[Devel] Re: liblxc: lxc-debian

[Daniel Lezcano]

Serge E. Hallyn wrote:
> Quoting Daniel Lezcano (dlezcano at fr.ibm.com):
>> Serge E. Hallyn wrote:
>>> Quoting Matt Helsley (matthltc at us.ibm.com):
>>>>         #
>>>>         # Write some reasonable default device whitelist rules
>>>>         #
>>>>         cat - >> $CONFFILE <<-"EOF"
>>>>         lxc.cgroup.devices.deny = a
>>>>         # /dev/null and zero
>>>>         lxc.cgroup.devices.allow = c 1:3 rwm
>>>>         lxc.cgroup.devices.allow = c 1:5 rwm
>>>>         # consoles
>>>>         lxc.cgroup.devices.allow = c 5:1 rwm
>>>>         lxc.cgroup.devices.allow = c 5:0 rwm
>>>>         lxc.cgroup.devices.allow = c 4:0 rwm
>>>>         lxc.cgroup.devices.allow = c 4:1 rwm
>>>>         # /dev/{,u}random
>>>>         lxc.cgroup.devices.allow = c 1:9 rwm
>>>>         lxc.cgroup.devices.allow = c 1:8 rwm
>>>>         # /dev/pts/* - pts namespaces are "coming soon"
>>>>         lxc.cgroup.devices.allow = c 136:* rwm
>>>>         # rtc         lxc.cgroup.devices.allow = c 254:0 rwm
>>>>         EOF
>>>>
>>>> The quotes around EOF prevent bash from doing any substitution on the
>>>> file contents.
>> I added these devices to the debian configuration file and fixed the  
>> cgroup list order, "lxc.cgroup.devices.deny = a" was the last entry :/
> 
> Weird.  It's the first now I hope :)

I meant it was a bug of liblxc to store the cgroup in the wrong order :)

>> By default the debian has no root password, so the ssh connection will  
>> always fail until a password is set for root. I will look on how to  
>> change the root password to 'root' after debootstraping ...
>>
>> I added "lxc.cgroup.devices.allow = c 5:2 rwm"
>> in order to use /dev/ptmx for the tty's ssh connection.
>>
>> The container is no longer able to create /dev/initctl, so the poweroff  
>> command will fail. Serge do you know what is the syntax for the  
>> devices.allow for initctl ?
> 
> initctl isn't a device, it's a fifo.  At least on my laptop.

Yes, right.
"devices.deny = a" prohibits the creation of this fifo in /dev.

After doing "lxc-cgroup -n debian devices.allow a",
mknod -m 600 /dev/initctl p ,
succeed in the debian container.

(rm /dev/initctl)

But after doing "lxc-cgroup -n debian devices.deny a",
mknod -m 600 /dev/initctl p
mknod: `/dev/initctl': Operation not permitted

Is is a way to specify this fifo for devices.allow ?


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