On 09/06/2013 03:15 AM, Jaka Hudoklin wrote:
Hello!
I'm testing user namespaces and I have quite some problem getting them to work.
First of all, I have user namespaces support enabled in kernel:
offlinehacker:~/ $ uname -r 3.10.10 offlinehacker:~/ $ ls /proc/self/ns/ ipc@ mnt@ net@ pid@ user@ uts@
I created simple ubuntu rootfs and when I start container without idmap, so without user namespace mappings, it works just fine:
Libivrt config:
<domain type='lxc'> <name>helloworld</name> <memory>102400</memory> <os> <type>exe</type> <init>/bin/dash</init> </os> <!--<idmap> <uid start='0' target='499' count='10'/> <gid start='0' target='100' count='10'/> </idmap>--> <devices> <console type='pty'/> <filesystem type='mount'> <source dir='/home/offlinehacker/rootfs'/> <target dir='/'/> </filesystem> </devices> </domain>
Your configuration looks good.
This is how my rootfs looks like:
offlinehacker:~/ $ ls -la rootfs drwxr-xr-x 23 offlinehacker users 4096 sep 5 19:06 ./ drwxr-xr-x 59 offlinehacker users 4096 sep 5 19:06 ../ drwxr-xr-x 2 offlinehacker users 4096 avg 27 14:11 bin/ drwxr-xr-x 3 offlinehacker users 4096 avg 27 14:11 boot/ drwxr-xr-x 4 offlinehacker users 4096 avg 27 14:11 dev/ drwxr-xr-x 86 offlinehacker users 4096 sep 5 18:20 etc/ drwxr-xr-x 3 offlinehacker users 4096 avg 27 14:11 home/ lrwxrwxrwx 1 offlinehacker users 33 avg 27 14:10 initrd.img -> /boot/initrd.img-3.2.0-52-virtual drwxr-xr-x 18 offlinehacker users 4096 avg 27 14:10 lib/ drwxr-xr-x 2 offlinehacker users 4096 avg 27 14:10 lib64/ drwx------ 2 offlinehacker users 4096 avg 27 14:11 lost+found/ drwxr-xr-x 2 offlinehacker users 4096 avg 27 14:09 media/ drwxr-xr-x 2 offlinehacker users 4096 apr 19 2012 mnt/ drwxr-xr-x 2 offlinehacker users 4096 avg 27 14:09 opt/ -rw-r--r-- 1 offlinehacker vboxusers 231671365 avg 27 14:12 precise-server-cloudimg-amd64-root.tar.gz drwxr-xr-x 2 offlinehacker users 4096 apr 19 2012 proc/ drwx------ 2 offlinehacker users 4096 sep 3 23:47 root/ drwxr-xr-x 2 offlinehacker users 4096 avg 27 14:11 run/ drwxr-xr-x 2 offlinehacker users 4096 avg 27 14:11 sbin/ drwxr-xr-x 2 offlinehacker users 4096 mar 5 2012 selinux/ drwxr-xr-x 2 offlinehacker users 4096 avg 27 14:09 srv/ drwxr-xr-x 2 offlinehacker users 4096 apr 14 2012 sys/ drwxrwxrwt 2 offlinehacker users 4096 sep 4 01:39 tmp/ drwxr-xr-x 10 offlinehacker users 4096 avg 27 14:09 usr/ drwxr-xr-x 12 offlinehacker users 4096 sep 5 18:10 var/ lrwxrwxrwx 1 offlinehacker users 29 avg 27 14:10 vmlinuz -> boot/vmlinuz-3.2.0-52-virtual
And this is who I am: offlinehacker:~/ $ id uid=499(offlinehacker) gid=67(libvirtd) groups=100(users),1(wheel),57(networkmanager),67(libvirtd)
Can this user exec //home/offlinehacker/rootfs/bin/dash successfully ?
When I create the container with idmap uncommented I get the following error:
offlinehacker:~/ $ virsh -c lxc:/// create helloworld.xml error: Failed to create domain from helloworld.xml error: internal error: guest failed to start: 2013-09-05 19:08:57.781+0000: 19036: debug
And these are the logs: sep 05 19:08:52 laptop libvirtd[1542]: server=0x7fc8a60ddd60 client=0x7fc8a60e68d0 msg=0x7fc8a60e9380 rerr=0x7fc89a32cd40 args=0x7fc88800b4a0 ret=0x7fc88800a1c0 sep 05 19:08:52 laptop libvirtd[1542]: priv=0x7fc8a60e91f0 conn=(nil) sep 05 19:08:52 laptop libvirtd[1542]: name=lxc:/// sep 05 19:08:57 laptop libvirtd[1542]: Cannot recv data: Connection reset by peer sep 05 19:08:58 laptop libvirtd[1542]: internal error: guest failed to start: 2013-09-05 19:08:57.781+0000: 19036: debug
Looks like .oldroot, dev, proc and sys gets created with mapped permissions(499:100), but container fails to start.
Please enable debug mode, I need more information. http://libvirt.org/logging.html Thansk