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[Libvir] Remote daemon & virDomainFree interaction
by Daniel P. Berrange 24 Jul '07

24 Jul '07

In looking at a problem with domain object cleanup in virt-manager I came across a problem in the remote driver, well the internal driver API itself actually. Specifically the implmenetation of virDomainFree() never calls into the driver API - it simply uses virFreeDomain() release the memory associated with the virDomainPtr object. Couple this with the remote driver though, and virDomainPtr objects in the remote daemon never get released, because the virDomainFree call is never propagated over the wire to the server. Its quite easy to see this in practice. Simply add a printf to the impl of virDomainLookupByName which prints out the ref count. Then run either virsh or virt-manager for a while Get info QEMUGuest1 69 c7a5fdbd-edaf-9455-926a-d65c16db1809 Get info QEMUGuest1 70 c7a5fdbd-edaf-9455-926a-d65c16db1809 Get info QEMUGuest1 71 c7a5fdbd-edaf-9455-926a-d65c16db1809 We need to make virDomainFree call into the driver API, and also make sure that the remote driver implements it. 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] [PATCH] virDomainMigrate version 4 (for discussion only!)
by Richard W.M. Jones 24 Jul '07

24 Jul '07

This is version 4 of the virDomainMigrate patch. It includes remote support, but no qemu, virsh or python yet. And it needs lots more testing which I intend to do more of tomorrow. Interface --------- The interface is now this: virDomainPtr virDomainMigrate (virDomainPtr domain, virConnectPtr dconn, unsigned long flags, const char *dname, const char *uri, unsigned long resource); The caller may set dname, uri and resource to 0/NULL and forget about them. Or else the caller may set, in particular, uri to allow for more complicated migration strategies (especially for qemu). https://www.redhat.com/archives/libvir-list/2007-July/msg00249.html Driver support -------------- As outlined in the diagram in this email: https://www.redhat.com/archives/libvir-list/2007-July/msg00264.html migration happens in two stages. Firstly we send a "prepare" message to the destination host. The destination host may reply with a cookie. It may also suggest a URI (in the current Xen implementation it just returns gethostname). Secondly we send a "perform" message to the source host. Correspondingly, there are two new driver API functions: typedef int (*virDrvDomainMigratePrepare) (virConnectPtr dconn, char **cookie, int *cookielen, const char *uri_in, char **uri_out, unsigned long flags, const char *dname, unsigned long resource); typedef int (*virDrvDomainMigratePerform) (virDomainPtr domain, const char *cookie, int cookielen, const char *uri, unsigned long flags, const char *dname, unsigned long resource); Remote support -------------- To make this work in the remote case I have had to export two private functions from the API which only remote should call: __virDomainMigratePrepare __virDomainMigratePerform The reason for this is that libvirtd is just linked to the regular libvirt.so, so can only make calls into libvirt through exported symbols in the dynamic symbol table. There are two corresponding wire messages (REMOTE_PROC_DOMAIN_MIGRATE_PREPARE and REMOTE_PROC_DOMAIN_MIGRATE_PERFORM) but they just do dumb argument shuffling, albeit rather complicated because of the number of arguments passed in and out. The complete list of messages which go across the wire during a migration is: client -- prepare --> destination host client <-- prepare reply -- destination host client -- perform --> source host client <-- perform reply -- source host client -- lookupbyname --> destination host client <-- lookupbyname reply -- destination host Xen URIs -------- Xen recognises the following forms of URI: hostname hostname:port tcp://hostname/ tcp://hostname:port/ Capabilities ------------ I have extended capabilities with <migration_features>. For Xen this is: <capabilities> <host> <migration_features> <live/> <uri_transports> <uri_transport>tcp</uri_transport> </uri_transports> </migration_features> Rich. -- Emerging Technologies, Red Hat - http://et.redhat.com/~rjones/ Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SL4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 03798903

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[Libvir] OpenVZ XML format and VPS properties get/set interface [long]
by Shuveb Hussain 24 Jul '07

24 Jul '07

Hi, I started a discussion on OpenVZ XML format a while ago. But let me do it again with more explanation about OpenVZ this time, so that others can understand how it is different and how this can best fit into the libvirt model of doing things. Terminology: Virtual Private Server (VPS), Virtual Environment (VE) and Domain are all the same. OpenVZ is a lot about providing QoS to its users. About 20 carefully chosen parameters regarding various resources such as memory, CPU, disk and network are chosen. These are then used to provide minimum guarantee on any system running OpenVZ. Most of the time, these are limits that can be set per Virtual Private Server(VPS). In Xen or QEMU, if a disk image is available(Xen needs an additional kernel), it is possible to run the domain. Then forget all about it after the domain is shutoff. This is not possible in OpenVZ. When a new VPS/VE/Domain needs to be created, it needs a file system. This needs to be created along with its related configuration files in specific locations. Only after this can it be started. There is a "destroy" command available in OpenVZ, which is different from the destroy in libvirt. This will completely erase the file system and remove the related config file as well. Since there are many configurable parameters, the OpenVZ tools provides 2 sample templates or profiles on which newly created Virtual Environments(VEs) can be based. So, during VPS creation, rather than taking a million parameters, the name of the profile is taken as an argument and the variables in the file are used to create the VE. These values can later on be overridden and also be optionally stored in the VE's private config file to ensure persistence across reboots. Since there are many parameters needed during VE creation, using the profile name is practical. So, in the proposed XML file, I'm using the profile name. OpenVZ has its own config file format. We are storing the UUID there in a comment, since UUIDs are not used by OpenVZ. While a VE is created, the easiest way to do it is using a so called template cache. This is just a tar file of a Linux distro FS that is used to create a new file system for a VE. There are no disk images. The VE root fs resides on the host file system as a bunch of files and directories. A few template caches are usually available, say one based on Debian, one based on Fedora Core and another based on Suse. The user can choose which one to use while creating a new VE. However, the name of the template cache is not stored anywhere once the VE filesystem is created. I think one more comment is needed in the per-VE config file for this, just as we are storing the UUID. Here is a sample template. This one is called vps.basic, comes with the OpenVZ tools: ----------------------------------------------------------------- ONBOOT="no" # UBC parameters (in form of barrier:limit) # Primary parameters AVNUMPROC="40:40" NUMPROC="65:65" NUMTCPSOCK="80:80" NUMOTHERSOCK="80:80" VMGUARPAGES="6144:2147483647" # Secondary parameters KMEMSIZE="2752512:2936012" TCPSNDBUF="319488:524288" TCPRCVBUF="319488:524288" OTHERSOCKBUF="132096:336896" DGRAMRCVBUF="132096:132096" OOMGUARPAGES="6144:2147483647" # Auxiliary parameters LOCKEDPAGES="32:32" SHMPAGES="8192:8192" PRIVVMPAGES="49152:53575" NUMFILE="2048:2048" NUMFLOCK="100:110" NUMPTY="16:16" NUMSIGINFO="256:256" DCACHESIZE="1048576:1097728" PHYSPAGES="0:2147483647" NUMIPTENT="128:128" # Disk quota parameters (in form of softlimit:hardlimit) DISKSPACE="1048576:1153434" DISKINODES="200000:220000" QUOTATIME="0" # CPU fair sheduler parameter CPUUNITS="1000" ------------------------------------------------------------ Here is the proposed XML format: <domain type='openvz'> <name>105</name> <uuid>8509a1d4-1569-4467-8b37-4e433a1ac7b1</uuid> <filesystem> <template>gentoo-20060317-i686-stage3</template> <quota level='first'>10737418240</quota> <quota level='second' uid='500'>5368709120</quota> </filesystem> <profile>vps.basic</profile> <devices> <interface> <ipaddress>192.168.1.105</ipaddress> </interface> </devices> <nameserver>192.168.1.1</nameserver> <hostname>fedora105</hostname> </domain> I don't think the "filesystem" tag can fit logically into "devices", since it has quota and other information. The "template" is the name of the template cache used to create the VE. One of the main reasons many people(especially hosting providers) use OpenVZ is since it can be used to provide service level agreements. There must be a way to set/get various VPS parameters from libvirt. I understand concerns about driver specific code in libvirt based clients like virt-manager. The capabilities paradigm will not fit here, since this is simply about various properties of the VE/domain, not the hardware or the VM capabilities. Please correct me, if I am wrong. So, how to we do it? Thanks and Regards, -- Shuveb Hussain Unix is very user friendly. It is just a little choosy about who its friends are http://www.binarykarma.com

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[Libvir] [PATCH] virDomainMigrate (version 5) (for discussion only, but getting there)
by Richard W.M. Jones 23 Jul '07

23 Jul '07

This is a rolled up patch for virDomainMigrate, including virsh and Python fixes. Changes since last time: - VIR_MIGRATE_LIVE is exported to Python - 'resource' parameter is now named 'bandwidth' - there is now an extra domainMigrateFinish step It needs a bit more testing which I can't do today while I'm at the office. Rich.

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[Libvir] [PATCH] Document VIRSH_DEFAULT_CONNECT_URI
by David Lutterkort 23 Jul '07

23 Jul '07

I keep forgetting the exact name of VIRSH_DEFAULT_CONNECT_URI - patch to add it to the man page attached. David

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[Libvir] FW: [et-mgmt-tools] Release 0.200.0 of virtinst
by Daniel P. Berrange 20 Jul '07

20 Jul '07

FYI a new libvirt based tool for cloning VMs... ----- Forwarded message from "Daniel P. Berrange" <berrange(a)redhat.com> ----- > Date: Thu, 19 Jul 2007 03:16:56 +0100 > From: "Daniel P. Berrange" <berrange(a)redhat.com> > To: et-mgmt-tools(a)redhat.com > Subject: [et-mgmt-tools] Release 0.200.0 of virtinst > > I'm happy to announce the release of virtinst version 0.200.0 > > This release introduces the virt-clone tool which provides the ability > to clone an existing inactive guest. The disk images will be copied, > new MAC address, UUID and name will be given to the guest. Documentation > is improved with the addition of manual pages for both virt-install and > virt-clone. Validation of input parameters has been further enhanced, > and re-factored to allow sharing with virt-manager. The virt-install > tool can be used to boot live CD images, with or without underlying > storage. > > It is available for download from the usual place: > > http://virt-manager.org/download.html > > Or directly: > > http://virt-manager.org/download/sources/virtinst/virtinst-0.200.0.tar.gz > > Thanks to everyone who has participated in development & testing of the > code in this new release! > > Regards, > Dan. ----- End forwarded message ----- 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] [PATCH]0/3 OpenVZ driver : Some clean ups
by Shuveb Hussain 19 Jul '07

19 Jul '07

Hi, Here are some cleanups as per discussions on the list: Change log: * Make sure we are running on OpenVZ enebled kernel in the driver open() method * Some minor macro cleanups * Use generic UUID parsing rather than own and scanf() * Made private functions static * New files utils.[c,h] added that have 2 functions virExec and virExecNonBlock * Removed popen and used virExec in openvz_driver.c * qemu_driver.c updated to use new virExecNonBlock() functions instead of qemudExec, which is removed Thanks, -- Shuveb Hussain Unix is very user friendly. It is just a little choosy about who its friends are http://www.binarykarma.com

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[Libvir] Xen reboot does not work with Sys::Virt perl binding
by Keck, Christian (ext) 19 Jul '07

19 Jul '07

Hello guys! I am using the perl bindings (Sys::Virt) to manage my virtual xen hosts. Because it directly maps the C api, I thought it's a good idea to ask you instead of the author of this module. Xen version is 3.0 with libvirt 0.1.9 on a red hat box. while calling the reboot method i get following error: libvirt error code: 0, message: Unknown problem In this case the virtual system does not reboot. But with shutdown method, which throw the same error, the system shuts down correctly. Here is my code: my $vmm = Sys::Virt->new(); my $dom = eval { $vmm->get_domain_by_name( $p->{ name } ) }; $dom->reboot(&Sys::Virt::Domain::REBOOT_RESTART); Is this a known issue? Thank you for your help. Best regards, Christian

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[Libvir] RFC: format for mapping host devices to guest
by Daniel P. Berrange 19 Jul '07

19 Jul '07

I'm considering the problem of mapping host USB devices through to the guest as one of the 2 remaining bits of USB support needed (the other being the mapping disks through as USB mass storage). I have previously mentioned some ideas in this mail, though looking back on this I don't much like them https://www.redhat.com/archives/libvir-list/2007-March/msg00205.html Also, there was just the message about a desire to support mapping of PCI devices. The USB stuff I want todo with both Xen and QEMU. In Xen, USB device passthrough is based on: usbdevice=host:[bus id].[device id] eg usbdevice=host:003.001 Or usbdevice=host:[vendor id]:[product id] eg usbdevice=host:0483:2016 In QEMU, USB device passthrough is pretty much the same with command line args: -usbdevice host:[bus id].[device id] eg -usbdevice host:003.001 Or -usbdevice host:[vendor id]:[product id] eg -usbdevice host:0483:2016 Finally, in Xen, PCI device passthrough is done with pci=['pci device id',....] eg pci=['00:1f.3'] So we need some form of element under the <devices> section per device to map through. At minimum this will need the source device info. If we are to support unplugging of USB devices in QEMU it is neccessary to have the target device id - this is generated by QEMU when attaching the USB device. So to attach a device: <host bus='usb'> <source device="003.001"/> </host> Or <host bus='usb'> <source vendor='0483' product='2016'> </host> The first form is useful for live hotplug - where you know the exact device instance. The second form is useful for permanent config - you don't know what device id it'll have since it may be plugged into the host in any order. When splitting the XML back out, QEMU would fill in the target info giving us either: <host bus='usb'> <source dev='003.001'/> <target dev='001.005'/> </host> Or <host bus='usb'> <source vendor='0483' product='2016'/> <target dev='001.005'/> </host> This is suitable for giving to virDomainDetachDevice() - we use the target dev for the QEMU monitor 'usb-detach' command. Now PCI would be similar - no hotplug to worry about here though, and no need (or availability) or target info. So the XML would simply be <host bus='pci'> <source dev='00:1f.3'/> </host> NB I choose 'host' as the element name since we're basically giving the guest an arbitrary host device. My previous email had thought about calling it 'bus' but we're not really defining a bus in this context and there may very well be some scenario in the future where we do need to represent the concept of a 'bus' in the XML directly. 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] [PATCH]3/3 OpenVZ driver : qemu_driver.c changes
by Shuveb Hussain 19 Jul '07

19 Jul '07

-- Shuveb Hussain Unix is very user friendly. It is just a little choosy about who its friends are http://www.binarykarma.com

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