OpenVZ Virtuozzo Containers Wiki - User contributions [en]

Debian template creation

2007-04-25T09:04:38Z

Silverity: /* Fix SSH host keys */ fixed quotes for ssh-keygen

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.
<pre>
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
</pre>

=== 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]]

Debian template creation

2007-04-25T08:59:40Z

Silverity: /* Fix SSH host keys */

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]]