Description of problem:
running podman in rootless mode (as user) with ubi8-init (systemd inside container) does not work.
"The issue seems to be in podman setting a default pids limit, but the pids controller is not enabled by systemd for unprivileged users"

Version-Release number of selected component (if applicable):
$ podman version
Version: 2.0.5
API Version: 1
Go Version: go1.14.7
Built: Wed Sep 23 18:18:02 2020
OS/Arch: linux/amd64

$ lsb_release -a
LSB Version: :core-4.1-amd64:core-4.1-noarch
Distributor ID: RedHatEnterprise
Description: Red Hat Enterprise Linux release 8.3 (Ootpa)
Release: 8.3
Codename: Ootpa

How reproducible:
1) enable cgroup2: add cgroup_no_v1=all systemd.unified_cgroup_hierarchy=1 to kernel parameter + reboot
2) set subuid / subgid for the user to be running podman rootless
3) sysctl increase namespaces: /proc/sys/user/max_user_namespaces
4) run podman as user in question: podman run --name=ubi-init-test1 --cgroup-manager=systemd -it --rm --systemd=true ubi8-init

Steps to Reproduce:
1. enable cgroup2 + set subuid/subguid + set namespaces
2. reboot
3. podman as user in question: podman run --name=ubi-init-test1 --cgroup-manager=systemd -it --rm --systemd=true ubi8-init

Actual results:
Error: writing file `/sys/fs/cgroup/user.slice/user-992.slice/user@992.service/cgroup.subtree_control`: No such file or directory: OCI runtime command not found error

ls -l /sys/fs/cgroup/user.slice/user-992.slice/user@992.service/cgroup.subtree_control
rw-rr-. 1 gitlab-runner gitlab-runner 0 Nov 13 14:57 /sys/fs/cgroup/user.slice/user-992.slice/user@992.service/cgroup.subtree_control

Expected results:
working container / running container

Additional info:
we also added the following, but it seems to have no effect/not being honored:

$ cat /etc/systemd/system/user@.service.d/delegate.conf
[Service]
Delegate=memory pids

-> delegation seems to not work

it can be made to work if the active session scope is chowned (by root) to the user id in question
example:
/usr/bin/chown -R 992 /sys/fs/cgroup/user.slice/user-992.slice/session-225.scope

podman info
host:
arch: amd64
buildahVersion: 1.15.1
cgroupVersion: v2
conmon:
package: conmon-2.0.20-2.module+el8.3.0+8221+97165c3f.x86_64
path: /usr/bin/conmon
version: 'conmon version 2.0.20, commit: 77ce9fd1e61ea89bd6cdc621b07446dd9e80e5b6'
cpus: 2
distribution:
distribution: '"rhel"'
version: "8.3"
eventLogger: file
hostname: vie02s807
idMappings:
gidmap:

• container_id: 0
  host_id: 987
  size: 1
• container_id: 1
  host_id: 100000
  size: 65536
  uidmap:
• container_id: 0
  host_id: 992
  size: 1
• container_id: 1
  host_id: 100000
  size: 65536
  kernel: 4.18.0-240.1.1.el8_3.x86_64
  linkmode: dynamic
  memFree: 182124544
  memTotal: 4118835200
  ociRuntime:
  name: crun
  package: crun-0.14.1-2.module+el8.3.0+8221+97165c3f.x86_64
  path: /usr/bin/crun
  version: |-
  crun version 0.14.1
  commit: 598ea5e192ca12d4f6378217d3ab1415efeddefa
  spec: 1.0.0
  +SYSTEMD +SELINUX +APPARMOR +CAP +SECCOMP +EBPF +YAJL
  os: linux
  remoteSocket:
  path: /run/user/992/podman/podman.sock
  rootless: true
  slirp4netns:
  executable: /usr/bin/slirp4netns
  package: slirp4netns-1.1.4-2.module+el8.3.0+8221+97165c3f.x86_64
  version: |-
  slirp4netns version 1.1.4
  commit: b66ffa8e262507e37fca689822d23430f3357fe8
  libslirp: 4.3.1
  SLIRP_CONFIG_VERSION_MAX: 3
  swapFree: 1072676864
  swapTotal: 1073737728
  uptime: 46h 9m 29.12s (Approximately 1.92 days)
  registries:
  search:
• registry.access.redhat.com
• registry.redhat.io
• docker.io
• registry.gitlab.com
  store:
  configFile: /home/gitlab-runner/.config/containers/storage.conf
  containerStore:
  number: 0
  paused: 0
  running: 0
  stopped: 0
  graphDriverName: overlay
  graphOptions:
  overlay.mount_program:
  Executable: /usr/bin/fuse-overlayfs
  Package: fuse-overlayfs-1.1.2-3.module+el8.3.0+8221+97165c3f.x86_64
  Version: |-
  fuse-overlayfs: version 1.1.0
  FUSE library version 3.2.1
  using FUSE kernel interface version 7.26
  graphRoot: /home/gitlab-runner/.local/share/containers/storage
  graphStatus:
  Backing Filesystem: extfs
  Native Overlay Diff: "false"
  Supports d_type: "true"
  Using metacopy: "false"
  imageStore:
  number: 2
  runRoot: /run/user/992/containers
  volumePath: /home/gitlab-runner/.local/share/containers/storage/volumes
  version:
  APIVersion: 1
  Built: 1600877882
  BuiltTime: Wed Sep 23 18:18:02 2020
  GitCommit: ""
  GoVersion: go1.14.7
  OsArch: linux/amd64
  Version: 2.0.5