Changes
→Modify the installation
[[Category: Templates]]
[[Category: Ubuntu]]
This article summarizes the experience of creating Ubunty Gutsy Gibbon (a.k.a. 7.10) template for OpenVZ.
=== debootstrap ===
You have to have a <code>debootstrap </code> working for Gutsy, i.e. you should have* <code>debootstrap </code> and its dependencies* <code>/usr/lib/debootstrap/scripts/gutsy </code> file
The simplest way to have it all is to work on an Ubunty Ubuntu Gutsy system (be it on a real machine or inside a VEcontainer). If you don't have <code>debootstrap </code> installed, this is the command to install it:
# apt-get install debootstrap
On a Gentoo Linux, <code>debootstrap</code> is also available, this is how you can install it:
# emerge \>=debootstrap-1.0.0
Note you need at least version 1.0.0, since earlier versions do not have Ubuntu scripts. So, possible you will first need to add it to package.keywords, like this:
# echo dev-util/debootstrap >> /etc/portage.package.keywords
On a Fedora system (at least Fedora 8, not sure about earlier versions):
# yum install debootstrap
=== vzctl ===
You need vzctl-3.0.19 22 or later to work with Ubuntu Gutsy Gibbon. If vzctl-3.0.18 or earlier is used, you will not be able to run your VEUbuntu Gutsy container. See {{bug|662}} for details. Note: Older versions of vzctl are working if you install <code>sysvinit</code> (which will remove <code>upstart</code>). The only problem I had was the network did not start, so I added "/etc/init.d/networking restart" to /etc/re.local.
== Creating template ==
=== Running debootstrap ===
Create some a working directory:
[HW]# mkdir gutsy-chroot
Run debootstrap to install a minimal Ubunty Gutsy system into that directory:
[HW]# debootstrap [--arch ''ARCH''] gutsy gutsy-chroot If ARCH of CT0 is equal to container, you can skip the --arch option, but if you need to build an OS template for another ''ARCH'', specify it explicitly:* for AMD64/x86_64, use <code>amd64</code>* for IA64, use <code>ia64</code>* for i386 <code>i386</code> === Preparing/starting a container ===
# echo "OSTEMPLATE=ubuntu-7.10" >> /etc/vz/conf/777.conf
=== Remove unneeded packages =Setting container IP address ====For the [[container]] to be able to download updates from the Internet, we need a valid IP address for it: # vzctl set 777 --ipadd x.x.x.x --save
==== Setting DNS server for the container ====For the [[container]] to be able to download updates from the Internet, we also need to specify a DNS for it: # vzctl set 777 --nameserver x.x.x.x --save Instead of <code>x.x.x.x</code>, specify the same IP that you have in your <code>/etc/resolv.conf</code>. ==== Starting container ====Now start the container: # vzctl start 777 === Modify the installation === You have to do some things in order to modify the installation to better suit the environment it will be run in (i.e. a container). First, enter a container: # vzctl enter 777 {{Warning|Do not run the commands below on the hardware node, they are only to be run within the container!}}==== Remove unneeded packages ==== Some packages does not make sense in a container, or are really optional. Remove those: [VEcontainer]# dpkg -P ubuntu-minimal wpasupplicant wireless-tools \
udev pcmciautils initramfs-tools volumeid console-setup \
xkb-data usbutils mii-diag alsa-base alsa-utils ethtool \
module-init-tools linux-sound-base console-tools \
console-terminus busybox-initramfs libvolume-id0 \
ntpdateeject libasound2 pciutils tasksel tasksel-data \ laptop-detect {{Note|On removing the deb-package "module-init-tools", a fake-modprobe is needed for IPv6 addresses, see below!}} Note that the above list of packages may be too extensive. Say, if you want to use <code>tasksel</code> tool, do not remove it — but then you have to let laptop-detect stay.
Clean up after udev:
[VEcontainer]# rm -fr /lib/udev
==== Disable getty ====On a usual Linux system, <code>getty </code> is running on a virtual terminals, which a VE container does not have. So, having <code>getty</code> running doesn't make sense; more to say, it complains it can not open terminal device and this clutters the logs.
First way:
[VEcontainer]# rm /etc/event.d/tty*
Second way:
[VEcontainer]# dpkg -P system-services Second way can be dangerous for future versions of <code>system-services</code>, but it's OK for now since the only service they carry is running <code>getty</code>s. ==== Set sane permissions for /root directory ====
=== Set sane permissions for /= Disable root directory login ====
[VEcontainer]# chmod 700 /usermod -L root
=== Disable root login = "fake-modprobe" needed for IPv6 addresses ====
[VEcontainer]# usermod ln -L roots /bin/true /sbin/modprobe
==== Get new security updates ==== [VEcontainer]# apt-get update && apt-get upgrade
<small>This didn't show anything for me, but might do something in the future.</small>
==== Install some more packages ====
[VEcontainer]# apt-get install ssh quota
Feel free to add packages which you want to have in a default template to this command.
==== Fix SSH host keys ====This is only useful if you installed SSH above. Each individual [[VEcontainer]] should have its own pair of SSH host keys. The code below will wipe out the existing SSH keys and instruct the newly-created [[VEcontainer]] to create new SSH keys on first boot.
<!-- please DO NOT remove <pre>...</pre> pair of tags below,
</pre>
==== Disable <code>sync()</code> for syslog ====
Turn off doing <tt>sync()</tt> on every write for <code>syslog</code>'s log files, to improve overall I/O performance.
<!-- DO NOT remove <pre> here, it's useful -->
<pre>[VEcontainer]# sed -i -e 's@\([[:space:]]\)\(/var/log/\)@\1-\2@' /etc/syslog.conf</pre>
==== Fix <code>/etc/mtab</code> ====
Link <code>/etc/mtab</code> to <code>/proc/mounts</code>, so <code>df</code> and friends will work:
[VEcontainer]# rm -f /etc/mtab [VEcontainer]# ln -s /proc/mounts /etc/mtab
After that, it would make sense to disable <code>mtab.sh</code> script which messes with <code>/etc/mtab</code>:
[VEcontainer]# update-rc.d -f mtab.sh remove ==== Disable some services ==== In most of the cases you don't want klogd to run -- the only exception is if you configure iptables to log some events -- so you can disable it: [container]# update-rc.d -f klogd remove ==== Hostname ====Set proper hostname: [container]# echo "localhost" > /etc/hostname ==== Set /etc/hosts ====
Remove DNS entries: [container]# > /etc/resolv.conf ==== Clean packages ====
After installing packages, you'll have some junk packages laying around in your cache. Since you don't want your template to have those, this command will wipe them out.
[VEcontainer]# apt-get clean
[VEcontainer]# echo "localhost" > cd /etcvar/hostnamelog [VEcontainer]# echo "127> messages; > auth.0log; > kern.log; > bootstrap.0log [container]# > dpkg.1 localhostlog; > syslog; > daemon.localdomain localhost" log; > apt/etc/hoststerm.log [container]# rm -f *.0 *.1
Now everything is done. Exit from the template and go back to the hardware node.
[VEcontainer]# umount exit == Preparing for and packing template cache == The following commands are to be run in the host system (i.e. not inside a container). We don't need an IP for the container anymore, and we definitely do not need it in template cache, so remove it: [HW]# vzctl set 777 --ipdel all --save Stop the container: [HW]# vzctl stop 777 Change dir to the container private: [HW]# cd /vz/private/777 Now create a cached OS tarball. In the command below, you'll want to replace <arch> with your architecture (i386, amd64, ia64, etc). '''Note the space and the dot at the end of the command'''. [HW]# tar --numeric-owner -czf /vz/template/cache/ubuntu-7.10-<arch>-minimal.tar.gz . Look at the resulting tarball to see its size is sane: # ls -lh /vz/template/cache -rw-r--r-- 1 root root 53M Nov 15 12:40 ubuntu-7.10-i386-minimal.tar.gz == Testing template cache ==We can now create a container based on the just-created template cache. Be sure to change <tt>i386</proctt> to your architecture just like you did when you named the tarball above. [VEHW]# exitvzctl create 123456 --ostemplate ubuntu-7.10-<arch>-minimal Now make sure that your new container it works: [HW]# vzctl start 123456 [HW]# vzctl exec 123456 ps axf
Other tests that could be done are:
[HW]# vzctl enter 123456
[container]# ps axf
[container]# mount
[container]# dpkg -l
[container]# logout
[HW]#
Feel free to do more tests.
== Update a VE OS Template Final cleanup ==Stop and remove the test container you just created: [HW]# vzctl stop 123456 Chroot to your debstrapped system[HW]# vzctl destroy 123456 [VE0HW]# cd <dir>; chroot rm -f /etc/vz/conf/123456./conf.destroyed
Finally, let's remove the container we used for OS template cache creation: Update and Install updates[HW]# vzctl destroy 777 [VEHW] # apt-get update && aptrm -get upgradef /etc/vz/conf/777.conf.destroyed