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Libvirt provides a portable, long term stable C API for managing the
virtualization technologies provided by many operating systems. It
includes support for QEMU, KVM, Xen, LXC, bhyve, Virtuozzo, VMware
vCenter and ESX, VMware Desktop, Hyper-V, VirtualBox and the POWER
Hypervisor.
7832fac847
So, when building the '-numa' command line, the
qemuBuildMemoryBackendStr() function does quite a lot of checks to
chose the best backend, or to check if one is in fact needed. However,
it returned that backend is needed even for this little fella:
<numatune>
<memory mode="strict" nodeset="0,2"/>
</numatune>
This can be guaranteed via CGroups entirely, there's no need to use
memory-backend-ram to let qemu know where to get memory from. Well, as
long as there's no <memnode/> element, which explicitly requires the
backend. Long story short, we wouldn't have to care, as qemu works
either way. However, the problem is migration (as always). Previously,
libvirt would have started qemu with:
-numa node,memory=X
in this case and restricted memory placement in CGroups. Today, libvirt
creates more complicated command line:
-object memory-backend-ram,id=ram-node0,size=X
-numa node,memdev=ram-node0
Again, one wouldn't find anything wrong with these two approaches.
Both work just fine. Unless you try to migrated from the older libvirt
into the newer one. These two approaches are, unfortunately, not
compatible. My suggestion is, in order to allow users to migrate, lets
use the older approach for as long as the newer one is not needed.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
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| .gnulib@c27f1a356f | ||
| build-aux | ||
| daemon | ||
| docs | ||
| examples | ||
| gnulib | ||
| include | ||
| m4 | ||
| po | ||
| src | ||
| tests | ||
| tools | ||
| .ctags | ||
| .dir-locals.el | ||
| .gitignore | ||
| .gitmodules | ||
| .mailmap | ||
| AUTHORS.in | ||
| autobuild.sh | ||
| autogen.sh | ||
| bootstrap | ||
| bootstrap.conf | ||
| cfg.mk | ||
| ChangeLog-old | ||
| config-post.h | ||
| configure.ac | ||
| COPYING | ||
| COPYING.LESSER | ||
| HACKING | ||
| libvirt-lxc.pc.in | ||
| libvirt-qemu.pc.in | ||
| libvirt.pc.in | ||
| libvirt.spec.in | ||
| Makefile.am | ||
| Makefile.nonreentrant | ||
| mingw-libvirt.spec.in | ||
| README | ||
| README-hacking | ||
| run.in | ||
| TODO | ||
LibVirt : simple API for virtualization
Libvirt is a C toolkit to interact with the virtualization capabilities
of recent versions of Linux (and other OSes). It is free software
available under the GNU Lesser General Public License. Virtualization of
the Linux Operating System means the ability to run multiple instances of
Operating Systems concurrently on a single hardware system where the basic
resources are driven by a Linux instance. The library aim at providing
long term stable C API initially for the Xen paravirtualization but
should be able to integrate other virtualization mechanisms if needed.
Daniel Veillard <veillard@redhat.com>