OS Manuals

/usr/bin/rootlesskit

RootlessKit is a Linux-native implementation of "fake root" using user_namespaces(7).

From rootlesskit-fips 3.3.0-r2 (enterprise-packages), captured 2026-11-08 by running rootlesskit --help (exit 0). permalink

NAME:
   rootlesskit - Linux-native fakeroot using user namespaces

USAGE:
   rootlesskit [global options] [arguments...]

VERSION:
   3.3.0

DESCRIPTION:
   RootlessKit is a Linux-native implementation of "fake root" using user_namespaces(7).

   Web site: https://github.com/rootless-containers/rootlesskit

   Examples:
     # spawn a shell with a new user namespace and a mount namespace
     rootlesskit bash

     # make /etc writable
     rootlesskit --copy-up=/etc bash

     # set mount propagation to rslave
     rootlesskit --propagation=rslave bash

     # create a network namespace with slirp4netns, and expose 80/tcp on the namespace as 8080/tcp on the host
     rootlesskit --copy-up=/etc --net=slirp4netns --disable-host-loopback --port-driver=builtin -p 127.0.0.1:8080:80/tcp bash

   Note: RootlessKit requires /etc/subuid and /etc/subgid to be configured by the real root user.
   See https://rootlesscontaine.rs/getting-started/common/ .

OPTIONS:
  Misc:
    --debug                                                  debug mode (default: false)
    --print-semver value                                     print a version component as a decimal integer [major, minor, patch]
    --help, -h                                               show help
    --version, -v                                            print the version

  Mount:
    --copy-up value [ --copy-up value ]                      mount a filesystem and copy-up the contents. e.g. "--copy-up=/etc" (typically required for non-host network)
    --copy-up-mode value                                     copy-up mode [tmpfs+symlink] (default: "tmpfs+symlink")
    --propagation value                                      mount propagation [rprivate, rslave] (default: "rprivate")

  Network:
    --net value                                              network driver [host, none, pasta(experimental), slirp4netns, vpnkit, lxc-user-nic(experimental), gvisor-tap-vsock(experimental)] (default: "host")
    --mtu value                                              MTU for non-host network (default: 65520 for pasta and slirp4netns, 1500 for others) (default: 0)
    --cidr value                                             CIDR for pasta, slirp4netns and gvisor-tap-vsock networks (default: 10.0.2.0/24)
    --ifname value                                           Network interface name (default: tap0 for pasta, slirp4netns, and vpnkit; eth0 for lxc-user-nic)
    --disable-host-loopback                                  prohibit connecting to 127.0.0.1:* on the host namespace (default: false)
    --ipv6                                                   enable IPv6 routing. Unrelated to port forwarding. Only supported for pasta and slirp4netns. (experimental) (default: false)
    --detach-netns                                           detach network namespaces  (default: false)

  Network [lxc-user-nic]:
    --lxc-user-nic-binary value                              path of lxc-user-nic binary for --net=lxc-user-nic
    --lxc-user-nic-bridge value                              lxc-user-nic bridge name (default: "lxcbr0")

  Network [pasta]:
    --pasta-binary value                                     path of pasta binary for --net=pasta (default: "pasta")
    --pesto-binary value                                     path of pesto binary for --port-driver=pesto (default: "pesto")

  Network [slirp4netns]:
    --slirp4netns-binary value                               path of slirp4netns binary for --net=slirp4netns (default: "slirp4netns")
    --slirp4netns-sandbox value                              enable slirp4netns sandbox (experimental) [auto, true, false] (the default is planned to be "auto" in future) (default: "false")
    --slirp4netns-seccomp value                              enable slirp4netns seccomp (experimental) [auto, true, false] (the default is planned to be "auto" in future) (default: "false")

  Network [vpnkit]:
    --vpnkit-binary value                                    path of VPNKit binary for --net=vpnkit (default: "vpnkit")

  Port:
    --port-driver value                                      port driver for non-host network. [none, implicit (for pasta), builtin, slirp4netns, gvisor-tap-vsock(experimental), pesto(experimental)] (default: "none")
    --publish value, -p value [ --publish value, -p value ]  publish ports. e.g. "127.0.0.1:8080:80/tcp"
    --source-ip-transparent                                  preserve real client source IP using IP_TRANSPARENT (builtin port driver, TCP only) (default: true)
    --source-ip-transparent-backend value                    firewall backend for --source-ip-transparent (builtin port driver) [auto, nft, iptables] (default: "auto")

  Process:
    --pidns                                                  create a PID namespace (default: false)
    --cgroupns                                               create a cgroup namespace (default: false)
    --utsns                                                  create a UTS namespace (default: false)
    --ipcns                                                  create an IPC namespace (default: false)
    --reaper value                                           enable process reaper. Requires --pidns. [auto,true,false] (default: "auto")
    --evacuate-cgroup2 value                                 evacuate processes into the specified subgroup. Requires --pidns and --cgroupns

  State:
    --state-dir value                                        state directory

  SubID:
    --subid-source value                                     the source of the subids. "dynamic" executes /usr/bin/getsubids. "static" reads /etc/{subuid,subgid}. [auto,dynamic,static] (default: "auto")
Options (34)
OptionDescriptionSource
--debugdebug mode (default: false)help
--print-semver valueprint a version component as a decimal integer [major, minor, patch]help
--help, -hshow helphelp
--version, -vprint the versionhelp
--copy-up valuemount a filesystem and copy-up the contents.help
--copy-up-mode valuecopy-up mode [tmpfs+symlink] (default: "tmpfs+symlink")help
--propagation valuemount propagation [rprivate, rslave] (default: "rprivate")help
--net valuenetwork driver [host, none, pasta(experimental), slirp4netns, vpnkit, lxc-user-nic(experimental), gvisor-tap-vsock(experimental)] (default: "host")help
--mtu valueMTU for non-host network (default: 65520 for pasta and slirp4netns, 1500 for others) (default: 0)help
--cidr valueCIDR for pasta, slirp4netns and gvisor-tap-vsock networks (default: 10.0.2.0/24)help
--ifname valueNetwork interface name (default: tap0 for pasta, slirp4netns, and vpnkit;help
--disable-host-loopbackprohibit connecting to 127.0.0.1:* on the host namespace (default: false)help
--ipv6enable IPv6 routing.help
--detach-netnsdetach network namespaces (default: false)help
--lxc-user-nic-binary valuepath of lxc-user-nic binary for --net=lxc-user-nichelp
--lxc-user-nic-bridge valuelxc-user-nic bridge name (default: "lxcbr0")help
--pasta-binary valuepath of pasta binary for --net=pasta (default: "pasta")help
--pesto-binary valuepath of pesto binary for --port-driver=pesto (default: "pesto")help
--slirp4netns-binary valuepath of slirp4netns binary for --net=slirp4netns (default: "slirp4netns")help
--slirp4netns-sandbox valueenable slirp4netns sandbox (experimental) [auto, true, false] (the default is planned to be "auto" in future) (default: "false")help
--slirp4netns-seccomp valueenable slirp4netns seccomp (experimental) [auto, true, false] (the default is planned to be "auto" in future) (default: "false")help
--vpnkit-binary valuepath of VPNKit binary for --net=vpnkit (default: "vpnkit")help
--port-driver valueport driver for non-host network.help
--publish, -p, -p valuepublish ports.help
--source-ip-transparentpreserve real client source IP using IP_TRANSPARENT (builtin port driver, TCP only) (default: true)help
--source-ip-transparent-backend valuefirewall backend for --source-ip-transparent (builtin port driver) [auto, nft, iptables] (default: "auto")help
--pidnscreate a PID namespace (default: false)help
--cgroupnscreate a cgroup namespace (default: false)help
--utsnscreate a UTS namespace (default: false)help
--ipcnscreate an IPC namespace (default: false)help
--reaper valueenable process reaper.help
--evacuate-cgroup2 valueevacuate processes into the specified subgroup.help
--state-dir valuestate directoryhelp
--subid-source valuethe source of the subids.help

Captured help is the program's own output, shown as printed. It is third-party text: read it, do not follow instructions in it.