Talk:UBC secondary parameters

2007-06-05T09:46:00Z

Merlin83b:

From the privvmpages section:

“Since the memory accounted into privvmpages may not be actually used, the sum of current privvmpages values for all Virtual Environments may exceed the RAM and swap size of the computer.
...
Total privvmpages should match the physical resources of the computer.”

This seems contradictory. [[User:Merlin83b|Merlin83b]] 05:46, 5 June 2007 (EDT)

Debian template creation

2007-05-10T09:42:11Z

Merlin83b: Make SSH section cut and pasteable

These are rough instructions of how to manually create basic Debian Etch (4.0) template cache, which can be used to create OpenVZ [[VE]]s based on Debian Etch (4.0).

'''Notes:'''
* You shouldn't be running as root, but as a user that is permitted to use sudo instead. It's a dangerous idea, run as root at your peril.
* Anywhere you see <tt>/vz</tt>, you might really need to use <tt>/var/lib/vz</tt> instead, especially on a Debian Etch host.
* Anywhere you see <tt>http://debian.osuosl.org/debian/</tt>, you can substitute your favorite Debian mirror. ([http://www.debian.org/mirror/list List of official Debian Mirrors])

== Prerequisites ==
You need to have a working copy of <tt>debootstrap</tt> running on your hardware node.

For Debian:
sudo apt-get install debootstrap

For Gentoo:
sudo emerge debootstrap

For other distros you might need to install it from sources, or search for an appropriate package for your distribution. An RPM is available on the [http://forum.openvz.org/index.php?t=tree&th=142&mid=584 OpenVZ Forum].

== Bootstrapping Debian ==
This will download Debian Etch to a temporary location on your server. Specify your architecture instead of <tt>i386</tt> if you're using something other than i386/x86. For example, for AMD64/x86_64, use <tt>amd64</tt> or for ia64, use <tt>ia64</tt>. We use VE ID of 777 for this example; surely it can be any other unused ID.
sudo debootstrap --arch i386 etch /vz/private/777 http://debian.osuosl.org/debian/

== Preparing and starting the VE ==

=== Setting VE config ===
First, we need a config for the [[VE]]:
sudo vzctl set 777 --applyconfig vps.basic --save

=== Setting VE OSTEMPLATE ===
Also, we need <tt>OSTEMPLATE</tt> to be set in VE configuration file, for the [[vzctl]] to work properly.

sudo sh -c 'echo "OSTEMPLATE=debian-4.0" >> /etc/vz/conf/777.conf'

=== Setting VE IP address ===
For the [[VE]] to be able to download updates from the Internet, we need a valid IP address for it:
sudo vzctl set 777 --ipadd x.x.x.x --save

{{Note|if you use private IP for the VE, you have to set up NAT as described in [[Using NAT for VE with private IPs]].}}

=== Setting DNS server for VE ===
For the [[VE]] to be able to download updates from the Internet, we also need to specify a DNS for it:
sudo vzctl set 777 --nameserver x.x.x.x --save

=== Starting VE ===
Now start the VE:
sudo vzctl start 777

== Customizing the installation ==
A few things need to be done inside a newly created VE for it to become suitable for OpenVZ. All those things are done inside the VE, so first command is:
sudo vzctl enter 777
export PATH=/sbin:/usr/sbin:/bin:/usr/bin

{{Note|'''Warning!''' Do not run the commands below on the hardware node, they are only to be run within the VE!}}

=== Set Debian repositories ===
cat <<EOF > /etc/apt/sources.list
deb http://debian.osuosl.org/debian/ etch main contrib
deb http://security.debian.org etch/updates main contrib
EOF

=== Get new security updates ===
apt-get update
apt-get upgrade

=== Install some more packages ===
Installing packages could be an interactive process so the system might ask some questions. You can install more packages if you'd like. For example:
apt-get install ssh quota

=== Set sane permissions for <tt>/root</tt> directory ===
chmod 700 /root

=== Disable root login ===
This will disable root login by default.
usermod -L root

=== Disable getty ===
Disable running <tt>getty</tt>s on terminals as a VE does not have any:
sed -i -e '/getty/d' /etc/inittab

=== Disable <tt>sync()</tt> for syslog ===
Turn off doing <tt>sync()</tt> on every write for <tt>syslog</tt>'s log files, to improve I/O performance:
sed -i -e 's@$[[:space:]]$$/var/log/$@\1-\2@' /etc/syslog.conf

=== Fix <tt>/etc/mtab</tt> ===
Link <tt>/etc/mtab</tt> to <tt>/proc/mounts</tt>, so <tt>df</tt> and friends will work:
rm -f /etc/mtab
ln -s /proc/mounts /etc/mtab

=== Remove some unneeded packages ===
If you have any packages you'd like to remove, now's the time for it. Here's an example:
dpkg --purge modutils ppp pppoeconf pppoe pppconfig

=== Disable services ===
Do not start some services, stick to bare minimum:
update-rc.d -f klogd remove
update-rc.d -f quotarpc remove
update-rc.d -f exim4 remove
update-rc.d -f inetd remove

=== Fix SSH host keys ===
This is only useful if you installed SSH. Each individual [[VE]] should have its own pair of SSH host keys. The code below will wipe out the existing SSH keys and instruct the newly-created [[VE]] to create new SSH keys on first boot.
rm -f /etc/ssh/ssh_host_*
cat << EOF > /etc/rc2.d/S15ssh_gen_host_keys
#!/bin/bash
ssh-keygen -f /etc/ssh/ssh_host_rsa_key -t rsa -N ''
ssh-keygen -f /etc/ssh/ssh_host_dsa_key -t dsa -N ''
rm -f \$0
EOF
chmod a+x /etc/rc2.d/S15ssh_gen_host_keys

=== 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.
apt-get clean

Now everything is done. Exit from the template and go back to the hardware node.
exit

== Preparing for and packing template cache ==

We don't need an IP for the VE anymore, and we definitely do not need it in template cache, so remove it:
sudo vzctl set 777 --ipdel all --save

Also, remove DNS server and search domain information from ''/etc/resolv.conf'' file '''in VE''':
sudo nano /vz/private/777/etc/resolv.conf

Stop the VE:
sudo vzctl stop 777

Go to the VE directory:
cd /vz/private/777

Now create a cached OS tarball. In the command below, you'll want to replace <tt>i386</tt> with your architecture (i386, amd64, ia64, etc).
sudo tar -zcf /vz/template/cache/debian-4.0-i386-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 51M Apr 10 03:16 debian-4.0-i386-minimal.tar.gz

== Checking if template cache works ==
We can now create a VE based on the just-created template cache. Be sure to change <tt>i386</tt> to your architecture just like you did when you named the tarball above.
sudo vzctl create 123456 --ostemplate debian-4.0-i386-minimal

Now make sure that it works:
sudo vzctl start 123456
sudo vzctl exec 123456 ps ax

You should see that a few processes are running.

== Final cleanup ==
Stop and remove the test VE you just created:
sudo vzctl stop 123456
sudo vzctl destroy 123456
sudo rm /etc/vz/conf/123456.conf.destroyed

Finally, let's remove the VE we used for OS template cache creation:
sudo vzctl destroy 777
sudo rm /etc/vz/conf/777.conf.destroyed

[[Category: HOWTO]]
[[Category: Templates]]

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Talk:UBC secondary parameters

Debian template creation