November 2012 - Devel - libvirt List Archives

Re: [libvirt] [PATCH 1/2] Introduce a lock for libxl long-running api
by Jim Fehlig 07 Nov '12

07 Nov '12

Bamvor Jian Zhang wrote: >>> +static int >>> +libxlDomainAbortJob(virDomainPtr dom) >>> +{ >>> + libxlDriverPrivatePtr driver = dom->conn->privateData; >>> + virDomainObjPtr vm; >>> + int ret = -1; >>> + libxlDomainObjPrivatePtr priv; >>> + >>> + libxlDriverLock(driver); >>> + vm = virDomainFindByUUID(&driver->domains, dom->uuid); >>> + libxlDriverUnlock(driver); >>> + if (!vm) { >>> + char uuidstr[VIR_UUID_STRING_BUFLEN]; >>> + virUUIDFormat(dom->uuid, uuidstr); >>> + virReportError(VIR_ERR_NO_DOMAIN, >>> + _("no domain with matching uuid '%s'"), uuidstr); >>> + goto cleanup; >>> + } >>> + >>> + if (libxlDomainObjBeginJob(driver, vm, LIBXL_JOB_ABORT) < 0) >>> + goto cleanup; >>> + >>> + if (!virDomainObjIsActive(vm)) { >>> + virReportError(VIR_ERR_OPERATION_INVALID, >>> + "%s", _("domain is not running")); >>> + goto endjob; >>> + } >>> + >>> + priv = vm->privateData; >>> + >>> + if (!priv->job.asyncJob) { >>> + virReportError(VIR_ERR_OPERATION_INVALID, >>> + "%s", _("no job is active on the domain")); >>> + goto endjob; >>> + } else { >>> + virReportError(VIR_ERR_OPERATION_INVALID, >>> + _("cannot abort %s; use virDomainDestroy instead"), >>> + libxlDomainAsyncJobTypeToString(priv->job.asyncJob)); >>> + goto endjob; >>> + } >>> >>> >> >> This function will always fail with the above logic. ret is initialized >> to -1 and is never changed. >> >> Is it even possible to safely abort a libxl operation? If not, this >> function should probably remain unimplemented. Maybe it will be useful >> when the libxl driver supports migration. >> > return error because of the there is no cancelation opeartion in libvirt libxl > driver with xen 4.1. according to xen4.2 release document, maybe the > cancelation of long-running jobs is supported. I finally got some time to take a closer look at Xen 4.2 libxl and notice that the "long running" operations (create, save, dump, restore, etc.) now support a 'libxl_asyncop_how *ao_how' parameter to control their concurrency. If ao_how->callback is NULL, a libxl_event is generated when the operation completes. We'll just need to handle these events in the existing libxlEventHandler. Some of the async operations support reporting intermediate progress (e.g. for libxlDomainGetJobInfo), but at this time none of them support cancellation AFAICT. With the new asynchronous support in Xen 4.2 libxl, IMO we should delay this patchset until converting the driver to support 4.2. I didn't think this patch would be affected by Xen 4.1 vs 4.2 libxl, but it is and I don't see any reason to add code that further complicates the conversion. BTW, Ondrej was working on a patch to convert the driver to 4.2. Now that I have some free time, I'll pick up some of this work too. > but it is still useful for save, dump and migration(in future), because libvirt > should block the user abort operation othervise xenlight might crash > If it is left unimplemented, libvirt would block the operation anyhow, failing with "not supported" Regards, Jim

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[libvirt] Add hyperthreaded sibling info to virsh capabilities
by Dusty Mabe 07 Nov '12

07 Nov '12

Hi, Would it be possible to augment the output produced in virsh capabilities to also provide the hyperthreaded sibling of a processor? For example the information would look something like: <topology> <cells num='2'> <cell id='0'> <cpus num='8'> <cpu id='1' sibling='9'/> <cpu id='3' sibling='11'/> <cpu id='5' sibling='13'/> <cpu id='7' sibling='15'/> <cpu id='9' sibling='`1'/> <cpu id='11' sibling='3'/> <cpu id='13' sibling='5'/> <cpu id='15' sibling='7'/> </cpus> </cell> <cell id='1'> <cpus num='8'> <cpu id='0' sibling='8'/> <cpu id='2' sibling='10'/> <cpu id='4' sibling='12'/> <cpu id='6' sibling='14'/> <cpu id='8' sibling='0'/> <cpu id='10' sibling='2'/> <cpu id='12' sibling='4'/> <cpu id='14' sibling='6'/> </cpus> </cell> </cells> </topology> I notice that you guys are actually using some of the numactl stuff (numa.h) to query for the cpus on a given node and I have combed through that code to see if it provided any info about hyperthreaded siblings but from what I can tell it does not. I have tinkered around with the hwloc libraries (http://www.open-mpi.org/projects/hwloc/) and have written a short program to print out each logical cpu and its hyperthreaded sibling (see attached) The output from it looks like so: [root@hostname ~]# ./a.out *** PU: 0 Hyperthreaded Sibling: 8 *** PU: 8 Hyperthreaded Sibling: 0 *** PU: 2 Hyperthreaded Sibling: 10 *** PU: 10 Hyperthreaded Sibling: 2 *** PU: 4 Hyperthreaded Sibling: 12 *** PU: 12 Hyperthreaded Sibling: 4 *** PU: 6 Hyperthreaded Sibling: 14 *** PU: 14 Hyperthreaded Sibling: 6 *** PU: 1 Hyperthreaded Sibling: 9 *** PU: 9 Hyperthreaded Sibling: 1 *** PU: 3 Hyperthreaded Sibling: 11 *** PU: 11 Hyperthreaded Sibling: 3 *** PU: 5 Hyperthreaded Sibling: 13 *** PU: 13 Hyperthreaded Sibling: 5 *** PU: 7 Hyperthreaded Sibling: 15 *** PU: 15 Hyperthreaded Sibling: 7 Would you guys ever consider adding something like this? I would be willing to help create a patch if I had some guidance. Thanks for your time, Dusty Mabe

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[libvirt] [PATCH 0/2] make external snapshots easier in virsh
by Eric Blake 07 Nov '12

07 Nov '12

Creating external snapshots with 'virsh snapshot-create' is awkward, as it requires quite a bit of XML. This adds support in the snapshot-create-as command to make the task easier. Eric Blake (2): virsh: make ,, escape parsing common virsh: add snapshot-create-as memspec support tests/virsh-optparse | 5 ++- tools/virsh-snapshot.c | 102 ++++++++++++++++++++++++++++++++++++------------- tools/virsh.c | 53 +++++++++++++++---------- tools/virsh.pod | 17 ++++++--- 4 files changed, 122 insertions(+), 55 deletions(-) -- 1.7.11.7

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[libvirt] [PATCH v2 0/2] Emit more events
by Michal Privoznik 07 Nov '12

07 Nov '12

diff to v1: -a new event invented -more APIs updated Michal Privoznik (2): Introduce new VIR_DOMAIN_EVENT_SUSPENDED_API_ERROR event qemu: Emit event if 'cont' fails examples/domain-events/events-c/event-test.c | 3 + examples/domain-events/events-python/event-test.py | 2 +- include/libvirt/libvirt.h.in | 1 + src/qemu/qemu_driver.c | 59 ++++++++++++++------ 4 files changed, 47 insertions(+), 18 deletions(-) -- 1.7.8.6

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[libvirt] Limit autostarting of domains to a few at a time.
by Ruben Kerkhof 07 Nov '12

07 Nov '12

Hi list, I have about a hundred kvm vm's on a physical host, all marked as autostart. As soon as libvirtd starts up, all vms get started and they start fighting for disk I/O. Would it be possible to add an option to wait a while before starting the next vm? Batch-starting them in parallel, let's say 10 at a time, would be great too. I know I could use the libvirt-guest init script to do this, but we rely on the autostart property for several purposes. Kind regards, Ruben Kerkhof

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[libvirt] Using Generic Ethernet type with custom networking without lowering the host security level
by Ishimoto, Ryu 07 Nov '12

07 Nov '12

Hi Everyone, I wanted to ask a question about the 'generic ethernet' NIC type. If I understand its security concerns correctly, because it expects QEMU to execute scripts to bring up/down the interface, it requires that the host security level is lowered to allow QEMU to perform privileged operations. While this is definitely not desirable, I'm have a situation where I want to use libvirt to work with a custom networking solution that is neither Linux bridge or OpenVSwitch. Currently, to make this happen, I would create a tap interface myself, configure it(like adding it to the datapath), and inform libvirt of this interface as a generic ethernet type with script attribute set to ''. In order to make this work without the security issue mentioned, I would like to suggest a new device type(or just a modification of generic ethernet type) in which libvirt accepts an interface name, opens it and gets its fd, and passes the fd to QEMU. QEMU does not run any scripts and expects the tap interface to be already open. Another solution might be to allow custom scripts to be plugged into libvirt that allows you to add an interface to a bridge instead of running brctl or ovs-vsctl. The latter solution lets libvirt create the tap interface, whereas the former requires that the tap is 'plugged' into the network before libvirt takes control for the VM to have connectivity when it launches. I prefer the former because it seems less disruptive while providing similar features. I would be more than happy to send a patch for this, and I apologize that this lacks details, but I just wanted to first make sure that what I'm suggesting here makes sense and that I'm not missing something critical, as I am fairly new to libvirt. Thanks, Ryu

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[libvirt] Proposed: replace radvd with dnsmasq for Router Advertizing
by Gene Czarcinski 06 Nov '12

06 Nov '12

I have been doing some testing and dnsmasq is capable of handling the service currently provided by radvd. To implement this in dnsmasq requires the following: if an IPv6 dhcp-range is specified, then add: enable-ra if no IPv6 dhcp-range is specified, then add: dhsp-range=<IPv6-subnet>,ra-only Tested. The second one will work with basic dnsmasq-2.6.3. The first one and dhcp-range itself only works with dnsmasq-2.64 (when released) or dnsmasq-2.63+patches. Since dnsmasq-2.48 does not support IPv6 dhcp but does handle IPv6 for dns and CentOS 6 does include radvd, I also propose that a libvirtd.conf option be added. If the option is not present or set off, then radvd is used. If the option is set on, then dnsmasq is used. At some point in the future, it can be decided whether to keep using radvd or not. Comments? Suggestions? Gene

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[libvirt] [PATCH] qemu: Add ability to disable autostarting of guests on daemon start
by Peter Krempa 06 Nov '12

06 Nov '12

When the daemon is starting it autostarts all guests marked as autostartable. This is not an ideal solution for autostarting if there's a lot of domains configured so. After autostarting all right away the guests start competing for disk I/O and the boot is prolonged unnecessarily. This patch adds a config option to disable autostarting to leave it on user scripts that may use mechanisms to reduce load of the host by limiting the number of guests started in parallel. Unfortunately, there's no simple way we could do this in libvirt. The problem is how to detect that the guest has finished booting as it's mostly a black box for libvirt. There area few options: 1) Wait until I/O load of the guest drops. - This is insufficient on guests that do heavy I/O all the time. 2) Let the guest tell us. - Not every OS has the ability to have a guest agent. 3) Wait for certain amount of time. - Very limited amount of control on diverse guests. With this functionality, the user may write his own script that load balances the autostart in a sane way with accordance to his infrastructure (Query agents, check I/O, use configurable timeouts) while stil being able to mark the domains as autostartable with all the benefits (virsh list --all --autostart). --- We could also add an example script based on parts of libvirt-guests to show how to use this. --- src/qemu/qemu.conf | 7 +++++++ src/qemu/qemu_conf.c | 4 ++++ src/qemu/qemu_conf.h | 2 ++ src/qemu/qemu_driver.c | 5 ++++- 4 files changed, 17 insertions(+), 1 deletion(-) diff --git a/src/qemu/qemu.conf b/src/qemu/qemu.conf index dd853c8..91115bf 100644 --- a/src/qemu/qemu.conf +++ b/src/qemu/qemu.conf @@ -2,6 +2,13 @@ # All settings described here are optional - if omitted, sensible # defaults are used. +# When the qemu driver starts all guests that are marked to be +# started automaticaly are started (at once). This option disables +# autostarting of the guests. The user can use a script to do so in +# a more sensible way. Eg. wait for guest to start up, before continuing. +# +#disable_autostart = 1 + # VNC is configured to listen on 127.0.0.1 by default. # To make it listen on all public interfaces, uncomment # this next option. diff --git a/src/qemu/qemu_conf.c b/src/qemu/qemu_conf.c index dc4d680..598b34e 100644 --- a/src/qemu/qemu_conf.c +++ b/src/qemu/qemu_conf.c @@ -153,6 +153,10 @@ int qemudLoadDriverConfig(struct qemud_driver *driver, return -1; \ } + p = virConfGetValue(conf, "disable_autostart"); + CHECK_TYPE("disable_autostart", VIR_CONF_LONG); + if (p && p->l) driver->disableAutoStart = true; + p = virConfGetValue(conf, "vnc_auto_unix_socket"); CHECK_TYPE("vnc_auto_unix_socket", VIR_CONF_LONG); if (p) driver->vncAutoUnixSocket = p->l; diff --git a/src/qemu/qemu_conf.h b/src/qemu/qemu_conf.h index 2c7f70c..fb6e317 100644 --- a/src/qemu/qemu_conf.h +++ b/src/qemu/qemu_conf.h @@ -156,6 +156,8 @@ struct qemud_driver { int keepAliveInterval; unsigned int keepAliveCount; int seccompSandbox; + + bool disableAutoStart; }; typedef struct _qemuDomainCmdlineDef qemuDomainCmdlineDef; diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c index 978af57..3b4928f 100644 --- a/src/qemu/qemu_driver.c +++ b/src/qemu/qemu_driver.c @@ -888,7 +888,10 @@ qemudStartup(int privileged) { qemuDriverUnlock(qemu_driver); - qemuAutostartDomains(qemu_driver); + if (!qemu_driver->disableAutoStart) + qemuAutostartDomains(qemu_driver); + else + VIR_WARN("QEMU domain autostarting is disabled"); if (conn) virConnectClose(conn); -- 1.8.0

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[libvirt] [PATCH] qemu: Emit event if save fails
by Michal Privoznik 06 Nov '12

06 Nov '12

When we are doing a (managed-) save of a domain, we stop its processors firstly. And if the process of saving fails for some reason we try to wake them up again. However, if this fails, an event should be emitted so mgmt application can decide what to do. --- I am not completely sure about combination of event and event detail, maybe we need to invent a new combination. Suggestions? VIR_DOMAIN_EVENT_STOPPED_FAILED means an hypervisor error which may fit when 'cont' fails. src/qemu/qemu_driver.c | 6 +++++- 1 files changed, 5 insertions(+), 1 deletions(-) diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c index 978af57..e1c6067 100644 --- a/src/qemu/qemu_driver.c +++ b/src/qemu/qemu_driver.c @@ -2990,8 +2990,12 @@ endjob: rc = qemuProcessStartCPUs(driver, vm, dom->conn, VIR_DOMAIN_RUNNING_SAVE_CANCELED, QEMU_ASYNC_JOB_SAVE); - if (rc < 0) + if (rc < 0) { VIR_WARN("Unable to resume guest CPUs after save failure"); + event = virDomainEventNewFromObj(vm, + VIR_DOMAIN_EVENT_STOPPED, + VIR_DOMAIN_EVENT_STOPPED_FAILED); + } } } if (qemuDomainObjEndAsyncJob(driver, vm) == 0) -- 1.7.8.6

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[libvirt] [PATCH v2 0/2] Sanitize whitespace around brackets
by Daniel P. Berrange 06 Nov '12

06 Nov '12

This is a followup to: https://www.redhat.com/archives/libvir-list/2012-October/msg00878.html In this iteration we check for several more whitespace violations than before, and also document the rules in the hacking file To be applied immediately after 1.0.0 release.

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