Target a specific container

A telepresence replace or telepresence ingest will always target a specific container, and the --container flag is mandatory when the workload has more than one container.

A telepresence intercept will ultimately target a specific port within a container. The port is usually determined by examining the relationship between the service's targetPort and the container's containerPort.

In certain scenarios, the container owning the intercepted port differs from the container the intercept targets. This container's sole purpose is to route traffic from the service to the intended container, often using a direct localhost connection. Use the --container flag with the intercept in these scenarios.

No intercept

Consider the following scenario:

Standard Intercept

During a replace, the Telepresence traffic-agent will redirect all traffic intended for the replaced container to the workstation. It will also make the environment and mounts for the Nginx container available, because it is considered to be the one targeted by the intercept.

During an intercept, the Telepresence traffic-agent will redirect the http port to the workstation. It will also make the environment and mounts for the Nginx container available, because it is considered to be the one targeted by the intercept.

Terminal

$ telepresence intercept myservice --port http

Intercept With --container

The --container <name> intercept flag is useful when the objective is to work with the App container locally. While this option doesn't influence the port selection, it guarantees that the environment variables and mounts propagated to the workstation originate from the specified container.

Terminal

$ telepresence intercept myservice --port http --container app