Installing And Using OpenVZ On Debian Squeeze (AMD64) - Page 2

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3 Using OpenVZ

Before we can create virtual machines with OpenVZ, we need to have a template for the distribution that we want to use in the virtual machines in the /var/lib/vz/template/cache directory. The virtual machines will be created from that template.

You can find a list of precreated templates on For example, we can download a minimal Debian Squeeze template (x86_64) as follows:

cd /var/lib/vz/template/cache

(If your host is an i386 system, you cannot use an amd64 template - you must use i386 templates then!)

I will now show you the basic commands for using OpenVZ.

To set up a VPS from the debian-6.0-amd64-minimal template (you can find it in /var/lib/vz/template/cache), run:

vzctl create 101 --ostemplate debian-6.0-amd64-minimal --config basic

The 101 must be a uniqe ID - each virtual machine must have its own unique ID. You can use the last part of the virtual machine's IP address for it. For example, if the virtual machine's IP address is, you use 101 as the ID.

If you want to have the vm started at boot, run

vzctl set 101 --onboot yes --save

To set a hostname and IP address for the vm, run:

vzctl set 101 --hostname --save
vzctl set 101 --ipadd --save

Next we set the number of sockets to 120 and assign a few nameservers to the vm:

vzctl set 101 --numothersock 120 --save
vzctl set 101 --nameserver --nameserver --save

(Instead of using the vzctl set commands, you can as well directly edit the vm's configuration file which is stored in the /etc/vz/conf directory. If the ID of the vm is 101, then the configuration file is /etc/vz/conf/101.conf.)

To start the vm, run

vzctl start 101 

To set a root password for the vm, execute

vzctl exec 101 passwd

You can now either connect to the vm via SSH (e.g. with PuTTY), or you enter it as follows:

vzctl enter 101 

To leave the vm's console, type


To stop a vm, run

vzctl stop 101

To restart a vm, run

vzctl restart 101

To delete a vm from the hard drive (it must be stopped before you can do this), run

vzctl destroy 101 

To get a list of your vms and their statuses, run

vzlist -a

[email protected]:~# vzlist -a
       101          8 running
[email protected]:~#

To find out about the resources allocated to a vm, run

vzctl exec 101 cat /proc/user_beancounters

server1:~# vzctl exec 101 cat /proc/user_beancounters
Version: 2.5
       uid  resource           held    maxheld    barrier      limit    failcnt
      101:  kmemsize         500737     517142   11055923   11377049          0
            lockedpages           0          0        256        256          0
            privvmpages        2315       2337      65536      69632          0
            shmpages            640        640      21504      21504          0
            dummy                 0          0          0          0          0
            numproc               7          7        240        240          0
            physpages          1258       1289          0 2147483647          0
            vmguarpages           0          0      33792 2147483647          0
            oomguarpages       1258       1289      26112 2147483647          0
            numtcpsock            2          2        360        360          0
            numflock              1          1        188        206          0
            numpty                1          1         16         16          0
            numsiginfo            0          1        256        256          0
            tcpsndbuf         17856      17856    1720320    2703360          0
            tcprcvbuf         32768      32768    1720320    2703360          0
            othersockbuf       2232       2928    1126080    2097152          0
            dgramrcvbuf           0          0     262144     262144          0
            numothersock          1          3        120        120          0
            dcachesize            0          0    3409920    3624960          0
            numfile             189        189       9312       9312          0
            dummy                 0          0          0          0          0
            dummy                 0          0          0          0          0
            dummy                 0          0          0          0          0
            numiptent            10         10        128        128          0

The failcnt column is very important, it should contain only zeros; if it doesn't, this means that the vm needs more resources than are currently allocated to the vm. Open the vm's configuration file in /etc/vz/conf and raise the appropriate resource, then restart the vm.

To find out more about the vzctl command, run

man vzctl 


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By: wintel2006

I started to know openvz in the linux conference 2008, and I were pretty impressed by the features showed on the seminars. At that time I were trying to decide use xen or kvm to set up a cluster coldfusion server in my company, and finally I choose xen;

one of the key reason I choose xen is although openvz looks pretty amazing, the default file system for any guestOS is simfs, which I could not find any information about it. I would like to try that again if openvz support ext3,ext4 or any other common linux file system. (It is good to try the new virtual technology, but it is totally different story if you plan to use it in production environment. Again it is my personal opinion, and I do believe openvz is pretty good)

 By the way, if you do like to try openvz, Proxmox Virtual Environment (Proxmox VE, debian based OS) is a pretty good choice since it support both openvz and kvm, and also a web manager interface.