Minimize the admission of containers wishing to share the host IPC namespace

Description:

Do not generally permit containers to be run with the 'hostIPC' flag set to true.

Rationale:

A container running in the host's IPC namespace can use IPC to interact with processes outside the container.

There should be at least one admission control policy defined which does not permit containers to share the host IPC namespace.

If you need to run containers which require hostIPC, this should be defined in a separate policy and you should carefully check to ensure that only limited service accounts and users are given permission to use that policy.

Pods defined with 'spec.hostIPC: true' will not be permitted unless they are run under a specific policy.

Add policies to each namespace in the cluster which has user workloads to restrict the admission of 'hostIPC' containers.