contrib/dockerd-rootless.sh
#!/bin/sh
# dockerd-rootless.sh executes dockerd in rootless mode.
#
# Usage: dockerd-rootless.sh [DOCKERD_OPTIONS]
#
# External dependencies:
# * newuidmap and newgidmap needs to be installed.
# * /etc/subuid and /etc/subgid needs to be configured for the current user.
# * Either one of slirp4netns (>= v0.4.0), VPNKit, lxc-user-nic needs to be installed.
#
# Recognized environment variables:
# * DOCKERD_ROOTLESS_ROOTLESSKIT_STATE_DIR=DIR: the rootlesskit state dir. Defaults to "$XDG_RUNTIME_DIR/dockerd-rootless".
# * DOCKERD_ROOTLESS_ROOTLESSKIT_NET=(slirp4netns|vpnkit|pasta|lxc-user-nic): the rootlesskit network driver. Defaults to "slirp4netns" if slirp4netns (>= v0.4.0) is installed. Otherwise defaults to "vpnkit".
# * DOCKERD_ROOTLESS_ROOTLESSKIT_MTU=NUM: the MTU value for the rootlesskit network driver. Defaults to 65520 for slirp4netns, 1500 for other drivers.
# * DOCKERD_ROOTLESS_ROOTLESSKIT_PORT_DRIVER=(builtin|slirp4netns|implicit): the rootlesskit port driver. Defaults to "builtin".
# * DOCKERD_ROOTLESS_ROOTLESSKIT_SLIRP4NETNS_SANDBOX=(auto|true|false): whether to protect slirp4netns with a dedicated mount namespace. Defaults to "auto".
# * DOCKERD_ROOTLESS_ROOTLESSKIT_SLIRP4NETNS_SECCOMP=(auto|true|false): whether to protect slirp4netns with seccomp. Defaults to "auto".
# * DOCKERD_ROOTLESS_ROOTLESSKIT_DISABLE_HOST_LOOPBACK=(true|false): prohibit connections to 127.0.0.1 on the host (including via 10.0.2.2, in the case of slirp4netns). Defaults to "true".
# To apply an environment variable via systemd, create ~/.config/systemd/user/docker.service.d/override.conf as follows,
# and run `systemctl --user daemon-reload && systemctl --user restart docker`:
# --- BEGIN ---
# [Service]
# Environment="DOCKERD_ROOTLESS_ROOTLESSKIT_NET=pasta"
# Environment="DOCKERD_ROOTLESS_ROOTLESSKIT_PORT_DRIVER=implicit"
# --- END ---
# Guide to choose the network driver and the port driver:
#
# Network driver | Port driver | Net throughput | Port throughput | Src IP | No SUID | Note
# ---------------|----------------|----------------|-----------------|--------|---------|---------------------------------------------------------
# slirp4netns | builtin | Slow | Fast ✅ | ❌ | ✅ | Default in typical setup
# vpnkit | builtin | Slow | Fast ✅ | ❌ | ✅ | Default when slirp4netns is not installed
# slirp4netns | slirp4netns | Slow | Slow | ✅ | ✅ |
# pasta | implicit | Slow | Fast ✅ | ✅ | ✅ | Experimental; Needs recent version of pasta (2023_12_04)
# lxc-user-nic | builtin | Fast ✅ | Fast ✅ | ❌ | ❌ | Experimental
# (bypass4netns) | (bypass4netns) | Fast ✅ | Fast ✅ | ✅ | ✅ | (Not integrated to RootlessKit)
# See the documentation for the further information: https://docs.docker.com/go/rootless/
set -e -x
case "$1" in
"check" | "install" | "uninstall")
echo "Did you mean 'dockerd-rootless-setuptool.sh $@' ?"
exit 1
;;
esac
if ! [ -w "$XDG_RUNTIME_DIR" ]; then
echo "XDG_RUNTIME_DIR needs to be set and writable"
exit 1
fi
if ! [ -d "$HOME" ]; then
echo "HOME needs to be set and exist."
exit 1
fi
rootlesskit=""
for f in docker-rootlesskit rootlesskit; do
if command -v $f > /dev/null 2>&1; then
rootlesskit=$f
break
fi
done
if [ -z "$rootlesskit" ]; then
echo "rootlesskit needs to be installed"
exit 1
fi
: "${DOCKERD_ROOTLESS_ROOTLESSKIT_STATE_DIR:=$XDG_RUNTIME_DIR/dockerd-rootless}"
: "${DOCKERD_ROOTLESS_ROOTLESSKIT_NET:=}"
: "${DOCKERD_ROOTLESS_ROOTLESSKIT_MTU:=}"
: "${DOCKERD_ROOTLESS_ROOTLESSKIT_PORT_DRIVER:=builtin}"
: "${DOCKERD_ROOTLESS_ROOTLESSKIT_SLIRP4NETNS_SANDBOX:=auto}"
: "${DOCKERD_ROOTLESS_ROOTLESSKIT_SLIRP4NETNS_SECCOMP:=auto}"
: "${DOCKERD_ROOTLESS_ROOTLESSKIT_DISABLE_HOST_LOOPBACK:=}"
net=$DOCKERD_ROOTLESS_ROOTLESSKIT_NET
mtu=$DOCKERD_ROOTLESS_ROOTLESSKIT_MTU
if [ -z "$net" ]; then
if command -v slirp4netns > /dev/null 2>&1; then
# If --netns-type is present in --help, slirp4netns is >= v0.4.0.
if slirp4netns --help | grep -qw -- --netns-type; then
net=slirp4netns
if [ -z "$mtu" ]; then
mtu=65520
fi
else
echo "slirp4netns found but seems older than v0.4.0. Falling back to VPNKit."
fi
fi
if [ -z "$net" ]; then
if command -v vpnkit > /dev/null 2>&1; then
net=vpnkit
else
echo "Either slirp4netns (>= v0.4.0) or vpnkit needs to be installed"
exit 1
fi
fi
fi
if [ -z "$mtu" ]; then
mtu=1500
fi
host_loopback="--disable-host-loopback"
if [ "$DOCKERD_ROOTLESS_ROOTLESSKIT_DISABLE_HOST_LOOPBACK" = "false" ]; then
host_loopback=""
fi
dockerd="${DOCKERD:-dockerd}"
if [ -z "$_DOCKERD_ROOTLESS_CHILD" ]; then
_DOCKERD_ROOTLESS_CHILD=1
export _DOCKERD_ROOTLESS_CHILD
if [ "$(id -u)" = "0" ]; then
echo "This script must be executed as a non-privileged user"
exit 1
fi
# `selinuxenabled` always returns false in RootlessKit child, so we execute `selinuxenabled` in the parent.
# https://github.com/rootless-containers/rootlesskit/issues/94
if command -v selinuxenabled > /dev/null 2>&1 && selinuxenabled; then
_DOCKERD_ROOTLESS_SELINUX=1
export _DOCKERD_ROOTLESS_SELINUX
fi
# Re-exec the script via RootlessKit, so as to create unprivileged {user,mount,network} namespaces.
#
# --copy-up allows removing/creating files in the directories by creating tmpfs and symlinks
# * /etc: copy-up is required so as to prevent `/etc/resolv.conf` in the
# namespace from being unexpectedly unmounted when `/etc/resolv.conf` is recreated on the host
# (by either systemd-networkd or NetworkManager)
# * /run: copy-up is required so that we can create /run/docker (hardcoded for plugins) in our namespace
exec $rootlesskit \
--state-dir=$DOCKERD_ROOTLESS_ROOTLESSKIT_STATE_DIR \
--net=$net --mtu=$mtu \
--slirp4netns-sandbox=$DOCKERD_ROOTLESS_ROOTLESSKIT_SLIRP4NETNS_SANDBOX \
--slirp4netns-seccomp=$DOCKERD_ROOTLESS_ROOTLESSKIT_SLIRP4NETNS_SECCOMP \
$host_loopback --port-driver=$DOCKERD_ROOTLESS_ROOTLESSKIT_PORT_DRIVER \
--copy-up=/etc --copy-up=/run \
--propagation=rslave \
$DOCKERD_ROOTLESS_ROOTLESSKIT_FLAGS \
"$0" "$@"
else
[ "$_DOCKERD_ROOTLESS_CHILD" = 1 ]
# remove the symlinks for the existing files in the parent namespace if any,
# so that we can create our own files in our mount namespace.
rm -f /run/docker /run/containerd /run/xtables.lock
if [ -n "$_DOCKERD_ROOTLESS_SELINUX" ]; then
# iptables requires /run in the child to be relabeled. The actual /run in the parent is unaffected.
# https://github.com/containers/podman/blob/e6fc34b71aa9d876b1218efe90e14f8b912b0603/libpod/networking_linux.go#L396-L401
# https://github.com/moby/moby/issues/41230
chcon system_u:object_r:iptables_var_run_t:s0 /run
fi
if [ "$(stat -c %T -f /etc)" = "tmpfs" ] && [ -L "/etc/ssl" ]; then
# Workaround for "x509: certificate signed by unknown authority" on openSUSE Tumbleweed.
# https://github.com/rootless-containers/rootlesskit/issues/225
realpath_etc_ssl=$(realpath /etc/ssl)
rm -f /etc/ssl
mkdir /etc/ssl
mount --rbind ${realpath_etc_ssl} /etc/ssl
fi
exec "$dockerd" "$@"
fi