Synnefo » snf-ganeti

Global hypervisor parameters

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Current State and shortcomings

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Currently all hypervisor parameters are modifiable both globally

(cluster level) and at instance level. However, there is no other

framework to held hypervisor-specific parameters, so if we want to add

a new class of hypervisor parameters that only makes sense on a global

level, we have to change the hvparams framework.

Proposed changes

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We add a new (global, not per-hypervisor) list of parameters which are

not changeable on a per-instance level. The create, modify and query

instance operations are changed to not allow/show these parameters.

Furthermore, to allow transition of parameters to the global list, and

to allow cleanup of inadverdently-customised parameters, the

``UpgradeConfig()`` method of instances will drop any such parameters

from their list of hvparams, such that a restart of the master daemon

is all that is needed for cleaning these up.

Also, the framework is simple enough that if we need to replicate it

at beparams level we can do so easily.

The second line assumess 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

            <term>chroot</term>

            <listitem>

              <para>

                a simple chroot manager that starts chroot based on a

                script at the root of the filesystem holding the

                chroot

          <varlistentry>

        The <option>--hypervisor-parameters</option> option allows you

        to set default hypervisor specific parameters for the

        cluster. The format of this option is the name of the

        hypervisor, followed by a colon and a comma-separated list of

        key=value pairs. The keys available for each hypervisors are

        detailed in the <citerefentry>

        <refentrytitle>gnt-instance</refentrytitle>

        <manvolnum>8</manvolnum> </citerefentry> man page, in the

        <command>add</command> command plus the following parameters

        which are only configurable globally (at cluster level):

        <variablelist>

          <varlistentry>

            <term>migration_port</term>

            <listitem>

              <simpara>Valid for the Xen PVM and KVM hypervisors.</simpara>

              <para>

                This options specifies the TCP port to use for

                live-migration. For Xen, the same port should be

                configured on all nodes in

                the <filename>/etc/xen/xend-config.sxp</filename>

                file, under the

                key <quote>xend-relocation-port</quote>.

              </para>

            </listitem>

          </varlistentry>

        </variablelist>

      </para>

      <para>