rootless_tutorial: modernize it please

[Crer-lu]

Issue Description

When i am reading this doc cgroup V2 support
i cant run the command

Steps to reproduce the issue

Steps to reproduce the issue

1. podman --runtime crun

Describe the results you received

Error: missing command 'podman COMMAND'
Try 'podman --help' for more information.

Describe the results you expected

as docs suggested

podman info output

host:
  arch: amd64
  buildahVersion: 1.23.1
  cgroupControllers:
  - cpuset
  - cpu
  - io
  - memory
  - pids
  cgroupManager: systemd
  cgroupVersion: v2
  conmon:
    package: 'conmon: /usr/libexec/podman/conmon'
    path: /usr/libexec/podman/conmon
    version: 'conmon version 2.1.2, commit: '
  cpus: 2
  distribution:
    codename: jammy
    distribution: ubuntu
    version: "22.04"
  eventLogger: journald
  hostname: VM-4-17-ubuntu
  idMappings:
    gidmap:
    - container_id: 0
      host_id: 1002
      size: 1
    - container_id: 1
      host_id: 231072
      size: 65536
    uidmap:
    - container_id: 0
      host_id: 1002
      size: 1
    - container_id: 1
      host_id: 231072
      size: 65536
  kernel: 5.15.0-86-generic
  linkmode: dynamic
  logDriver: journald
  memFree: 153522176
  memTotal: 2059169792
  ociRuntime:
    name: crun
    package: 'crun: /usr/bin/crun'
    path: /usr/bin/crun
    version: |-
      crun version UNKNOWN
      commit: ea1fe3938eefa14eb707f1d22adff4db670645d6
      spec: 1.0.0
      +SYSTEMD +SELINUX +APPARMOR +CAP +SECCOMP +EBPF +CRIU +YAJL
  os: linux
  remoteSocket:
    path: /run/user/1002/podman/podman.sock
  security:
    apparmorEnabled: false
    capabilities: CAP_CHOWN,CAP_DAC_OVERRIDE,CAP_FOWNER,CAP_FSETID,CAP_KILL,CAP_NET_BIND_SERVICE,CAP_SETFCAP,CAP_SETGID,CAP_SETPCAP,CAP_SETUID,CAP_SYS_CHROOT
    rootless: true
    seccompEnabled: true
    seccompProfilePath: /usr/share/containers/seccomp.json
    selinuxEnabled: false
  serviceIsRemote: false
  slirp4netns:
    executable: /usr/bin/slirp4netns
    package: 'slirp4netns: /usr/bin/slirp4netns'
    version: |-
      slirp4netns version 1.1.8
      commit: unknown
      libslirp: 4.3.1-git
      SLIRP_CONFIG_VERSION_MAX: 3
      libseccomp: 2.5.3
  swapFree: 0
  swapTotal: 0
  uptime: 1h 7m 33.13s (Approximately 0.04 days)
plugins:
  log:
  - k8s-file
  - none
  - journald
  network:
  - bridge
  - macvlan
  volume:
  - local
registries: {}
store:
  configFile: /home/lu/.config/containers/storage.conf
  containerStore:
    number: 0
    paused: 0
    running: 0
    stopped: 0
  graphDriverName: overlay
  graphOptions: {}
  graphRoot: /home/lu/.local/share/containers/storage
  graphStatus:
    Backing Filesystem: extfs
    Native Overlay Diff: "true"
    Supports d_type: "true"
    Using metacopy: "false"
  imageStore:
    number: 1
  runRoot: /run/user/1002/containers
  volumePath: /home/lu/.local/share/containers/storage/volumes
version:
  APIVersion: 3.4.4
  Built: 0
  BuiltTime: Thu Jan  1 08:00:00 1970
  GitCommit: ""
  GoVersion: go1.18.1
  OsArch: linux/amd64
  Version: 3.4.4

Podman in a container

No

Privileged Or Rootless

None

Upstream Latest Release

Yes

Additional environment details

Ubuntu 22.04

Additional information

Additional information like issue happens only occasionally or issue happens with a particular architecture or on a particular setting

[rhatdan]

Does podman --runtime crun info work?

The problem is you did not give a command.

[edsantiago]

The full context here is "...by using the --runtime option: podman --runtime crun." It's like saying "...using the -r option: cp -r." You still need to give arguments.

However, in looking at that doc, it is ancient. Cgroups V2 and crun are no longer experimental, fuse-overlayfs >0.76 is a safe assumption, and RHEL7 is ... well, still supported I guess. Let's use this issue as a placeholder for someone to modernize the rootless doc.

[rhatdan]

SGTM

[Crer-lu]

Does podman --runtime crun info work?

The problem is you did not give a command.

thanks, i understand it now!
i just cannot figure out why it doesnt work, but now it is clear
so i think it will be helpful if we modify some content in the doc