Installing And Using OpenVZ On Debian Squeeze (AMD64) - Page 2
On this page
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 http://wiki.openvz.org/Download/template/precreated. For example, we can download a minimal Debian Squeeze template (x86_64) as follows:
cd /var/lib/vz/template/cache
wget http://download.openvz.org/template/precreated/contrib/debian-6.0-amd64-minimal.tar.gz
(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 192.168.0.101, 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 test.example.com --save
vzctl set 101 --ipadd 192.168.0.101 --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 145.253.2.75 --nameserver 8.8.8.8 --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
exit
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
root@server1:~# vzlist -a
CTID NPROC STATUS IP_ADDR HOSTNAME
101 8 running 192.168.0.101 test.example.com
root@server1:~#
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
server1:~#
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
4 Links
- OpenVZ: http://openvz.org/
- Debian: http://www.debian.org/
