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[Libvir] Supporting new Xen 3.0.3 blktap backend for file devices
by Daniel P. Berrange 06 Oct '06

06 Oct '06

When defining a guest's block device in the libvirt XML we currently allow the dev to be backed by either a file or block device in the host system. This is done by specifying the 'type' attribute when defing the block device XML. eg <disk type='file'> Or <disk type='block'> This is all fine & dandy for Xen 3.0.2, but in 3.0.3 we now have a choice of drivers for the 'file' backed block devices. We can either use the traditional loopback mounted system, or the new blktap system. To complicate things further still, blktap itself has man different drivers - one uses a raw file with Async-IO, another uses the QCow sparse format with AIO, and all sort of other possibilities are available... This means the easy option of just making all file devices use blktap in 3.0.3 is not practical. This in turns means we need to come up with a way to express the new driver methods in libvirt XML. There are a few options I can think of : - Allow more values in the 'type' attribute, eg file, block, blktap:aio, blktap:qcow, etc. This feels wrong because the blktap:* entries are really still 'file' types. - Introduce a new attribute 'driver' where you can specify 'loop', 'blktap:aio', 'blktap:qcow', etc - Introduce a new element 'driver' where you can specify the same <disk type="file"> <driver type='blktap:aio'/> </disk> - Same as above, but normalize the driver type further <disk type="file"> <driver type='blktap' backend='aio' /> </disk> My preference is probably option 3 or 4. Dan. -- |=- Red Hat, Engineering, Emerging Technologies, Boston. +1 978 392 2496 -=| |=- Perl modules: http://search.cpan.org/~danberr/ -=| |=- Projects: http://freshmeat.net/~danielpb/ -=| |=- GnuPG: 7D3B9505 F3C9 553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505 -=|

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Re: [Libvir] Xen Routed
by Daniel P. Berrange 04 Oct '06

04 Oct '06

On Wed, Oct 04, 2006 at 08:09:27AM -0600, Nick Devito wrote: > On Wed, 2006-10-04 at 14:06 +0100, Daniel P. Berrange wrote: > > On Tue, Oct 03, 2006 at 07:15:23PM -0700, Sargun Dhillon wrote: > > > Does the XML file format support routed? > > > If so, what would the <interface> clause look like? > > > > I'm not familiar with the way routed networking is setup with Xen. If you > > can provide the example VIF device config params from /etc/xen/<some guest> > > which are needed for routing I'll check if they map through to libvirt > > XML format in neccessary manner. > > > Xen routed requires the ip= configuration variable, and, I think thats > it. I don't see any reason why it shouldn't work correctly. Ok, looking at the XML parsing routines we don't currently support the 'ip' property. Fortunately, it looks as if one of Michel Ponceau's patches from a thread last week ought to solve this problem, so we ought to be able to get this working for next release. Regards, Dan. -- |=- Red Hat, Engineering, Emerging Technologies, Boston. +1 978 392 2496 -=| |=- Perl modules: http://search.cpan.org/~danberr/ -=| |=- Projects: http://freshmeat.net/~danielpb/ -=| |=- GnuPG: 7D3B9505 F3C9 553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505 -=|

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[Libvir] Xen Routed
by Sargun Dhillon 04 Oct '06

04 Oct '06

Does the XML file format support routed? If so, what would the <interface> clause look like? -- Sargun Dhillon President Atarack Communications, Inc. (925)-202-9485

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[Libvir] Problem with hypercall
by Jim Fehlig 02 Oct '06

02 Oct '06

Stumbled across a problem trying to list domains with libvirt-0.1.5. Using virsh I get errors such as xen81:/tests/jim # virsh list Id Name State ---------------------------------- 0 Domain-0 running libvir: Xen Daemon error : GET operation failed: No such domain 16 xm shows xen81:/tests/jim # xm list Name ID Mem(MiB) VCPUs State Time(s) Domain-0 0 2048 4 r----- 815825.8 vm1 1 512 2 -b---- 0.3 I found that the buffer provided for XEN_V1_OP_GETDOMAININFOLIST hypercall differs slightly from the buffer in xen/dom0_ops.h. Attached is a patch against current cvs that works for me, but I'm not familiar with this part of the code so not sure if this is the proper fix. I'm using xen 3.0.2 that shipped with SLES10. Regards, Jim

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[Libvir] Proposal for virtual devices described in XML
by michel.ponceau＠bull.net 02 Oct '06

02 Oct '06

Proposal modified after comments from Daniel P. Berrange: /* Create a virtual device attachment to backend */ int virDomainAttachDevice(virDomainPtr domain, char *xml); /* Destroy a virtual device attachment to backend */ int virDomainDetachDevice(virDomainPtr domain, char *xml); /* @domain: pointer to domain object * @xml: pointer to XML description of one device * Returns 0 in case of success, -1 in case of failure. */ The XML would be in same form as the part of domain description for a single device, either <disk.../disk> or <interface.../interface>. In Detach function, the device is identified by its target name for "disk", and its MAC address for "interface". When the MAC address has not been assigned by Libvirt user at device creation, it must be retrieved from Xen using virDomainGetXMLDesc function.

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[Libvir] Release of libvirt-0.1.7
by Daniel Veillard 29 Sep '06

29 Sep '06

Is available on ftp://libvirt.org/libvirt/ It's 0.1.6 with the fixes for the 2 bugs that Daniel Berrange fixed yesterday: - failure of domain info when using the hypervisor on 32 bits with 3.0.3 - the memory corrption which can happen when reading vCPU info from xend Daniel -- Red Hat Virtualization group http://redhat.com/virtualization/ Daniel Veillard | virtualization library http://libvirt.org/ veillard(a)redhat.com | libxml GNOME XML XSLT toolkit http://xmlsoft.org/ http://veillard.com/ | Rpmfind RPM search engine http://rpmfind.net/

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Re: [Libvir] Proposal for virtual devices described in XML
by michel.ponceau＠bull.net 28 Sep '06

28 Sep '06

When specified at device creation, vifname is put in XenStore directory /local/domain/0/backend/vif/<domID>/<vif_number>. All vifnames used in a domain are returned by Get "/xend/domain/<domID>?detail=1" and converted into XML "target" by virDomainGetXMLDesc. For convenience, we could force the vifname, either at domain creation or in Attach, and ignore any "target" in "interface", except for Detach. The vifname value could be the sequence number of network device creation in domain (for Xen, it would be equal to vif number). Veuillez répondre à "Daniel P. Berrange" <berrange(a)redhat.com> Pour : michel.ponceau(a)bull.net cc : libvir-list(a)redhat.com Objet : Re: [Libvir] Proposal for virtual devices described in XML On Wed, Sep 27, 2006 at 05:21:33PM +0200, michel.ponceau(a)bull.net wrote: > After comments from Daniel P. Berrange and from Bull people, my proposal > is reduced to following 2 functions: > > /* Create a virtual device attachment to backend */ > int virDomainAttachDevice(virDomainPtr domain, char *xml); This is definitely a good way forward - it lets us re-use the existing code for parsing device descriptions very easily. > /* Destroy a virtual device attachment to backend */ > int virDomainDetachDevice(virDomainPtr domain, char *xml); > /* @domain: pointer to domain object > * @xml: pointer to XML description of one device > * Returns 0 in case of success, -1 in case of failure. */ I was wondering whether we need to have the full XML block passed in for detaching devices. Perhaps it is sufficient to just pass i nthe target name of the device. Then again, some implementations may prefer to have the full XML blob available to allow greater sanity checking when detaching, so its probably worth while. > The XML would be in same form as the part of domain description for a > single device, either <disk.../disk> or <interface.../interface>. Very nice. > The device is identified by its target name. This attribute is optional > for "interface" in domain description, but would become mandatory in > Attach/Detach description. It is not yet processed in Libvirt-0.1.6 source > xml.c (function virDomainParseXMLIfDesc). I have successfully tried the attached patch, which tranlates "target" > into Xen "vifname". (It processes "ip" attribute in same way, but my try > failed, maybe because address value was invalid for Xen). I'm not sure I like the idea of having to explicitly set a vif name for every guest NIC we define - principally because there's no straightforward way for a user of this API to determine what VIF names are already in use, vs free. It also seems XenD does not tell us what the vifname for running domains are - although I think the info is in xenstore somewhere. I can see why we need the vifname to detach the device though. If we can find a way to fill in the vifname when dumping the XML, then this would let a caller uniquely identify an existing device, without us requireing that vifnames are used when creating a domain/attaching a new device (& thus let Xen still auto-allocate them) Regards, Dan. -- |=- Red Hat, Engineering, Emerging Technologies, Boston. +1 978 392 2496 -=| |=- Perl modules: http://search.cpan.org/~danberr/ -=| |=- Projects: http://freshmeat.net/~danielpb/ -=| |=- GnuPG: 7D3B9505 F3C9 553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505 -=|

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[Libvir] Proposal for virtual devices described in XML
by michel.ponceau＠bull.net 28 Sep '06

28 Sep '06

My try of "ip" attribute failed because of a bug in patch. With this corrected file, it works as well as "target". Pour : libvir-list(a)redhat.com cc : Objet : Proposal for virtual devices described in XML After comments from Daniel P. Berrange and from Bull people, my proposal is reduced to following 2 functions: /* Create a virtual device attachment to backend */ int virDomainAttachDevice(virDomainPtr domain, char *xml); /* Destroy a virtual device attachment to backend */ int virDomainDetachDevice(virDomainPtr domain, char *xml); /* @domain: pointer to domain object * @xml: pointer to XML description of one device * Returns 0 in case of success, -1 in case of failure. */ The XML would be in same form as the part of domain description for a single device, either <disk.../disk> or <interface.../interface>. The device is identified by its target name. This attribute is optional for "interface" in domain description, but would become mandatory in Attach/Detach description. It is not yet processed in Libvirt-0.1.6 source xml.c (function virDomainParseXMLIfDesc). I have successfully tried the attached patch, which tranlates "target" into Xen "vifname". (It processes "ip" attribute in same way, but my try failed, maybe because address value was invalid for Xen).

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[Libvir] virDomainDestroy not synchronous?
by Lon Hohberger 27 Sep '06

27 Sep '06

i686 libvirt-0.1.5-3 xen-3.0.2-33 Code: domain_desc = virDomainGetXMLDesc(vdp, 0); response = virDomainDestroy(vdp); if (response == 0 && domain_desc) { /* sleep(3); */ virDomainCreateLinux(vp, domain_desc, 0); free(domain_desc); } If I add the 'sleep()', the domain dies and virDomainCreateLinux() fails with the following error: libvir: Xen Daemon error : POST operation failed: No such domain futon1 Failed to get devices for domain futon1 That really doesn't bother me, and it's likely my fault anyway (it's not a fully configured domain; it's a dom-U sitting in the anaconda install screen). Of course, it's moot if we get a guaranteed synchronous reboot flag for virDomainReboot()... hint hint ;) What bothers me is that if I *don't* put the sleep in, the domain never actually gets destroyed. In this particular case, the domain is still sitting at the anaconda install screen; all I have to do is reconnect using xm console. If I only do a virDomainDestroy(), the domain gets destroyed. So, it looks like like the virDomainCreateLinux() cancels the destroy request before it can be completed. This makes it look like that the destroy request is not synchronous, and/or the result of the operation is not guaranteed (only that the request was made). Is it supposed to work this way, or is this a bug/problem? -- Lon

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[Libvir] Proposal for virtual devices described in XML
by michel.ponceau＠bull.net 27 Sep '06

27 Sep '06

After comments from Daniel P. Berrange and from Bull people, my proposal is reduced to following 2 functions: /* Create a virtual device attachment to backend */ int virDomainAttachDevice(virDomainPtr domain, char *xml); /* Destroy a virtual device attachment to backend */ int virDomainDetachDevice(virDomainPtr domain, char *xml); /* @domain: pointer to domain object * @xml: pointer to XML description of one device * Returns 0 in case of success, -1 in case of failure. */ The XML would be in same form as the part of domain description for a single device, either <disk.../disk> or <interface.../interface>. The device is identified by its target name. This attribute is optional for "interface" in domain description, but would become mandatory in Attach/Detach description. It is not yet processed in Libvirt-0.1.6 source xml.c (function virDomainParseXMLIfDesc). I have successfully tried the attached patch, which tranlates "target" into Xen "vifname". (It processes "ip" attribute in same way, but my try failed, maybe because address value was invalid for Xen).

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