[Lxc-users] PostgreSQL - "sh: cannot create /dev/null: Permission denied" - LXC Issue?

Tue Jan 24 17:54:55 UTC 2012

On 24/01/2012, at 7:27 AM, Patrick Kevin McCaffrey wrote:

>
>
> ...
>
>>> I'm working on a database container, but when I run:
>>>
>>> "/usr/local/pgsql/bin/initdb -D /usr/local/pgsql/data"
>>>
>>> to set up my database, it errors out with:
>>>
>>> "sh: cannot create /dev/null: Permission denied
>>> fgets failure: Success
>>> The program "postgres" is needed by initdb but was not found in the
>>> same directory as "/usr/local/pgsql/bin/initdb".
>>> Check your installation."
>>>
>
>> Try adding this to config file:
>
>
>> lxc.cgroup.devices.allow = c 1:3 rwm
> ##This line is already in my config file.  The entire config file is  
> further below.
>
>
>> This allows the container to read/write/mknod
>> character device major 1, minor 3
>
>> tmike at tmike-Inspiron-1464:~/lxc/oneiric$ ls -l /dev/null
>> crw-rw-rw- 1 root root 1, 3 2012-01-13 13:45 /dev/null
>
>> This should take care of the
>
>> "sh: cannot create /dev/null: Permission denied
>
>
>
>
> ##  Again, sorry for the how long it took me to reply.  Getting this  
> system setup is sort of a side project, and other things have gotten  
> in the way of me working on it lately.  Anyway, When I "ls -l" on / 
> dev/nul, I get the following:
>
> crw-r--r-- 1 root root 1, 3 Jan 16 23:24 null

>What are the permissions on /dev/null before you start the container?  
>i.e. what is output of ls -l /lxc/PE1800-db0/rootfs/dev/null ?  
>Probably 644 - if so, fix the permissions for that location, then try  
>running the container again.
>
>Something else you could perhaps try - just temporarily till you find  
>the real cause of the problem - is to comment out the config line:  
>lxc.cgroup.devices.deny = a
>
>chris

Here is the output of "ls -l" before starting the containter:

pat at PowerEdge1800:/lxc$ ls -l /lxc/PE1800-db0/rootfs/dev/null
crw-r--r-- 1 root root 1, 3 Jan 16 23:24 /lxc/PE1800-db0/rootfs/dev/null

I haven't tried removing "lxc.cgroup.devices.deny = a" yet, but it seems like that's my next step.  I'm just lost as to where I've gone wrong.

-Pat

> It looks like I definitely don't have write support, if I understand  
> that output correctly.  Here is my entire config file for this  
> container:
>
> ---------------------------------------------------------------------
>
> lxc.utsname = PE1800-db0
> lxc.tty = 4
> lxc.pts = 1024
> lxc.rootfs = /lxc/PE1800-db0/rootfs
> lxc.cgroup.devices.deny = a
> lxc.network.type = veth
> lxc.network.link = br0
> #lxc.network.veth.pair =
> lxc.network.ipv4 = 192.168.80.4
> # /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
> lxc.cgroup.devices.allow = c 136:* rwm
> lxc.cgroup.devices.allow = c 5:2 rwm
> # rtc
> lxc.cgroup.devices.allow = c 254:0 rwm
>
> # mounts point
> lxc.mount.entry=proc /lxc/PE1800-db0//rootfs/proc proc  
> nodev,noexec,nosuid 0 0
> lxc.mount.entry=sysfs /lxc/PE1800-db0//rootfs/sys sysfs defaults  0 0
>
> ----------------------------------------------
>
> I still get exactly the same output when running "/usr/local/pgsql/ 
> bin/initdb -D /usr/local/pgsql/data":
>
> sh: cannot create /dev/null: Permission denied
> fgets failure: Success
> The program "postgres" is needed by initdb but was not found in the
> same directory as "/usr/local/pgsql/bin/initdb".
> Check your installation.
>
>
> Anyone?
>
>>
>> ----- Original Message -----
>> From: "Guido Jäkel" <G.Jaekel at dnb.de>
>> To: "Patrick Kevin McCaffrey" <pkm at uwm.edu>, "lxc-users"
>> <lxc-users at lists.sourceforge.net>
>> Sent: Tuesday, December 20, 2011 2:06:49 AM
>> Subject: Re: [Lxc-users] PostgreSQL - "sh: cannot create /dev/null:
>> Permission denied" - LXC Issue?
>>
>> Dear Patrick,
>>
>> As I understand /dev/null isn't writable in your container. That's
>> definitely a wrong configuration.
>>
>> Please check, that there is a real device node for  /dev/null  (and
>> others) in your container and you have it (and others) in the lxc
>> device access control list (lxc.cgroup.devices.allow = c 1:3 rw)
>>
>> Note that -- depending on the linux flavor in your LXC container --
>> you might have to populate /dev by your own, because it's not
>> reasonable to run udev or something like this inside a container.
>>
>> Greetings
>>
>> Guido
>>
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Christoph Willing              +61 7 3365 8316
Research Computing Centre
University of Queensland