[libvirt] RFC: APIs for managing resource groups

Historically for the QEMU/LXC drivers we've simply put each virtual instance in a dedicated cgroup, under the path $LIBVIRT_CGROUP_LOCATION | +- libvirt | +- qemu | | | +- vm1 | +- vm2 | +- vm3 | +- lxc | +- cont1 +- cont2 +- cont3 for a variety of reasons this nesting sucks. It is too deep causing kernel performance problems, its structure does not easily allow for calculating fixed % shares, it does not allow for grouping of VMs. We need to simplify our layout and also introduce some APIs for the grouping of VMs. I won't go into specifics of a new cgroups layout here, just focus on the question of defining a set of APIs that are generic to any hypervisor, for the purpose of setting up VM resource groups. I'm calling the resource cgroup a "partition", since this is all about partitioning workloads. I anticipate a new top level object and APIs for creating/defining it in the usual manner: typedef struct _virPartition virPartition; typedef virPartition *virPartitionPtr; int virConnectListAllPartitions(virConnectPtr conn, virPartitionPtr **partitions, unsigned int flags); virPartitionPtr virPartitionDefineXML(virConnectPtr conn, const char *xml, unsigned int flags); int virPartitionCreate(virPartitionPtr partition, unsigned int flags); int virPartitionCreateXML(virPartitionPtr partition, const char *xml, unsigned int flags); int virPartitionDestroy(virPartitionPtr partition, unsigned int flags); int virPartitionUndefine(virPartitionPtr partition, unsigned int flags); Then I think we'll duplicate all the APIs for setting resource tunables from virDomainPtr against the new object, so we get int virPartitionGetSchedulerParameters(virPartitionPtr partition, virTypedParameterPtr params, int *nparams, unsigned int flags); int virPartitionSetSchedulerParameters(virPartitionPtr partition, virTypedParameterPtr params, int nparams, unsigned int flags) int virDomainSetBlkioParameters(virDomainPtr domain, virTypedParameterPtr params, int nparams, unsigned int flags); int virDomainGetBlkioParameters(virDomainPtr domain, virTypedParameterPtr params, int *nparams, unsigned int flags); int virDomainSetMemoryParameters(virDomainPtr domain, virTypedParameterPtr params, int nparams, unsigned int flags); int virDomainGetMemoryParameters(virDomainPtr domain, virTypedParameterPtr params, int *nparams, unsigned int flags); int virDomainSetNumaParameters(virDomainPtr domain, virTypedParameterPtr params, int nparams, unsigned int flags); int virDomainGetNumaParameters(virDomainPtr domain, virTypedParameterPtr params, int *nparams, unsigned int flags); Finally we need a way to associate a domain with a partition virPartitionPtr virDomainGetPartition(virDomainPtr dom, unsigned int flags); void virDomainSetPartition(virDomainPtr dom, unsigned int flags); There'd also likely be a new VM XML element <partition name="..partition name..."/> which is what the Get/SetPartition methods would be touching. Regards, Daniel -- |: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :| |: http://libvirt.org -o- http://virt-manager.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :|