From 16450d30fc646747334d1fdfd5c359a20d6a56e5 Mon Sep 17 00:00:00 2001
From: Iustin Pop <iustin@google.com>
Date: Thu, 30 Aug 2007 09:35:39 +0000
Subject: [PATCH] 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
---
docs/install.sgml | 64 +++++++++++++++++++++++++++++++++++++++++++----
lib/hypervisor.py | 2 ++
2 files changed, 61 insertions(+), 5 deletions(-)
diff --git a/docs/install.sgml b/docs/install.sgml
index 789ee3770..ce9894ce9 100644
--- a/docs/install.sgml
+++ b/docs/install.sgml
@@ -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
diff --git a/lib/hypervisor.py b/lib/hypervisor.py
index 275050308..953eebf08 100644
--- a/lib/hypervisor.py
+++ b/lib/hypervisor.py
@@ -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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