Podman : Use by common users2025/04/22

	It's possible to use Podman containers by common users.
[1]	By default, sub UID/GID that are used on user name spaces are assigned to run containers.

# default name spaces number

root@dlp:~#

cat /proc/sys/user/max_user_namespaces

61583

# sub UID/GID mapping file
# 100000 to 165535 (100000 + 65536 - 1) UID are used for running processes in containers on [ubuntu] user

root@dlp:~#

cat /etc/subuid

ubuntu:100000:65536
root@dlp:~#

cat /etc/subgid

ubuntu:100000:65536

# when added new users, sub UID/GID are also added
# n=0, n++
# [start UID/GID = 100000 + (65536 * n)]
# [end UID/GID = (start UID/GID) + 65536 - 1]

root@dlp:~#

useradd plucky

root@dlp:~#

useradd puffin

root@dlp:~#

cat /etc/subgid /etc/subgid

ubuntu:100000:65536
plucky:165536:65536
puffin:231072:65536
ubuntu:100000:65536
plucky:165536:65536
puffin:231072:65536

[2]	It's possible to run [podman] by common users.

ubuntu@dlp:~$

podman pull ubuntu

ubuntu@dlp:~$

podman images

REPOSITORY                TAG         IMAGE ID      CREATED      SIZE
docker.io/library/ubuntu  latest      602eb6fb314b  13 days ago  80.6 MB

ubuntu@dlp:~$

podman run ubuntu echo "run rootless containers"

run rootless containers

# containers related files are located under the [$HOME/.local] directory

ubuntu@dlp:~$

ll ~/.local/share/containers/storage

total 164
drwx------ 9 ubuntu ubuntu   4096 Apr 22 00:50 ./
drwx------ 4 ubuntu ubuntu   4096 Apr 22 00:50 ../
-rw-r--r-- 1 ubuntu ubuntu 122880 Apr 22 00:50 db.sql
-rw-r--r-- 1 ubuntu ubuntu      8 Apr 22 00:50 defaultNetworkBackend
drwx------ 2 ubuntu ubuntu   4096 Apr 22 00:50 libpod/
drwx------ 2 ubuntu ubuntu   4096 Apr 22 00:50 networks/
drwx------ 5 ubuntu ubuntu   4096 Apr 22 00:50 overlay/
drwx------ 3 ubuntu ubuntu   4096 Apr 22 00:50 overlay-containers/
drwx------ 3 ubuntu ubuntu   4096 Apr 22 00:50 overlay-images/
drwx------ 2 ubuntu ubuntu   4096 Apr 22 00:50 overlay-layers/
-rw-r--r-- 1 ubuntu ubuntu     64 Apr 22 00:50 storage.lock
-rw-r--r-- 1 ubuntu ubuntu      0 Apr 22 00:50 userns.lock
drwx------ 2 ubuntu ubuntu   4096 Apr 22 00:50 volumes/

# possible to create Pods

ubuntu@dlp:~$

podman pod create -p 8081:80 -n test-pod

ubuntu@dlp:~$

podman pod ls

POD ID        NAME        STATUS      CREATED        INFRA ID      # OF CONTAINERS
fe0ea39f1400  test-pod    Created     3 seconds ago  211de5a73ebc  1

# for port mapping,
# it's impossible to use less than [1024] ports on Host machine by common users
# possible to use over [1024] ports

ubuntu@dlp:~$

podman run -itd -p 1023:80 ubuntu /bin/bash

Error: rootlessport cannot expose privileged port 1023, you can add 'net.ipv4.ip_unprivileged_port_start=1023' to /etc/sysctl.conf (currently 1024), or choose a larger port number (>= 1024): listen tcp 0.0.0.0:1023: bind: permission denied

ubuntu@dlp:~$

podman run -itd -p 1024:80 ubuntu /bin/bash

ubuntu@dlp:~$

podman ps

CONTAINER ID  IMAGE                            COMMAND     CREATED        STATUS        PORTS                 NAMES
99515000c3b3  docker.io/library/ubuntu:latest  /bin/bash   3 seconds ago  Up 4 seconds  0.0.0.0:1024->80/tcp  infallible_maxwell

Matched Content