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Re: [libvirt] [PATCH] esx: Add vpx:// scheme to allow direct connection to a vCenter



2010/7/19 Daniel Veillard <veillard redhat com>:
> On Mon, Jul 19, 2010 at 01:26:10AM +0200, Matthias Bolte wrote:
>> Add a pointer to the primary context of a connection and use it in all
>> driver functions that don't dependent on the context type. This includes
>> almost all functions that deal with a virDomianPtr. Therefore, using
>> a vpx:// connection allows you to perform all the usual domain related
>> actions like start, destroy, suspend, resume, dumpxml etc.
>>
>> Some functions that require an explicitly specified ESX server don't work
>> yet. This includes the host UUID, the hostname, the general node info, the
>> max vCPU count and the free memory. Also not working yet are migration and
>> defining new domains.
>> ---
>>  docs/drvesx.html.in          |   21 +-
>>  src/esx/esx_driver.c         |  931 ++++++++++++++++++++++++------------------
>>  src/esx/esx_private.h        |    1 +
>>  src/esx/esx_storage_driver.c |   33 +-
>>  src/esx/esx_vmx.c            |    2 +
>>  src/libvirt.c                |    1 +
>>  6 files changed, 562 insertions(+), 427 deletions(-)
>>
>> diff --git a/docs/drvesx.html.in b/docs/drvesx.html.in
>> index e8cee77..1f2ae4e 100644
>> --- a/docs/drvesx.html.in
>> +++ b/docs/drvesx.html.in
>> @@ -4,13 +4,14 @@
>>      <p>
>>          The libvirt VMware ESX driver can manage VMware ESX/ESXi 3.5/4.0 and
>>          VMware GSX 2.0, also called VMware Server 2.0, and possibly later
>> -        versions.
>> +        versions. <span class="since">Since 0.8.3</span> the driver can also
>> +        connect to a VMware vCenter 2.5/4.0 (VPX).
>>      </p>
>>
>>
>>      <h2><a name="prereq">Deployment pre-requisites</a></h2>
>>      <p>
>> -        None. Any out-of-the-box installation of ESX/GSX should work. No
>> +        None. Any out-of-the-box installation of VPX/ESX(i)/GSX should work. No
>>          preparations are required on the server side, no libvirtd must be
>>          installed on the ESX server. The driver uses version 2.5 of the remote,
>>          SOAP based
>> @@ -27,10 +28,11 @@
>>          Some example remote connection URIs for the driver are:
>>      </p>
>>  <pre>
>> -esx://example.com                  (ESX over HTTPS)
>> -gsx://example.com                  (GSX over HTTPS)
>> -esx://example.com/?transport=http  (ESX over HTTP)
>> -esx://example.com/?no_verify=1     (ESX over HTTPS, but doesn't verify the server's SSL certificate)
>> +vpx://example-vcenter.com              (VPX over HTTPS)
>> +esx://example-esx.com                  (ESX over HTTPS)
>> +gsx://example-gsx.com                  (GSX over HTTPS)
>> +esx://example-esx.com/?transport=http  (ESX over HTTP)
>> +esx://example-esx.com/?no_verify=1     (ESX over HTTPS, but doesn't verify the server's SSL certificate)
>>  </pre>
>>      <p>
>>          <strong>Note</strong>: In contrast to other drivers, the ESX driver is
>> @@ -49,9 +51,9 @@ esx://example.com/?no_verify=1     (ESX over HTTPS, but doesn't verify the serve
>>  type://[username ]hostname[:port]/[?extraparameters]
>
>
>  May I suggest a small extra sentence here, explaining how to compose
> extraparameters ? User may find from lookuing above that they need to
> use:
>
>   arg=value
>
> but there is no indication on how to separate multiple parameter.

That's true. I'll add a sentence or two about that.

>>  </pre>
>>      <p>
> [...]
>> diff --git a/src/esx/esx_driver.c b/src/esx/esx_driver.c
>> index 33f421d..5922cb6 100644
>> --- a/src/esx/esx_driver.c
>> +++ b/src/esx/esx_driver.c
>> @@ -67,6 +67,11 @@ esxSupportsLongMode(esxPrivate *priv)
>>          return priv->supportsLongMode;
>>      }
>>
>> +    if (priv->host == NULL) {
>> +        /* FIXME: Currently no host for a vpx:// connection */
>> +        return esxVI_Boolean_False;
>> +    }
>> +
>
>  What about emitting an error in those cases ?

No error is reported here, because there is no error. I case you
connected to a vCenter there is currently no host object that could be
used to detect i686 vs x86_64. So the driver just pretends that x86_64
is not supported.

The same holds for the other places that are short-circuited like this
for a vpx:// connection.

> [...]
>> @@ -661,6 +729,11 @@ esxSupportsVMotion(esxPrivate *priv)
>>          return priv->supportsVMotion;
>>      }
>>
>> +    if (priv->host == NULL) {
>> +        /* FIXME: Currently no host for a vpx:// connection */
>> +        return esxVI_Boolean_False;
>> +    }
>> +
>
>  I feel ignorant here. I would assume that a vpx:// connection being to
> a vCenter vould allow to migrate, care to explain :-) ?

It will, but migration is tricky. Some more details first:

An ESX server has one Datacenter, this Datacenter contains one
ComputeResource and this ComputeResource has a single HostSystem
attached. Migration is performed between HostSystems in general. Given
two ESX connections the driver can easily determine the two involved
HostSystems.

A vCenter server can have multiple Datacenters, each Datacenter can
contain multiple ComputeResources. There also might by a special type
of ComputeResources, the ClusterComputeResource. A
ClusterComputeResource may have multiple HostSystems attached. To make
it more complex there is DRS. If DRS is enabled for a
ClusterComputeResource then the vCenter server will automatically
control the VirtualMachine to HostSystem mapping. In that case you can
migrate between ClusterComputeResources and the vCenter will select
the destination HostSystem for you.

But with the current vpx:// URI you specify the vCenter only, you
don't specify the Datacenter or the ComputeResource or the HostSystem
yet. Therefore, migration using a vpx:// URI doesn't work yet and I
simply short-circuited the VMotion check for a vpx:// connection for
now, effectively disabling migration for vpx:// connections.

I plan to model the Datacenter/ComputeResource/HostSystem selection
via the path part of the URI:
vpx://example-vcenter.com/datacenter1/cluster1/hostsystem1

This allows to omit the HostSystem part in case cluster1 has DRS enabled.

Migration is a complex topic, I decided to solve it with a later patch
and to do the simple things first :)

> [...]
>
>> @@ -2173,6 +2283,7 @@ esxDomainDumpXML(virDomainPtr domain, int flags)
>>      }
>>
>>      esxVI_String_Free(&propertyNameList);
>> +    esxVI_ObjectContent_Free(&datacenter);
>>      esxVI_ObjectContent_Free(&virtualMachine);
>>      VIR_FREE(datastoreName);
>>      VIR_FREE(directoryName);
>
>  I'm a bit suspicious, I see no virFree(datacenterName) here ... normal ?

Yes, it's obtained via esxVI_GetStringValue from the datacenter
object. The datacenter object owns the string and the string will be
freed when the datacenter object gets freed via
esxVI_ObjectContent_Free(&datacenter).

> Okay, overall a very large part of the patch is the change from
> priv->host to priv->primary, and there is still some TODOs without
> an error, I assume they will get fixed soon,

The "TODOs without an error" are the places where I decided to solve
the complexer parts in a separate patch later and to do the simple
things first.

>
>  based on this and after double checking the few points I raised, ACK :-)
>
>    thanks !
>
> Daniel
>

Thanks, pushed.

Matthias


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