Docker : Use by common users2021/04/06 |
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It's possible to use Docker containers by common users.
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| [1] | By default, sub UID/GID that are used on user name spaces are assigned to run containers. |
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# install Rootless package (generally it's already installed for dependency) [root@dlp ~]# dnf --enablerepo=docker-ce-stable -y install docker-ce-rootless-extras # sub UID/GID mapping file # 100000 to 165535 (100000 + 65536 - 1) UID are used for running processes in containers on [cent] user [root@dlp ~]# cat /etc/subuid cent:100000:65536 [root@dlp ~]# cat /etc/subgid cent: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 centos [root@dlp ~]# useradd redhat [root@dlp ~]# cat /etc/subgid /etc/subgid cent:100000:65536 centos:165536:65536 redhat:231072:65536 cent:100000:65536 centos:165536:65536 redhat:231072:65536 |
| [2] | It's possible to run [docker] by common users. |
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# setup rootless mode by each user itself [cent@dlp ~]$ dockerd-rootless-setuptool.sh install [INFO] Creating /home/cent/.config/systemd/user/docker.service [INFO] starting systemd service docker.service + systemctl --user start docker.service ..... ..... [INFO] To run docker.service on system startup, run: `sudo loginctl enable-linger cent` [INFO] Make sure the following environment variables are set (or add them to ~/.bashrc): export PATH=/usr/bin:$PATH export DOCKER_HOST=unix:///run/user/1000/docker.sock # load displayed environment variables [cent@dlp ~]$ export PATH=/usr/bin:$PATH [cent@dlp ~]$ export DOCKER_HOST=unix:///run/user/1000/docker.sock
docker pull centos [cent@dlp ~]$ docker images REPOSITORY TAG IMAGE ID CREATED SIZE centos latest 300e315adb2f 3 months ago 209MB
[cent@dlp ~]$
docker run centos echo "run rootless containers" run rootless containers # containers related files are located under the [$HOME/.local] directory [cent@dlp ~]$ ll ~/.local/share/docker total 0 drwx--x--x. 4 cent cent 120 Apr 6 01:38 buildkit drwx--x--x. 3 cent cent 20 Apr 6 01:38 containerd drwx-----x. 3 cent cent 78 Apr 6 01:45 containers drwx-----x. 6 cent cent 236 Apr 6 01:45 fuse-overlayfs drwx------. 3 cent cent 28 Apr 6 01:38 image drwxr-x---. 3 cent cent 19 Apr 6 01:38 network drwx------. 4 cent cent 32 Apr 6 01:38 plugins drwx------. 2 cent cent 6 Apr 6 01:38 runtimes drwx------. 2 cent cent 6 Apr 6 01:38 swarm drwx------. 2 cent cent 6 Apr 6 01:42 tmp drwx------. 2 cent cent 6 Apr 6 01:38 trust drwx-----x. 2 cent cent 25 Apr 6 01:38 volumes # for port mapping, # it's impossible to use less than [1024] ports on Host machine by common users # possible to use over [1024] ports [cent@dlp ~]$ docker run -t -d -p 1023:80 srv.world/centos-nginx /usr/sbin/nginx -g "daemon off;" docker: Error response from daemon: driver failed programming external connectivity on endpoint thirsty_haibt (31bd9b8058f11434e0ffc33209359f35574699caf5bc27a7e9e1b90f53095351): Error starting userland proxy: error while calling PortManager.AddPort(): cannot expose privileged port 1023, you can add 'net.ipv4.ip_unprivileged_port_start=1023' to /etc/sysctl.conf (currently 1024), or set CAP_NET_BIND_SERVICE on rootlesskit binary, or choose a larger port number (>= 1024): listen tcp 0.0.0.0:1023: bind: permission denied.[cent@dlp ~]$ docker run -t -d -p 1024:80 srv.world/centos-nginx /usr/sbin/nginx -g "daemon off;" [cent@dlp ~]$ docker ps CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES 015c90358f47 srv.world/centos-nginx "/usr/sbin/nginx -g …" 5 seconds ago Up 4 seconds 0.0.0.0:1024->80/tcp ecstatic_margulis |
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