Commit 16450d30 authored by Iustin Pop's avatar Iustin Pop
Browse files

Document kernel selection method

This changelist add:
  - documentation on how to select the kernel and initrd (if needed) for
    instances
  - support in hypervisor.py for the initrd
  - adds note about internet-connectivity and debootstrap requirements
    for the minimal etch os
  - documentation on the miminum xenvg size

Reviewed-by: roman.marxer,ultrotter
parent 32ad0582
......@@ -88,8 +88,10 @@
It is advised to start with a clean, minimal install of the
operating system. The only requirement you need to be aware of
at this stage is to partition leaving enough space for a big
LVM volume group which will then host your instance
filesystems. The volume group name Ganeti 1.2 uses is
(<emphasis role="strong">minimum
<constant>20GiB</constant></emphasis>) LVM volume group which
will then host your instance filesystems. The volume group
name Ganeti 1.2 uses (by default) is
<emphasis>xenvg</emphasis>.
</para>
......@@ -101,7 +103,7 @@
</note>
<para>
While you can use an exiting system, please note that the
While you can use an existing system, please note that the
Ganeti installation is intrusive in terms of changes to the
system configuration, and it's best to use a newly-installed
system without important data on it.
......@@ -149,11 +151,42 @@
<formalpara><title>Debian</title>
<para>
Under Debian Etch or Sarge+backports you can install the
relevant xen-linux-system package, which will pull in both the
hypervisor and the relevant kernel.
relevant <literal>xen-linux-system</literal> package, which
will pull in both the hypervisor and the relevant kernel.
</para>
</formalpara>
<sect3>
<title>Selecting the instance kernel</title>
<para>
After you have installed xen, you need to tell Ganeti
exactly what kernel to use for the instances it will
create. This is done by creating a
<emphasis>symlink</emphasis> from your actual kernel to
<filename>/boot/vmlinuz-2.6-xenU</filename>, and one from
your initrd to
<filename>/boot/initrd-2.6-xenU</filename>. Note that if you
don't use an initrd for the <literal>domU</literal> kernel,
you don't need to create the initrd symlink.
</para>
<formalpara>
<title>Debian</title>
<para>
After installation of the
<literal>xen-linux-system</literal> package, you need to
run (replace the exact version number with the one you
have):
<screen>
cd /boot
ln -s vmlinuz-2.6.18-5-xen-686 vmlinuz-2.6-xenU
ln -s initrd.img-2.6.18-5-xen-686 initrd-2.6-xenU
</screen>
</para>
</formalpara>
</sect3>
</sect2>
<sect2>
......@@ -366,6 +399,10 @@ xen-br0 8000.0020fc1ed55d no eth0
<para><emphasis role="strong">Mandatory</emphasis> on all nodes.</para>
<note>
<simpara>The volume group is required to be at least
<constant>20GiB</constant>.</simpara>
</note>
<para>
If you haven't configured your LVM volume group at install
time you need to do it before trying to initialize the Ganeti
......@@ -448,6 +485,23 @@ tar xvf instance-debian-etch-0.1.tar
mv instance-debian-etch-0.1 debian-etch
</screen>
<para>
In order to use this OS definition, you need to have internet
access from your nodes and have <citerefentry>
<refentrytitle>debootstrap</refentrytitle>
<manvolnum>8</manvolnum> </citerefentry> installed on all the
nodes.
</para>
<formalpara>
<title>Debian</title>
<para>
Use this command on all nodes to install
<computeroutput>debootstrap</computeroutput>:
<screen>apt-get install debootstrap</screen>
</para>
</formalpara>
<para>
Alternatively, you can create your own OS definitions. See the
manpage
......
......@@ -133,6 +133,8 @@ class XenHypervisor(BaseHypervisor):
config = StringIO()
config.write("# this is autogenerated by Ganeti, please do not edit\n#\n")
config.write("kernel = '/boot/vmlinuz-2.6-xenU'\n")
if os.path.exists("/boot/initrd-2.6-xenU"):
config.write("ramdisk = '/boot/initrd-2.6-xenU'\n")
config.write("memory = %d\n" % instance.memory)
config.write("vcpus = %d\n" % instance.vcpus)
config.write("name = '%s'\n" % instance.name)
......
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