nsenter
runs a program with namespaces of another process
TLDR
Run command in all namespaces of a process
$ nsenter -t 1234 -a command
Enter mount namespace of a process$ nsenter -t 1234 --mount command
Enter network namespace of a process$ nsenter -t 1234 --net command
Enter PID namespace of a process$ nsenter -t 1234 --pid command
Enter multiple namespaces (UTS, time, IPC)$ nsenter -t 1234 -u -T -i -- command
Enter namespace via procfs reference$ nsenter --net=/proc/1234/ns/net command
SYNOPSIS
nsenter [options] [program [arguments]]
DESCRIPTION
nsenter runs a program with namespaces of another process. It is particularly useful for entering Docker containers, debugging processes in different namespaces, or working with chroot jails. If no program is specified, it runs the default shell.
PARAMETERS
-t, --target pid
Specify source process for namespace contexts-a, --all
Enter all namespaces of the target process-m, --mount[=file]
Enter mount namespace-u, --uts[=file]
Enter UTS (hostname/domainname) namespace-i, --ipc[=file]
Enter IPC namespace-n, --net[=file]
Enter network namespace-p, --pid[=file]
Enter PID namespace-U, --user[=file]
Enter user namespace-C, --cgroup[=file]
Enter cgroup namespace-T, --time[=file]
Enter time namespace-S, --setuid uid
Set user ID in entered namespace-G, --setgid gid
Set group ID in entered namespace-F, --no-fork
Do not fork before executing the program-w, --wd[=directory]
Set working directory-r, --root[=directory]
Set root directory
INSTALL
sudo apt install util-linux
sudo dnf install util-linux
sudo pacman -S util-linux
sudo apk add util-linux-misc
sudo zypper install util-linux
brew install util-linux
nix profile install nixpkgs#util-linux
CAVEATS
Entering a PID namespace causes nsenter to fork by default. Use --no-fork to disable this behavior. Appropriate privileges are required to enter namespaces owned by other users.
HISTORY
nsenter is part of the util-linux package. It uses the setns(2) system call introduced in Linux 3.0 to enter existing namespaces.
SEE ALSO
unshare(1), clone(2), namespaces(7)