Fedora 40
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Podman : Use by common users2024/05/03

 
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

63769
# sub UID/GID mapping file
# 524288 to 589823 (524288 + 65536 - 1) UID are used for running processes in containers on [fedora] user

[root@dlp ~]#
cat /etc/subuid

fedora:524288:65536
[root@dlp ~]#
cat /etc/subgid

fedora:524288:65536
# when added new users, sub UID/GID are also added
# n=0, n++
# [start UID/GID = 524288 + (65536 * n)]
# [end UID/GID = (start UID/GID) + 65536 - 1]

[root@dlp ~]#
useradd redhat

[root@dlp ~]#
useradd centos

[root@dlp ~]#
cat /etc/subgid /etc/subgid

fedora:524288:65536
redhat:589824:65536
centos:655360:65536
fedora:524288:65536
redhat:589824:65536
centos:655360:65536
[2] It's possible to run [podman] by common users.
[fedora@dlp ~]$
podman pull fedora

[fedora@dlp ~]$
podman images

REPOSITORY                         TAG         IMAGE ID      CREATED      SIZE
registry.fedoraproject.org/fedora  latest      19f52f582331  3 hours ago  229 MB

[fedora@dlp ~]$
podman run fedora echo "run rootless containers"

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

[fedora@dlp ~]$
ll ~/.local/share/containers/storage

total 128
-rw-r--r--. 1 fedora fedora 122880 May  3 17:33 db.sql
-rw-r--r--. 1 fedora fedora      8 May  3 17:32 defaultNetworkBackend
drwx------. 2 fedora fedora      6 May  3 17:32 libpod
drwx------. 2 fedora fedora     27 May  3 17:32 networks
drwx------. 5 fedora fedora    185 May  3 17:33 overlay
drwx------. 3 fedora fedora    124 May  3 17:33 overlay-containers
drwx------. 3 fedora fedora    116 May  3 17:32 overlay-images
drwx------. 2 fedora fedora    129 May  3 17:33 overlay-layers
-rw-r--r--. 1 fedora fedora     64 May  3 17:33 storage.lock
-rw-r--r--. 1 fedora fedora      0 May  3 17:32 userns.lock

# possible to create Pods

[fedora@dlp ~]$
podman pod create -p 8081:80 -n test-pod

[fedora@dlp ~]$
podman pod ls

POD ID        NAME        STATUS      CREATED        INFRA ID      # OF CONTAINERS
c573652d3c48  test-pod    Created     3 seconds ago  84cc75b1bd80  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

[fedora@dlp ~]$
podman run -d -p 1023:80 docker.io/library/nginx

Error: pasta failed with exit code 1:
Failed to bind port 1023 (Permission denied) for option '-t 1023-1023:80-80', exiting
[fedora@dlp ~]$
podman run -d -p 1024:80 docker.io/library/nginx

[fedora@dlp ~]$
podman ps

CONTAINER ID  IMAGE                           COMMAND               CREATED        STATUS        PORTS                 NAMES
1e178c41e89c  docker.io/library/nginx:latest  nginx -g daemon o...  5 seconds ago  Up 5 seconds  0.0.0.0:1024->80/tcp  serene_maxwell
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