This article is basicaly written for OpenVZ LiveCD and assumes that the reader only starts using OpenVZ.([[Download live CD]]) == Introduction ==So, as you probably know, OpenVZ allows the user to create '''[[VE''']]s - , or Virtual Environments, which seems seem very much

In the same way , a VE can be based on various [[OS template|OS (Operating System) '''templates''']]. On the LiveCD only Debian few minimaltemplate is OS templates are installed and it is used by defaultbecause of disk space limit. Each VE is indentified identified by its identification number -- a '''veidVEID'''. == VE creation ==So, how to create a VE with veid 1 VEID of 101 based on Debian template? Very easy. Just type the following commands in your

root@Knoppix:~# vzctl create 101 --ostemplate debian-3.1-i386-minimal

'''vzctl''' - is the tool that manages VEs. You can get the list of all created VEs on '''HN''' Look in <tt>/vz/template/cache/</tt> (CentOS LiveCD)or in <tt>/var/lib/vz/template/cache/</tt> (Hardware NodeKNOPPIX LiveCD) by '''vzlist''' commanddirectories for other OS templates available on LiveCD:

root@Knoppix# ls -1 /var/lib/vz/template/cache/centos-4-i386-minimal.tar.gzdebian-3.1-i386-minimal.tar.gzfedora-core-5-i386-minimal.tar.gz</pre> == List of VEs ==You can get the list of all created VEs on '''HN''' (Hardware Node) using '''vzlist''' command:~<pre># vzlist -a

1 101 - stopped - -

As you see, VE #1 101 is in stopped state now.  == Starting VE ==Let's start it:

root@Knoppix:~# vzctl start 1101

root@Knoppix:~# vzlist -a

1 101 5 running -

Five == Executing commands in VE ==From the "vzlist" command you see that 5 processes are running inside VE 101. (The "NPROC" field indicates the number of Processes, or PIDs, that are active in the VE-- not the number of Processors, but who are they? Beeing or CPUs.) Being on usual [[hardware node ]] you can use <code>ps </code> command to identify themthose,and the same command can be used here. The only difference is that this command should be called inside VE. 

root@Knoppix:~# vzctl exec 1 101 ps

root@Knoppix:~# vzctl enter 1101entered into VE 1101Knoppix:/#

Knoppix:/# useradd new-userKnoppix:/# passwd new-user

Knoppix:/# mkdir /home/new-userKnoppix:/# chown new-user /home/new-user/Knoppix:/# su new-userKnoppix:/$ cd ~Knoppix:~$ pwd

Knoppix:/#

Knoppix:/# exit

exited from VE 1101root@Knoppix:~#

I guess you've noted that there is not much soft in VE. It is because minimal template was used.But of course, you can install any soft in == Setting up VE by yourself. For example in Debian usual apt-get tool can be used.networking ==The only small problem is that all the packages should be downloaded from Internet so letLet's set up network networking in VE. 

root@Knoppix:~# echo 1 > /proc/sys/net/ipv4/ip_forwardroot@Knoppix:~# ifconfig venet0 uproot@Knoppix:~# vzctl set 1 101 --ipadd 10.1.1.1 --save

root@Knoppix:~# vzlist -a

1 101 4 running 10.1.1.1 -

Now your '''HN''' ([[Hardware Node) ]] can ping VE and VE can ping HN:

root@Knoppix:~# ping 10.1.1.1

root@Knoppix:~#root@Knoppix:~# vzctl exec 1 101 ping 192.168.0.244

root@Knoppix:~#

However, it isn't is not possible to ping other computers in the network: for it we need toset up NAT (Network Address Translation) and set the nameserver. 

root@Knoppix:~# iptables -t nat -A POSTROUTING -s 10.1.1.1 -o eth0 -j SNAT --to 192.168.0.244root@Knoppix:~# vzctl set 1 101 --nameserver 192.168.1.1 --save

Saved parameters for VE 1101root@Knoppix:~# vzctl exec 1 101 ping google.com

== Installing software inside VE ==I guess you've noted that there is not so many packages in VE. It is because minimal template was used.But of course, you can install any software in VE by yourself. For example, in Debian usual <tt>apt-get</tt> tool can be used. Now, for example, we can install gcc inside VE #1 101 for developing purposes:

root@Knoppix:~# vzctl enter 1101entered into VE 1101Knoppix:/#Knoppix:/# apt-get install gcc

Knoppix:/# exit

exited from VE 1101root@Knoppix#</pre> {{ Note|In the LiveCD environment, you may have to increase '''shmpages''' resource limit/barrier for the VE (read the next section) or you will run out of "disk space" when trying to install software }} == Resource limiting ==The very important feature of VE is that you can limit it by resources:~#CPU, memory, disk space.It is also performed via vzctl. For example to set '''shmpages''' (shared memory pages) barrier:limit youshould give this command:<pre>vzctl set 101 --shmpages 16384:16384 --save

The very important feature of VEs is that you can limit them by resources: cpu, memory, disk space.It's done by vzctl also. Crelayurrent Current usage/values and limits of memory -related resources can be veiwed viewed through'''<code>/proc/user_beancounters''' bc/VEID/resources</code> file:

root@Knoppix:~# cat /proc/bc/101/resources # or /proc/user_beancountersVersion: on 2.5 uid resource held maxheld barrier limit failcnt6.9 kernels 1: kmemsize 628209 976969 2752512 2936012 0

0: kmemsize 7843131 9967098 2147483647 2147483647 0 lockedpages 0 0 2147483647 2147483647 0 privvmpages 89600 127711 2147483647 2147483647 0 shmpages 63290 90159 2147483647 2147483647 0 dummy 0 0 2147483647 2147483647 0 numproc 73 78 2147483647 2147483647 0 physpages 85729 112341 2147483647 2147483647 0 vmguarpages 0 0 2147483647 2147483647 0 oomguarpages 85729 112341 2147483647 2147483647 1 numtcpsock 5 6 2147483647 2147483647 0 numflock 0 1 2147483647 2147483647 0 numpty 3 3 2147483647 2147483647 0 numsiginfo 0 3 2147483647 2147483647 0 tcpsndbuf 46620 48840 2147483647 2147483647 0 tcprcvbuf 81920 125476 2147483647 2147483647 0 othersockbuf 228660 339664 2147483647 2147483647 0 dgramrcvbuf 0 267484 2147483647 2147483647 0 numothersock 120 136 2147483647 2147483647 0 dcachesize 0 0 2147483647 2147483647 0 numfile 3111 3145 2147483647 2147483647 0 dummy 0 0 2147483647 2147483647 0 dummy 0 0 2147483647 2147483647 0 dummy 0 0 2147483647 2147483647 0 numiptent 15 15 2147483647 2147483647 0root@Knoppix:~#

Note, that if you have failcounters nonzero values in the last column, it means, that appropriate this VEexpirienced experienced a resource shortage. This is very common reason, why some applications application fail torun work in a VE. In this case you should increase limits/barriersaccordingly; see[[resource shortage]] for more info.

root@Knoppix:~# vzctl stop 1101

root@Knoppix:~# rm -rf /var/lib/vz/private/1 # THIS STEP IS TEMPORARY: http://bugzilla.openvz.org/show_bug.cgi?id=455root@Knoppix:~# vzctl destroy 1101Destroying VE private area: /var/lib/vz/private/1101

root@Knoppix:~#

== Links ==That's all you need to start playing with OpenVZ. Additional information can be found in man page on vzctl and at http://wiki.openvz.org/ . If you expirience experience some difficulties , contact us via http://forum.openvz.org/ . Templates and other tools at are available from http://download.openvz.org/ . [[Category: Live CD]]