[libvirt] virDomainGetMaxVcpus does not work as expected
Hi.
When calling virDomainGetMaxVcpus
(http://libvirt.org/html/libvirt-libvirt.html#virDomainGetMaxVcpus) on
an inactive domain, I receive this error:
scala> res2.getMaxVcpus()
libvirt: Domain Config error : Requested operation is not valid: domain is not running
org.libvirt.LibvirtException: Requested operation is not valid: domain is not running
at org.libvirt.ErrorHandler.processError(ErrorHandler.java:31)
at org.libvirt.ErrorHandler.processError(ErrorHandler.java:46)
at org.libvirt.Domain.getMaxVcpus(Domain.java:571)
at .<init>(<console>:13)
...
(this is from Java, but that doesn't matter)
The docs say:
If the guest is inactive, this is basically the same as
virConnectGetMaxVcpus(). If the guest is running this will reflect
the maximum number of virtual CPUs the guest was booted with.
But, apparently, all the driver implementations for
virDomainGetMaxVcpus forward to
<driver>DomainGetVcpusFlags(.., VIR_DOMAIN_AFFECT_LIVE | VIR_DOMAIN_VCPU_MAXIMUM).
_______________________________,~~~~~~~~~~~~~~~~~~~~~~
$ git grep --show-function 'GetVcpusFlags.*AFFECT_LIVE'
src/esx/esx_driver.c=esxDomainGetMaxVcpus(virDomainPtr domain)
src/esx/esx_driver.c: return esxDomainGetVcpusFlags(domain, (VIR_DOMAIN_AFFECT_LIVE |
src/openvz/openvz_driver.c=static int openvzDomainGetMaxVcpus(virDomainPtr dom)
src/openvz/openvz_driver.c: return openvzDomainGetVcpusFlags(dom,
(VIR_DOMAIN_AFFECT_LIVE |
src/qemu/qemu_driver.c=qemuDomainGetMaxVcpus(virDomainPtr dom)
src/qemu/qemu_driver.c: return qemuDomainGetVcpusFlags(dom, (VIR_DOMAIN_AFFECT_LIVE |
src/test/test_driver.c=testDomainGetMaxVcpus(virDomainPtr domain)
src/test/test_driver.c: return testDomainGetVcpusFlags(domain, (VIR_DOMAIN_AFFECT_LIVE
|
src/vbox/vbox_tmpl.c=vboxDomainGetMaxVcpus(virDomainPtr dom)
src/vbox/vbox_tmpl.c: return vboxDomainGetVcpusFlags(dom, (VIR_DOMAIN_AFFECT_LIVE |
AFAICS, this was introduced with
commit 50c51f13e2af04afac46e181c4ed62581545a488
Author: Eric Blake <eblake(a)redhat.com>
Date: Mon Sep 27 16:37:53 2010 -0600
vcpu: make old API trivially wrap to new API
Whereas the function's contract was documented earlier by
commit b412cfadb502c76df095c2c4548c27abf7c4873f
Author: Daniel Veillard <veillard(a)redhat.com>
Date: Thu Mar 8 08:31:07 2007 +0000
To be honest, I'm not sure whether this worked as described at some
time in the past _at all_.
How to fix this? Change the documentation or the flag?
Claudio