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rootless: optional support for lxc-user-nic SUID binary

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lxc-user-nic can eliminate slirp overhead but needs /etc/lxc/lxc-usernet to be configured for the current user.

To use lxc-user-nic, $DOCKERD_ROOTLESS_ROOTLESSKIT_NET=lxc-user-nic also needs to be set.

This commit also bumps up RootlessKit from v0.3.0 to v0.4.0:
70e0502f32...e92d5e772e

Signed-off-by: Akihiro Suda <akihiro.suda.cz@hco.ntt.co.jp>
This commit is contained in:
Akihiro Suda 2019-04-19 17:54:29 +09:00
parent 3cd54c28fd
commit 63a66b0eb0
3 changed files with 40 additions and 21 deletions
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47
contrib/dockerd-rootless.sh
View file

@ -9,7 +9,9 @@
# External dependencies:
# * newuidmap and newgidmap needs to be installed.
# * /etc/subuid and /etc/subgid needs to be configured for the current user.
# * Either slirp4netns (v0.3+) or VPNKit needs to be installed.
# * Either one of slirp4netns (v0.3+), VPNKit, lxc-user-nic needs to be installed.
# slirp4netns is used by default if installed. Otherwise fallsback to VPNKit.
# The default value can be overridden with $DOCKERD_ROOTLESS_ROOTLESSKIT_NET=(slirp4netns|vpnkit|lxc-user-nic)
#
# See the documentation for the further information.
@ -35,24 +37,32 @@ if [ -z $rootlesskit ]; then
exit 1
fi
net=""
mtu=""
if which slirp4netns >/dev/null 2>&1; then
if slirp4netns --help | grep -- --disable-host-loopback; then
net=slirp4netns
mtu=65520
else
echo "slirp4netns does not support --disable-host-loopback. Falling back to VPNKit."
: "${DOCKERD_ROOTLESS_ROOTLESSKIT_NET:=}"
: "${DOCKERD_ROOTLESS_ROOTLESSKIT_MTU:=}"
net=$DOCKERD_ROOTLESS_ROOTLESSKIT_NET
mtu=$DOCKERD_ROOTLESS_ROOTLESSKIT_MTU
if [ -z $net ]; then
if which slirp4netns >/dev/null 2>&1; then
if slirp4netns --help | grep -- --disable-host-loopback; then
net=slirp4netns
if [ -z $mtu ]; then
mtu=65520
fi
else
echo "slirp4netns does not support --disable-host-loopback. Falling back to VPNKit."
fi
fi
if [ -z $net ]; then
if which vpnkit >/dev/null 2>&1; then
net=vpnkit
else
echo "Either slirp4netns (v0.3+) or vpnkit needs to be installed"
exit 1
fi
fi
fi
if [ -z $net ]; then
if which vpnkit >/dev/null 2>&1; then
net=vpnkit
mtu=1500
else
echo "Either slirp4netns (v0.3+) or vpnkit needs to be installed"
exit 1
fi
if [ -z $mtu ]; then
mtu=1500
fi
if [ -z $_DOCKERD_ROOTLESS_CHILD ]; then
@ -66,7 +76,8 @@ if [ -z $_DOCKERD_ROOTLESS_CHILD ]; then
# (by either systemd-networkd or NetworkManager)
# * /run: copy-up is required so that we can create /run/docker (hardcoded for plugins) in our namespace
$rootlesskit \
--net=$net --mtu=$mtu --disable-host-loopback --port-driver=builtin \
--net=$net --mtu=$mtu \
--disable-host-loopback --port-driver=builtin \
--copy-up=/etc --copy-up=/run \
$DOCKERD_ROOTLESS_ROOTLESSKIT_FLAGS \
$0 $@

10
docs/rootless.md
View file

@ -20,7 +20,6 @@ $ grep ^$(whoami): /etc/subgid
penguin:231072:65536
```
* Either [slirp4netns](https://github.com/rootless-containers/slirp4netns) (v0.3+) or [VPNKit](https://github.com/moby/vpnkit) needs to be installed. slirp4netns is preferred for the best performance.
### Distribution-specific hint
@ -82,3 +81,12 @@ To route ping packets, you need to set up `net.ipv4.ping_group_range` properly a
```console
$ sudo sh -c "echo 0 2147483647 > /proc/sys/net/ipv4/ping_group_range"
```
### Changing network stack
`dockerd-rootless.sh` uses [slirp4netns](https://github.com/rootless-containers/slirp4netns) (if installed) or [VPNKit](https://github.com/moby/vpnkit) as the network stack by default.
These network stacks run in userspace and might have performance overhead. See [RootlessKit documentation](https://github.com/rootless-containers/rootlesskit/tree/v0.4.0#network-drivers) for further information.
Optionally, you can use `lxc-user-nic` instead for the best performance.
To use `lxc-user-nic`, you need to edit [`/etc/lxc/lxc-usernet`](https://github.com/rootless-containers/rootlesskit/tree/v0.4.0#--netlxc-user-nic-experimental) and set `$DOCKERD_ROOTLESS_ROOTLESSKIT_NET=lxc-user-nic`.

4
hack/dockerfile/install/rootlesskit.installer
View file

@ -1,7 +1,7 @@
#!/bin/sh
# v0.3.0
ROOTLESSKIT_COMMIT=70e0502f328bc5ffb14692a7ea41abb77196043b
# v0.4.0
ROOTLESSKIT_COMMIT=e92d5e772ee7e103aecf380c5874a40c52876ff0
install_rootlesskit() {
case "$1" in