*paid install help?*: Cobbler on a OpenVZ container / "dhcpd" failing

Bob Cochran bcochran13 at verizon.net
Sat Jul 23 00:09:08 UTC 2011


At the request of Mr. Hoffman, I am forwarding his solution to this
problem. He is having difficulty sending email to the list at this time.
I have set up an OpenVZ container on one of my machines, and have
bridged networking set up and running, but have not yet had time to
implement dhcpd.


Here are is Frank's solution:
---------------------------------------------------------------------------

Dear All:

Last week I had asked for your advice for installing Cobbler onto a 
OpenVZ container (VPS). First of all, thanks a lot really to Marek 
Dohojda and Bob Cochran for the great comments and the assistance.

I did open a paid support ticket with 'Parallels' (Makers of 
Virtuozzo, etc.), and the support was coming forward VERY slow. But 
they did finally get me the how-to and helped fixing the DHCP 
problem. Here the summary:

In addition to the HOW-TO page posted here by Marek or Bob ...
http://wiki.openvz.org/Common_Networking_HOWTOs
... they also pointed to these pages:
http://wiki.openvz.org/VEs_and_HNs_in_same_subnets
and
http://wiki.openvz.org/Virtual_Ethernet_device  (!!!)

The 2nd link is an actual HOW-TO for setting up a network and DHCP on 
a VPS. if you start there while creating a new VPS this probably 
works. In my case I had already a VPS created (with an assigned IP 
and Cobbler installed), so some settings as regards to the bridging 
part needed to be corrected. Below the details, maybe that can be 
helpful for others.

(1) The hardware server has the configured bridge interface 'vzbr0' 
connected to the physical (node's) interface 'eth0'.
(2) To have the container connected to this network (as being plugged 
into the same switch), the container should have an Ethernet 
interface which is linked with this bridge interface on the node. 
This is done for the container #101 in the following way (remove 
existing, and add it back with the proper values):

[root at node ~]# vzctl set 101 --save --netif_del eth0
Deleting veth devices: veth101.0
Saved parameters for CT 101
[root at node ~]# vzctl set 101 --save --netif_add 
eth0,00:13:41:8A:A5:19,veth101.0,00:12:31:2C:B0:F3,vzbr0
Configure veth devices: veth101.0
Saved parameters for CT 101

(3) The difference in the configuration file for this container 
(/etc/sysconfig/vz-scripts/101.conf) is in the following line (was 
fixed by Parallels):
BEFORE: 
NETIF="ifname=eth0,mac=00:13:41:8A:A5:19,host_ifname=veth112.0,host_mac=00:12:31:2C:B0:F3"
AFTER: 
NETIF="ifname=eth0,bridge=vzbr0,mac=00:13:41:8A:A5:19,host_ifname=veth112.0,host_mac=00:00:12:31:2C:B0:F3"

(4) To utilize the bridge parameter, the file "/etc/vz/vznet.conf" 
should be created on the node, as said. With this, the container is 
connected automatically to the network and accessible:

[root at all ~]# echo -e 
'#!/bin/bash\nEXTERNAL_SCRIPT="/usr/sbin/vznetaddbr"' > 
/etc/vz/vznet.conf
[root at all ~]# vzctl restart 101
Restarting container
Stopping container ...
Container was stopped
Container is unmounted
Starting container ...
Container is mounted
Setting CPU limit: 450
Setting CPU units: 1000
Setting CPUs: 8
Set hostname: cobbler.xxxxx.com
File resolv.conf was modified
Setting quota ugidlimit: 10000
Configure veth devices: veth101.0
Adding interface veth101.0 to bridge vzbr0 on CT0 for CT101
Container start in progress...

(5) The configuration files "ifcfg-br0" and "ifcfg-veth101.0" in the 
container are not necessary and can be moved from 
"/etc/sysconfig/network-scripts/" to "/root/" or deleted.



Best,
Frank
---------------------------------------

Respectfully forwarded by 

Bob Cochran 



On 7/12/11 7:29 PM, Frank wrote:
> Okay, the how-to instructions are pretty clear on both URLs posted. 
> But this is still a little above my head as I am not fully 
> understanding what's happening.
>
> http://forum.openvz.org/index.php?t=msg&goto=33837
>
> The how-to here, that is on the VPS/container -- or on the the host 
> note? (I beg for your patience.) I tried that on the VPS, and this 
> does not work for me.
>
>
> Frank
>
> _______________________________________________
> cobbler mailing list
> cobbler at lists.fedorahosted.org
> https://fedorahosted.org/mailman/listinfo/cobbler
>


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