runtime-spec/config-zos.md

z/OS Container Configuration

This document describes the schema for the z/OS-specific section of the container configuration. The z/OS container specification uses z/OS UNIX kernel features like namespaces and filesystem jails to fulfill the spec.

Applications expecting a z/OS environment will very likely expect these file paths to be set up correctly.

The following filesystems SHOULD be made available in each container's filesystem:

Path	Type
/proc	[proc][]

Namespaces

A namespace wraps a global system resource in an abstraction that makes it appear to the processes within the namespace that they have their own isolated instance of the global resource. Changes to the global resource are visible to other processes that are members of the namespace, but are invisible to other processes. For more information, see https://www.ibm.com/docs/zos/latest?topic=planning-namespaces-zos-unix.

Namespaces are specified as an array of entries inside the namespaces root field. The following parameters can be specified to set up namespaces:

• type (string, REQUIRED) - namespace type. The following namespace types SHOULD be supported:

  • pid processes inside the container will only be able to see other processes inside the same container or inside the same pid namespace.
  • mount the container will have an isolated mount table.
  • ipc processes inside the container will only be able to communicate to other processes inside the same container via system level IPC.
  • uts the container will be able to have its own hostname and domain name.

• path (string, OPTIONAL) - namespace file. This value MUST be an absolute path in the runtime mount namespace. The runtime MUST place the container process in the namespace associated with that path. The runtime MUST generate an error if path is not associated with a namespace of type type.

  If path is not specified, the runtime MUST create a new container namespace of type type.

If a namespace type is not specified in the namespaces array, the container MUST inherit the runtime namespace of that type. If a namespaces field contains duplicated namespaces with same type, the runtime MUST generate an error.

Example

"namespaces": [
    {
        "type": "pid",
        "path": "/proc/1234/ns/pid"
    },
    {
        "type": "mount"
    },
    {
        "type": "ipc"
    },
    {
        "type": "uts"
    }
]