On 02/28/2012 02:49 PM, Jiri Denemark wrote:
> This hook is called during the Prepare phase on destination host and may
> be used for changing domain XML.
> ---
> docs/hooks.html.in | 35 +++++++++++++++++++++++------------
> src/qemu/qemu_migration.c | 40 ++++++++++++++++++++++++++++++++++++++++
> src/util/hooks.c | 3 ++-
> src/util/hooks.h | 1 +
> 4 files changed, 66 insertions(+), 13 deletions(-)
>
> diff --git a/docs/hooks.html.in b/docs/hooks.html.in
> index 890359e..6c82c6d 100644
> --- a/docs/hooks.html.in
> +++ b/docs/hooks.html.in
> @@ -120,6 +120,16 @@
> called again, <span class="since">since 0.9.0</span>, to allow
> any additional resource cleanup:<br/>
> <pre>/etc/libvirt/hooks/qemu guest_name release end -</pre></li>
> + <li><span class="since">Since 0.9.11</span>, the qemu hook script
> + is also called at the beginning of incoming migration. It is called
> + as: <pre>/etc/libvirt/hooks/qemu guest_name migrate begin -</pre>
> + with domain XML sent to standard input of the script. In this case,
> + the script acts as a filter and is supposed to modify the domain
> + XML and print it out on its standard output. Empty output is
> + identical to copying the input XML without changing it. In case the
> + script returns failure or the output XML is not valid, incoming
> + migration will be canceled. This hook may be used to, e.g., change
I think this reads better as:
s/used to, e.g., change/used, e.g., to change/
> + location of disk images for incoming domains.</li>
> </ul>
>
> <h5><a name="lxc">/etc/libvirt/hooks/lxc</a></h5>
> @@ -161,19 +171,20 @@
> source and destination hosts:</p>
> <ol>
> <li>At the beginning of the migration, the <i>qemu</i> hook script on
> - the <b>destination</b> host is executed with the "start"
> - operation.<br/><br/></li>
> - <li>If this hook script returns indicating success (error code 0), the
> - migration continues. Any other return code indicates failure, and
> - the migration is aborted.<br/><br/></li>
> - <li>The QEMU guest is then migrated to the destination host.<br/>
> - <br/></li>
> + the <b>destination</b> host is executed with the "migrate"
> + operation.</li>
> + <li>Before QEMU process is spawned, the two operations ("prepare" and
> + "start") called for domain start are executed on
> + <b>destination</b> host.</li>
> + <li>If any of these hook script executions returns indicating success
> + (error code 0), the migration continues. Any other return code
> + indicates failure, and the migration is aborted.</li>
This reads awkwardly - it makes it sound like 'prepare' exiting with 0
makes the overall operation succeed even if 'start' exits with non-zero.
I'd change it to:
If both of these hook script executions exit successfully (exit status
0), the migration continues. Any other exit code indicates failure, and
the migration is aborted.
> @@ -1150,6 +1152,43 @@ qemuMigrationPrepareAny(struct qemud_driver *driver,
> goto cleanup;
> }
>
> + /* Let migration hook filter domain XML */
> + if (virHookPresent(VIR_HOOK_DRIVER_QEMU)) {
> + char *xml = virDomainDefFormat(def, VIR_DOMAIN_XML_SECURE);
> + int hookret;
> +
> + hookret = virHookCall(VIR_HOOK_DRIVER_QEMU, def->name,
> + VIR_HOOK_QEMU_OP_MIGRATE, VIR_HOOK_SUBOP_BEGIN,
> + NULL, xml, &xmlout);
Needs to check for xml being NULL on OOM before virHookCall.
ACK with those issues fixed.
--
Eric Blake eblake@xxxxxxxxxx +1-919-301-3266
Libvirt virtualization library http://libvirt.org
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