate New License.

3. You will be prompted for your Cluster ID. Ensure your kubeconfig context is using the cluster you want to create a license for then run this command to generate the Cluster ID:

4. Click Generate API Key to finish generating the license.

5. On the licenses page, download the license file associated with your cluster.

Add license to cluster

There are two separate ways you can add the license to your cluster: manually creating and deploying the license secret or having the helm chart manage the secret

You only need to do one of the two options.

Manual deploy of license secret

1. Use this command to generate a Kubernetes Secret config using the license file:

2. Save the output as a YAML file and apply it to your cluster with kubectl.

3. When deploying the traffic-manager chart, you must add the additional values when running helm install by putting the following into a file (for the example we'll assume it's called license-values.yaml)

4. Install the helm chart into the cluster

5. Ensure that you have the docker image for the Smart Agent (datawire/ambassador-telepresence-agent:1.11.0) pulled and in a registry your cluster can pull from.

6. Have users use the images config key keys so telepresence uses the aforementioned image for their agent.

Helm chart manages the secret

1. Get the jwt token from the downloaded license file

2. Create the following values file, substituting your real jwt token in for the one used in the example below. (for this example we'll assume the following is placed in a file called license-values.yaml)

3. Install the helm chart into the cluster

Users will now be able to use preview intercepts with the --preview-url=false flag. Even with the license key, preview URLs cannot be used without enabling direct communication with Ambassador Cloud, as Ambassador Cloud is essential to their operation.

If using Helm to install the server-side components, see the chart's README to learn how to configure the image registry and license secret.

Mutating Webhook

Telepresence uses a Mutating Webhook to inject the Traffic Agent sidecar container and update the port definitions. This means that an intercepted workload (Deployment, StatefulSet, ReplicaSet) will remain untouched and in sync as far as GitOps workflows (such as ArgoCD) are concerned.

The injection will happen on demand the first time an attempt is made to intercept the workload.

If you want to prevent that the injection ever happens, simply add the telepresence.getambassador.io/inject-traffic-agent: disabled annotation to your workload template's annotations:

Service Name and Port Annotations

Telepresence will automatically find all services and all ports that will connect to a workload and make them available for an intercept, but you can explicitly define that only one service and/or port can be intercepted.

Ignore Certain Volume Mounts

An annotation telepresence.getambassador.io/inject-ignore-volume-mounts can be used to make the injector ignore certain volume mounts denoted by a comma-separated string. The specified volume mounts from the original container will not be appended to the agent sidecar container.

Note on Numeric Ports

If the targetPort of your intercepted service is pointing at a port number, in addition to injecting the Traffic Agent sidecar, Telepresence will also inject an initContainer that will reconfigure the pod's firewall rules to redirect traffic to the Traffic Agent.

If you need to use numeric ports without the aforementioned capabilities, you can manually install the agent

For example, the following service is using a numeric port, so Telepresence would inject an initContainer into it:

Excluding Envrionment Variables

If your pod contains sensitive variables like a database password, or third party API Key, you may want to exclude those from being propagated through an intercept. Telepresence allows you to configure this through a ConfigMap that is then read and removes the sensitive variables.

This can be done in two ways:

When installing your traffic-manager through helm you can use the --set flag and pass a comma separated list of variables:

telepresence helm install --set intercept.environment.excluded="{DATABASE_PASSWORD,API_KEY}"

This also applies when upgrading:

telepresence helm upgrade --set intercept.environment.excluded="{DATABASE_PASSWORD,API_KEY}"

Once this is completed, the environment variables will no longer be in the environment file created by an Intercept.

The other way to complete this is in your custom values.yaml. Customizing your traffic-manager through a values file can be viewed here.

You can exclude any number of variables, they just need to match the key of the variable within a pod to be excluded.