<p>On this page in the Kubernetes docs <a href="https://github.com/GoogleCloudPlatform/kubernetes/blob/master/docs/user-guide/pods.md" rel="noreferrer">Pods</a>, it states</p>

<blockquote>
  <p>The context of the pod can be defined as the conjunction of several Linux namespaces:</p>
  
  <p>PID namespace (applications within the pod can see each other's processes)
  network namespace (applications within the pod have access to the same IP and port space)</p>
  
  <p>IPC namespace (applications within the pod can use SystemV IPC or POSIX message queues to communicate)</p>
  
  <p>UTS namespace (applications within the pod share a hostname)</p>
</blockquote>

<p>However, it then says that</p>

<blockquote>
  <p>In terms of Docker constructs, a pod consists of a colocated group of Docker containers with shared volumes. PID namespace sharing is not yet implemented with Docker.</p>
</blockquote>

<p>So does this mean that pods cannot see processes in other containers or perform any kind of IPC between containers running in the same pod?  How would I send a signal to a process running in another pod?</p>

<p>Yeah, we wish that they could share the PID namespace, but as you say, it is not currently supported by Docker.  Once we have support in Docker, we will rapidly add it to Kubernetes.</p>

<p>This means that you can't use signal to signal other processes in the Pod.</p>

<p>You can, however, use IPC mechanisms like pipes and shared memory.</p>
