[Libvirt-cim] [PATCH 0 of 3] (#3) [RFC] Add external migration checks

[Dan Smith]

HE> I looked a bit through the Migration Profile and found a class
HE> that I suggest to use for this functionality. That's the
HE> description of this class: "CIM_VirtualSystemMigrationSettingData
HE> defines the parameters to control a virtual system migration
HE> implementation, as managed by a
HE> CIM_VirtualSystemMigrationService. It is expected that a migration
HE> implementation will subclass this class to add
HE> implementation-specific migration options."  An instance of this
HE> class is transported to all CheckIsVSMigratable...() and
HE> MigrateVSTo...() via the MigrationSettingData parameter. So we
HE> stay absolutely conform to the Migration Profile. The Xen and KVM
HE> subclasses can check properties, that are well know to cause
HE> migration problems.

This is what I did.  I extended Xen_MigrationSettingData to include
the CheckParameters[] property, which is what I pass to the check
program.  There are no additional arguments to either of the CIM
methods, and this extra property of the SettingData is optional.

HE> Your approach of letting the client parameterize scripts through
HE> this class might look like this: [Description("An array containing
HE> the scripts to be executed as part of the check, if the migration
HE> is possible.")]  string ScriptsToExecute[]; [Description("An array
HE> containing the parameters given as input to the scripts defined by
HE> ScriptsToExecute. Each entry in this array is related to the same
HE> array entry in ScriptToExecute. A list of parameters for one
HE> script is divided by space characters.")]  string
HE> ScriptsParameterList[];

Choosing the external checks to run does two things: (1) It means that
the client must know which checks are available on the host, and (2)
it means that the client must change if the system administrator
changes the name of the check on disk.

Giving the client visibility and control over what we run and where
seems to (1) be more of a security risk, and (2) be too specific.
What I have now is less of "run command A with argument B" and more of
"Here is some information I have that should help determine if a
migration can succeed".  I think that the latter is more generally
applicable.  However, if others feel strongly, we can change this to a
list of programs and a list of arguments.

Thanks Heidi!

-- 
Dan Smith
IBM Linux Technology Center
Open Hypervisor Team
email: danms at us.ibm.com
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 188 bytes
Desc: not available
URL: <http://listman.redhat.com/archives/libvirt-cim/attachments/20080313/e2c4115a/attachment.sig>