lxc-unshare — Run a task in a new set of namespaces.
Synopsis
lxc-unshare {-s, --namespaces namespaces} [-u, --user user] [-H, --hostname hostname] [-i, --ifname ifname] [-d, --daemon] [-M, --remount] {command}
Description
lxc-unshare can be used to run a task in a cloned set of namespaces. This command is mainly provided for testing purposes. Despite its name, it always uses clone rather than unshare to create the new task with fresh namespaces. Apart from testing kernel regressions this should make no difference.
Options
- -s, --namespaces namespaces
Specify the namespaces to attach to, as a pipe-separated list, e.g. NETWORK|IPC. Allowed values are MOUNT, PID, UTSNAME, IPC, USER and NETWORK. This allows one to change the context of the process to e.g. the network namespace of the container while retaining the other namespaces as those of the host. (The pipe symbol needs to be escaped, e.g. MOUNT\|PID or quoted, e.g. "MOUNT|PID".)
- -u, --user user
Specify a userid which the new task should become.
- -H, --hostname hostname
Set the hostname in the new container. Only allowed if the UTSNAME namespace is set.
- -i, --ifname interfacename
Move the named interface into the container. Only allowed if the NETWORK namespace is set. You may specify this argument multiple times to move multiple interfaces into container.
- -d, --daemon
Daemonize (do not wait for the container to exit before exiting)
- -M, --remount
Mount default filesystems (/proc /dev/shm and /dev/mqueue) in the container. Only allowed if MOUNT namespace is set.
Examples
To spawn a new shell with its own UTS (hostname) namespace,
lxc-unshare -s UTSNAME /bin/bashIf the hostname is changed in that shell, the change will not be reflected on the host.
To spawn a shell in a new network, pid, and mount namespace,
lxc-unshare -s "NETWORK|PID|MOUNT" /bin/bashThe resulting shell will have pid 1 and will see no network interfaces. After re-mounting /proc in that shell,
mount -t proc proc /procps output will show there are no other processes in the namespace.
To spawn a shell in a new network, pid, mount, and hostname namespace.
lxc-unshare -s "NETWORK|PID|MOUNT|UTSNAME" -M -H myhostname -i veth1 /bin/bashThe resulting shell will have pid 1 and will see two network interfaces (lo and veth1). The hostname will be "myhostname" and /proc will have been remounted. ps output will show there are no other processes in the namespace.
See Also
lxc(7), lxc-create(1), lxc-copy(1), lxc-destroy(1), lxc-start(1), lxc-stop(1), lxc-execute(1), lxc-console(1), lxc-monitor(1), lxc-wait(1), lxc-cgroup(1), lxc-ls(1), lxc-info(1), lxc-freeze(1), lxc-unfreeze(1), lxc-attach(1), lxc.conf(5)