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[Libvir] Semantics for ListDomains/ ListDefinedDomains
by Daniel P. Berrange 03 Sep '06

03 Sep '06

So I was thinking a little about lifecycle support for passive domains in libvirt and wanted to clarify the intended semantics of the two methods: virConnectListDomains virConnectListDefinedDomains Am I correct in thinking that virConnectListDefinedDomains will list a domain if-and-only-if its state == 'shutoff', and that virConnectListDomains will list a domain if-and-only-if its state != 'shutoff' ie, when I start a defined domain with 'virDomainCreate', it will be removed from the 'ListDefinedDomains' set and added to the 'ListDomains' set. Likewise when shutting down it'll move back the other way. Or will the virConnectListDefinedDomains call always list a domain with a config file, even if it is running ? I realize this is a little hypothetical since XenD doesn't have lifecycle management yet, but it matters to the test backend, and any potential QEMU / UML backend, and the future XenD XML-RPC backend 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] Libvirt / Xen incompatible versions.
by Michel Gauthier 01 Sep '06

01 Sep '06

We've just installed the last advanced version of Xen on our IA64 platform. Unfortunatly, the build of the 0.1.4 version of libvirt with this version of Xen is not successful. The C header file of Xen /usr/include/xen/dom0_ops.h used by libvirt in xen_internal.c has been modified. The dom0_getdomaininfo_t structure is no more decared in this header file. Are you aware of this problem? What is the latest version of Xen on which libvirt has been successfully built and tested? Thanks.

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[Libvir] [QEMU 3/3] the qemu driver & daemon
by Daniel P. Berrange 31 Aug '06

31 Aug '06

Attached is the patch for the qemu driver & daemon process Since there is no scalable way to determine active standalone QEMU instances, or access their monitor connection, the backend implements a management daemon - called 'qemud' - which takes care of managing the complete lifecycle of QEMU virtual machines. The libvirt driver is a thin shim which talks to qemud via a UNIX domain socket - the wire protocol is modelled after the protocol used for libvirt_proxy, but obviously contains alot more functions since its full read/write, not just read-only. There is intended to be one qemud instance per UNIX user - the so called 'session' instance, and optionally one system global instance runing as root (or a system daemon account?) - the so called 'system' instance. When using libvirt, the URIs for each are 'qemu:///session' and 'qemu:///system' respectively. The UNIX socket for session instances is $HOME/.qemud and is chmod 0700 - no support is provided for users connecting to each other's instances. Although we could trivially extend to create a read-only socket $HOME/.qemud-ro if desired. The system instance is currently not finished but intended to run in /var/run/qemud or some such. The backend code is in src/qemu_internal.h, src/qemu_internal.c, the daemon code is in qemud/* with qemud/protocol.h defining the network wire protocol. This latter header file is also included by src/qemu_internal.c - qemud.c - the main daemon management code - handles all network I/O and forking / cleanup of QEMU processes. The implementation is poll() based & completely non-blocking. All requests/replies from a single client are, however, serialized. - dispatch.c - takes care of serializing/de-serializing requests/replies from/to libvirt - called from qemud.c when a complete message is available. - driver.c - the implementation of each request from libvirt - called from dispatch.c - config.c - manages reading & writing of XML files for inactive domains in the $HOME/.qemud.d/*.xml. Also takes care of generating a suitable command line for execing qemu. In terms of hardware, there is support for - harddisk - floppy, cdrom, harddisk - graphics - VNC - memory - virtual CPUs In particular no support for - networking - sound - non-native CPU types - boot order But its enough to demonstrate the practice. 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] Added gettext translation support
by Daniel P. Berrange 31 Aug '06

31 Aug '06

The attached patch adds support for translating all text strings in libvirt and virsh using gettext. It also fixes up many error messages, and updates others to use a consistent style - so we don't have lots of slightly differenet translations of the same thing. It also adds an 'autoclean.sh' which deletes all autotools generated junk so you can more easily generate useful patches using diff against a pristine source tree. The patch adds a placeholder en_GB.po file (with no changes). It is expected that real translations for a large number of languages will be completed over course of next couple of months 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] [QEMU 2/3] add commands for inactive domains to virsh
by Daniel P. Berrange 30 Aug '06

30 Aug '06

The attached patch adds new commands to virsh, and modifies the list command. * 'list' is given two additional parameters '--inactive' to tell it to list inactive instances, instead of active instances, and --all to tell it to list both active & instance domains. NB inactive domains will show with an ID of -1 and state 'shut off'. * 'define' defines an inactive domain - instructing the backend to save the XML definition in some persist location. The domain is not started. * 'undefine' removes an inactive domain - the persist config file managed by the backend is deleted. The domain must not be running when this is run. * 'start' starts up an inactive domain which was previously defined via the 'define' command. 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] [QEMU 1/3] hook up driver methods for inactive domains
by Daniel P. Berrange 30 Aug '06

30 Aug '06

The attached patch prepares the driver method API to support inactive domains. The following methods are hooked up: * virConnectListDefinedDomains * virConnectNumOfDefinedDomains * virDomainDefineXML * virDomainUndefine * virDomainCreate It sets all existing drivers to have NULL in these fields. The existing code in virDomainDefineXML was ripped out since it was found to be more trouble than it was worth - the backend driver needed to repeat most of the logic anyway - so better just to delegate the whole lot. 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] generator.py -- why?
by pvetere＠redhat.com 29 Aug '06

29 Aug '06

Hi all. So, I found a bug in the python bindings that I'd really like to fix, but when I sat down to do so I quickly found myself mired in a swampy mess of code generation: generator.py. :-) Now, I feel compelled to ask -- why don't we just have a static libvirt.py file that is WYSIWYG? The generator.py program alone is longer than the file it generates, and having a static file would not only make the code easier to read, but would also make bug fixing much simpler. But, I'm sure there's got to be a good reason for it. :-) Here's a program that produces the bug I tried to address: import libvirt def get_domain(dom_name): conn = libvirt.openReadOnly(None) domain = conn.lookupByName(dom_name) return domain d = get_domain("mydomain") print d.info() This is a fairly typical "factory" pattern I could imagine people using. The problem is that the connection object falls out of scope after the get_domain routine ends, and is therefore garbage collected. This leaves the "d" domain object with no valid connection, resulting in a "libvir: Xen error : failed Xen syscall ioctl 3166208" error. The simple solution would be for the connection object to pass a reference to itself into each domain object it creates. The domain objects would then maintain the reference until they are destroyed. I valiantly tried to follow the table-based patterns used in generator.py to fix this problem, but I found myself inventing somewhat arbitrary rules just to force the code I wanted it to output. And hence, $SUBJECT. :-) Pete

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[Libvir] [QEMU 0/3] QEMU support for libvirt
by Daniel P. Berrange 28 Aug '06

28 Aug '06

The following series of patches add support for QEMU to libvirt. The patches are: - libvirt-drivers-qemu.patch - hook up methods for inactive domains - libvirt-virsh-qemu.patch - hook up inactive domain methods to virsh - libvirt-backend-qemu.patch - the main QEMU backend The patches will be explained further in each email which follows. NB, the first two patches are ready for inclusion, but the last one needs more error handling, and another audit of the networking code to check in particular buffer sizes. For testing I used Damn Small Linux, and QEMU 0.8.1 from Fedora Core 5 (the one with VNC support) wget http://distro.ibiblio.org/pub/linux/distributions/damnsmall/current/dsl-3.0… Here is a suitable config file: <domain type='qemu'> <name>dsl</name> <uuid>fff64701-45b9-11cb-88e3-afbfe5370493</uuid> <memory>131072</memory> <vcpu>20</vcpu> <devices> <disk type='file' device='cdrom'> <source file='/home/berrange/dsl-3.0.1.iso'/> <target dev='hdc'/> </disk> <graphics type='vnc' port='5906'/> </devices> </domain> An example session with virsh: [berrange@aubergine ~]$ export VIRSH_DEFAULT_CONNECT_URI=qemu:///session [berrange@aubergine ~]$ virsh list Id Name State ---------------------------------- [berrange@aubergine ~]$ virsh define $HOME/dsl.xml Domain dsl defined from /home/berrange/dsl.xml [berrange@aubergine ~]$ virsh list --all Id Name State ---------------------------------- -1 dsl shut off [berrange@aubergine ~]$ virsh dominfo dsl Id: -1 Name: dsl UUID: fff64701-45b9-11cb-88e3-afbfe5370493 OS Type: linux State: shut off CPU(s): 20 Max memory: 131072 kB Used memory: 131072 kB [berrange@aubergine ~]$ virsh start dsl Domain dsl started [berrange@aubergine ~]$ virsh list --all Id Name State ---------------------------------- 1 dsl running [berrange@aubergine ~]$ virsh dumpxml dsl <domain type='qemu' id='1'> <name>dsl</name> <uuid>fff64701-45b9-11cb-88e3-afbfe5370493</uuid> <memory>131072</memory> <vcpu>20</vcpu> <devices> <disk type='file' device='cdrom'> <source file='/home/berrange/dsl-3.0.1.iso'/> <target dev='hdc'/> <readonly/> </disk> <graphics type='vnc' port='5906'/> </devices> </domain> [berrange@aubergine ~]$ virsh destroy dsl Domain dsl destroyed [berrange@aubergine ~]$ virsh list --all Id Name State ---------------------------------- -1 dsl shut off I'm also happy to report that it is also possible to use virt-manager with the QEMU support - just enter qemu:///session as the URI. That said you can't use the VM creation wizard, but it should be easy to hook that up. The fact that virt-manager works without modification is a really great proof of the value of libvirt abstract driver backend API concept - validating the decision not to make a Xen specific API. 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] Support graphical console for PV Xen guests
by Jeremy Katz 26 Aug '06

26 Aug '06

With the paravirt framebuffer patches for Xen, we can support having a graphical console for PV as well as HVM guests. The attached adds support to libvirt by breaking out the <graphics> parsing into its own function that can be used by both PV and HVM guests. It also adds support for looking at the appropriate sexpr for the vnc/sdl console for PV guests. One thing that is potentially not okay is that I've changed sexpr_node to take a format string instead of just a const char *, but since it's not public API and doesn't actually change anything for callers I think it should be fine. If not, let me know and I can change it. Jeremy

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[Libvir] RFC: A more convenient 'virsh create' command
by Daniel P. Berrange 26 Aug '06

26 Aug '06

The current implementation of 'virsh create' takes an XML file as its only parameter & creates a domain from this. This is great if you have a suitable XML file already, but if you are just trying to automate some simple tasks from the shell then the need to use XML is a little cumbersome. Thus I was thinking perhaps we could have an alternate way to define a new VM (keep the current XML based way too of course) QEMU for example makes it very easy to launch a new VM: qemu -m 256 -hda /path/to/image.dsk -hdc /path/to/boot.iso Taking inspiration from this syntax we could allow: virsh start -m 256 -hda /path/to/image.dsk -hdc /path/to/boot.iso -name Foo Internally, the 'start' command would simply transform these command line args into the neccessary libvirt XML and then call the normal create functions. Another way would be have a 'genxml' command, which accepted these list of devices / config properties & then printed out appropriate XMl. This could be piped to the regular 'virsh create' command virsh genxml -m 256 -hda /path/to/image.dsk -hdc /path/to/boot.iso \ -name Foo | virsh create - This isn't so critical for Xen, because people are already used to writing config files before creating the domain, but when we get a QEMU backend i think such a convenient method for defining new VMs will be neccessary to encourage users to use virsh instead of manually calling 'qemu'. Even for Xen users it would make shell script easier though :-) 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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