Installing And Using OpenVZ On Ubuntu 8.10
Version 1.0
Author: Falko Timme
In this HowTo I will describe how to prepare an Ubuntu 8.10 server for OpenVZ. With OpenVZ you can create multiple Virtual Private Servers (VPS) on the same hardware, similar to Xen and the Linux Vserver project. OpenVZ is the open-source branch of Virtuozzo, a commercial virtualization solution used by many providers that offer virtual servers. The OpenVZ kernel patch is licensed under the GPL license, and the user-level tools are under the QPL license.
This howto is meant as a practical guide; it does not cover the theoretical backgrounds. They are treated in a lot of other documents in the web.
This document comes without warranty of any kind! I want to say that this is not the only way of setting up such a system. There are many ways of achieving this goal but this is the way I take. I do not issue any guarantee that this will work for you!
1 Preliminary Note
I'm using an x86_64 (amd64) system here. If you are on an i386 system, a few commands will be slightly different - I have added annotations to that parts.
2 Become root
Type
sudo su
to become root (or prepend all commands in this tutorial with the string sudo).
3 Change The Default Shell
/bin/sh is a symlink to /bin/dash, however we need /bin/bash, not /bin/dash. Therefore we do this:
ln -sf /bin/bash /bin/sh
4 Disable AppArmor
AppArmor is a security extension (similar to SELinux) that should provide extended security. In my opinion you don't need it to configure a secure system, and it usually causes more problems than advantages (think of it after you have done a week of trouble-shooting because some service wasn't working as expected, and then you find out that everything was ok, only AppArmor was causing the problem). Therefore I disable it.
We can disable it like this:
/etc/init.d/apparmor stop
update-rc.d -f apparmor remove
apt-get remove apparmor apparmor-utils
5 Installing OpenVZ
In order to install OpenVZ, we need to add the OpenVZ repository to our /etc/apt/sources.list:
vi /etc/apt/sources.list
[...] deb http://download.openvz.org/debian-systs lenny openvz [...] |
Run
wget -q http://download.openvz.org/debian-systs/dso_archiv_signing_key.asc -O- | apt-key add - && apt-get update
afterwards to download the key of that repository and update the package database.
To find the available OpenVZ packages (especially the OpenVZ kernel that we need to install), run
apt-cache search openvz
root@server1:~# apt-cache search openvz
vzctl - server virtualization solution - control tools
vzquota - server virtualization solution - quota tools
fzakernel-2.6.24-amd64 - OpenVZ - Meta kernel 2.6.246-fza-amd64 (2.6.24+ovz004.1dso6) on amd64
linux-patch-openvz - OpenVZ - server virtualization solution - Linux kernel patch
vzctl-ostmpl-debian-4.0-amd64-minimal - OpenVZ - OS Template debian-4.0-amd64-minimal
vzctl-ostmpl-debian-4.0-i386-minimal - OpenVZ - OS Template debian-4.0-i386-minimal
vzctl-ostmpl-debian-5.0-amd64-minimal - OpenVZ - OS Template debian-5.0-amd64-minimal
vzctl-ostmpl-debian-5.0-i386-minimal - OpenVZ - OS Template debian-5.0-i386-minimal
root@server1:~#
As you see, in my case the kernel is named fzakernel-2.6.24-amd64 (I'm on a 64bit Ubuntu 8.10), so I install it as follows:
apt-get install fzakernel-2.6.24-amd64
If you are on a i386 system, the package is named slightly different (probably fzakernel-2.6.24-i386).
Now open /boot/grub/menu.lst...
vi /boot/grub/menu.lst
... and make the OpenVZ kernel the default kernel. In my /boot/grub/menu.lst I have the following kernels...
[...] ## ## End Default Options ## title Ubuntu 8.10, kernel 2.6.27-7-server uuid a384f789-7b8b-4464-8340-f5fcc73ecc5b kernel /boot/vmlinuz-2.6.27-7-server root=UUID=a384f789-7b8b-4464-8340-f5fcc73ecc5b ro quiet splash initrd /boot/initrd.img-2.6.27-7-server quiet title Ubuntu 8.10, kernel 2.6.27-7-server (recovery mode) uuid a384f789-7b8b-4464-8340-f5fcc73ecc5b kernel /boot/vmlinuz-2.6.27-7-server root=UUID=a384f789-7b8b-4464-8340-f5fcc73ecc5b ro single initrd /boot/initrd.img-2.6.27-7-server title Ubuntu 8.10, kernel 2.6.24-6-fza-amd64 uuid a384f789-7b8b-4464-8340-f5fcc73ecc5b kernel /boot/vmlinuz-2.6.24-6-fza-amd64 root=UUID=a384f789-7b8b-4464-8340-f5fcc73ecc5b ro quiet splash initrd /boot/initrd.img-2.6.24-6-fza-amd64 quiet title Ubuntu 8.10, kernel 2.6.24-6-fza-amd64 (recovery mode) uuid a384f789-7b8b-4464-8340-f5fcc73ecc5b kernel /boot/vmlinuz-2.6.24-6-fza-amd64 root=UUID=a384f789-7b8b-4464-8340-f5fcc73ecc5b ro single initrd /boot/initrd.img-2.6.24-6-fza-amd64 title Ubuntu 8.10, memtest86+ uuid a384f789-7b8b-4464-8340-f5fcc73ecc5b kernel /boot/memtest86+.bin quiet ### END DEBIAN AUTOMAGIC KERNELS LIST |
... which means the OpenVZ kernel is the third kernel. Because counting starts with 0, I change the value of default to 2:
[...] default 2 [...] |
Now we install some OpenVZ user tools:
apt-get install vzctl vzquota
Open /etc/sysctl.conf and make sure that you have the following settings in it:
vi /etc/sysctl.conf
[...] net.ipv4.conf.all.rp_filter=1 net.ipv4.icmp_echo_ignore_broadcasts=1 net.ipv4.conf.default.forwarding=1 net.ipv4.conf.default.proxy_arp = 0 net.ipv4.ip_forward=1 kernel.sysrq = 1 net.ipv4.conf.default.send_redirects = 1 net.ipv4.conf.all.send_redirects = 0 net.ipv4.conf.eth0.proxy_arp=1 [...] |
If you need to modify /etc/sysctl.conf, run
sysctl -p
afterwards.
The following step is important if the IP addresses of your virtual machines are from a different subnet than the host system's IP address. If you don't do this, networking will not work in the virtual machines!
Open /etc/vz/vz.conf and set NEIGHBOUR_DEVS to all:
vi /etc/vz/vz.conf
[...] NEIGHBOUR_DEVS=all [...] |
Finally, reboot the system:
reboot
If your system reboots without problems, then everything is fine!
After the reboot, become root again:
sudo su
Run
uname -r
and your new OpenVZ kernel should show up:
root@server1:~# uname -r
2.6.24-6-fza-amd64
root@server1:~#
6 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.
In the
apt-cache search openvz
output (see the previous chapter) we had four Debian templates that we can install as follows (the amd64 templates are probably not available on an i386 host):
apt-get install vzctl-ostmpl-debian-4.0-amd64-minimal vzctl-ostmpl-debian-4.0-i386-minimal vzctl-ostmpl-debian-5.0-amd64-minimal vzctl-ostmpl-debian-5.0-i386-minimal
You can use one of these templates, but you can also find a list of precreated templates on http://wiki.openvz.org/Download/template/precreated.
I want to use Ubuntu 8.04 in my virtual machines, so I download an Ubuntu 8.04 template (a minimal Ubuntu 8.04 template in this case):
cd /var/lib/vz/template/cache
wget http://download.openvz.org/template/precreated/ubuntu-8.04-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 minimal Ubuntu 8.04 template, run:
vzctl create 101 --ostemplate ubuntu-8.04-amd64-minimal --config vps.basic
(To create a VPS from the vzctl-ostmpl-debian-4.0-i386-minimal template package, the command would be
vzctl create 101 --ostemplate debian-4.0-i386-minimal --config vps.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 213.191.92.86 --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
VEID NPROC STATUS IP_ADDR HOSTNAME
101 5 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
root@server1:~# vzctl exec 101 cat /proc/user_beancounters
Version: 2.5
uid resource held maxheld barrier limit failcnt
101: kmemsize 593615 1721162 11055923 11377049 0
lockedpages 0 0 256 256 0
privvmpages 2111 2491 65536 69632 0
shmpages 645 661 21504 21504 0
dummy 0 0 0 0 0
numproc 6 11 240 240 0
physpages 1124 1427 0 2147483647 0
vmguarpages 0 0 33792 2147483647 0
oomguarpages 1124 1427 26112 2147483647 0
numtcpsock 2 2 360 360 0
numflock 0 1 188 206 0
numpty 1 2 16 16 0
numsiginfo 0 2 256 256 0
tcpsndbuf 24640 24640 1720320 2703360 0
tcprcvbuf 32768 0 1720320 2703360 0
othersockbuf 4480 21760 1126080 2097152 0
dgramrcvbuf 0 8384 262144 262144 0
numothersock 3 7 120 120 0
dcachesize 53848 57912 3409920 3624960 0
numfile 184 254 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
root@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
7 Links
- OpenVZ: http://openvz.org
- Ubuntu: http://www.ubuntu.com
