Commit 061640c7 authored by Hrvoje Ribicic's avatar Hrvoje Ribicic

Update Xen documentation in install.rst

The Xen documentation in install.rst was out of date, describing
xm-specific changes at the point where 2.12 is mostly used with xl.
This patch removes xm-specific migration steps, references the official
Xen wiki instead of replicating information from it, removes the
VNC setup settings that are outdated for xl and probably for xm, and
slightly rewrites the documentation.
Signed-off-by: default avatarHrvoje Ribicic <>
Reviewed-by: default avatarKlaus Aehlig <>
parent 841d2b8f
......@@ -162,54 +162,24 @@ kernels. For KVM no reboot should be necessary.
Xen settings
It's recommended that dom0 is restricted to a low amount of memory
(512MiB or 1GiB is reasonable) and that memory ballooning is disabled in
the file ``/etc/xen/xend-config.sxp`` by setting the value
``dom0-min-mem`` to 0, like this::
Depending on which toolstack you are using, the hypervisor parameter
``xen_cmd`` has to be set to the matching value, either ``xm`` or
(dom0-min-mem 0)
Some useful best practices for Xen are to restrict the amount of memory
dom0 has available, and pin the dom0 to a limited number of CPUs.
Instructions for how to achieve this for various toolstacks can be found
on the Xen wiki_.
For optimum performance when running both CPU and I/O intensive
instances, it's also recommended that the dom0 is restricted to one CPU
only. For example you can add ``dom0_max_vcpus=1,dom0_vcpus_pin`` to your
kernels boot command line and set ``dom0-cpus`` in
``/etc/xen/xend-config.sxp`` like this::
.. _wiki:
(dom0-cpus 1)
It is recommended that you disable xen's automatic save of virtual
It is recommended that you disable Xen's automatic save of virtual
machines at system shutdown and subsequent restore of them at reboot.
To obtain this make sure the variable ``XENDOMAINS_SAVE`` in the file
``/etc/default/xendomains`` is set to an empty value.
If you want to use live migration make sure you have, in the xen config
file, something that allows the nodes to migrate instances between each
other. For example:
.. code-block:: text
(xend-relocation-server yes)
(xend-relocation-port 8002)
(xend-relocation-address '')
(xend-relocation-hosts-allow '^192\\.0\\.2\\.[0-9]+$')
The second line assumes that the hypervisor parameter
``migration_port`` is set 8002, otherwise modify it to match. The last
line assumes that all your nodes have secondary IPs in the network, adjust it accordingly to your setup.
If you want to run HVM instances too with Ganeti and want VNC access to
the console of your instances, set the following two entries in
.. code-block:: text
(vnc-listen '') (vncpasswd '')
You need to restart the Xen daemon for these settings to take effect::
$ /etc/init.d/xend restart
You may need to restart the Xen daemon for some of these settings to
take effect. The best way to do this depends on your distribution.
Selecting the instance kernel
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