--net=host error: unable to remount sys readonly

[leth]

Using the default execution driver I get the following error on Linux Mint 17:

$ docker run -ti --net=host ubuntu:14.04 /bin/bash --login
2014/07/07 16:43:02 unable to remount sys readonly: unable to mount sys as readonly max retries reached

Changing to the lxc backend fixes it.

$ docker --version
Docker version 1.0.1, build 990021a

[gpabdo]

Mind posting how you switched to the lxc backend?
Thanks

[leth]

Use the -e lxc parameter to the docker daemon.
NB: you must have lxc installed.

Run echo 'DOCKER_OPTS="$DOCKER_OPTS -e lxc"' | sudo tee -a /etc/default/docker > /dev/null then restart the docker daemon.

[gpabdo]

Thanks! That worked, big help.

[soichih]

I am having the same problem on Ubuntu 14.04 / docker 1.1.0.

I've added the DOCKER_OPTS="-e lxc" on my /etc/default/docker, but after that docker seems to be dying right after it's started.

root@ubuntu13-work:/var/log# service docker restartstop: Unknown instance:
docker start/running, process 7362
root@ubuntu13-work:/var/log# service docker status
docker stop/waiting
root@ubuntu13-work:/var/log# ps -ef | grep docker
root 7871 5001 0 12:14 pts/10 00:00:00 grep --color=auto docker

[leth]

Check you have lxc installed, and try rebooting

Sent from my phone. Please excuse my brevity.

[soichih]

I've installed lxc and it started working. Thanks!

I've followed the installation guide posted here > https://docs.docker.com/installation/ubuntulinux/#ubuntu-trusty-1404-lts-64-bit

It looks like this doc should be updated.

[leth]

lxc isn't needed unless you choose to run the lxc backend.
IMO you should be able to use --net=host with the default backend (libcontainer iirc); so you don't need lxc.

[unclejack]

This has been fixed by a libcontainer update and the fix is on master. The fix for this issue will be included in the upcoming release.

[leth]

Awesome, thanks!

[leth]

@unclejack Is this fix released yet? I'm still seeing this issue on Docker version 1.1.2, build d84a070

[unclejack]

@leth No, it hasn't been released yet, but there's an upcoming release which will contain this fix (including many other fixes and improvements).