Unable to set shm-size for /dev/shm shared by a pod

[dtmdl]

Is this a BUG REPORT or FEATURE REQUEST? (leave only one on its own line)
/kind feature

Description
I am trying to increase the size of the shared /dev/shm attached to the containers in a pod.

There is no --shm-size option to podman pod create and the --shm-size option for podman run is rejected when the container is being added to a pod with --share ipc enabled (as is the default).

Steps to reproduce the issue:

1. podman pod create --name shm-pod --shm-size 256M

2. podman pod create --name shm-pod

3. podman run --shm-size 256M --rm -t --pod shm-pod alpine mount | grep shm

4. podman run --rm -t --pod shm-pod alpine mount | grep shm

Describe the results you received:

1. podman pod create with --shm-size

Error: unknown flag: --shm-size
See 'podman pod create --help'

2. podman pod create

b2bcda49a5f182b1d9694e1577a6ffe1ce3dffb8bdce3c7e6d5b16004ae67440

3. podman run with --shm-size

Error: invalid config provided: cannot set shmsize when running in the host IPC Namespace

4. podman run

shm on /dev/shm type tmpfs (rw,context="system_u:object_r:container_file_t:s0:c825,c880",nosuid,nodev,noexec,relatime,size=64000k,uid=1001,gid=1001,inode64)

Describe the results you expected:

I would like some way to specify --shm-size for a pod with --share ipc.

Additional information you deem important (e.g. issue happens only occasionally):

Using pod create --share to un-share the ipc namespace (which is awkward, as it requires listing the default shared namespaces excluding ipc) does allow specifying --shm-size on the podman run command, but then /dev/shm is not shared.

Output of podman version:

Client:       Podman Engine
Version:      4.0.2
API Version:  4.0.2
Go Version:   go1.17.7

Built:      Thu May 19 19:18:11 2022
OS/Arch:    linux/amd64

[Luap99]

@cdoern PTAL

[rhatdan]

@cdoern this needs to be added to podman pod create.

[cdoern]

ok, I will work on this today