cgroupspy

Python library for managing cgroups

The library provides a pythonic way to manage and represent cgroups. It provides interfaces that convert python objects to cgroups compatible strings and vise versa.

Trees

cgroupspy has a couple of ways to represent the cgroups filesystem

• As a tree - this is the most basic and generic way to represent them. You basically construct it from all the directories in the cgroups root.

• A grouped tree - that has access to all cgroup partitions with the same name, on the same level. For example - 'machine' partition in memory, cpuset, cpus, etc cgroups. All these attributes are accessed via machine.cpus, machine.cpuset, etc.

• A VMTree - a subclass of grouped tree with utilities for simple management of libvirt guests

Example usage

#Import the trees module, which contains a tree representation of cgroups>>>fromcgroupspyimporttrees# This is the most basic type of cgroup tree. It models the filesystem.>>>t=trees.Tree()
# It has a root which is of type Node>>>t.root<Node/># And the root has children>>>print(t.root.children)
[<Node/hugetlb>, <Node/net_prio>, <Node/perf_event>, <Node/blkio>, <Node/net_cls>, <Node/freezer>, <Node/devices>, <Node/memory>, <Node/cpuacct>, <Node/cpu>, <Node/cpuset>, <Node/systemd>, <Node/cgmanager>]
# You can for example get the cpuset>>>cset=t.get_node_by_path('/cpuset/')
>>>cset<Node/cpuset># The controller used for this cgroup is a CpuSetController>>>cset.controller<cgroupspy.controllers.CpuSetControllerobjectat0x7f63a3843050># Which can for example show you the cpu pinning>>>cset.controller.cpusset([0, 1])
# You can create a cgroup>>>test=cset.create_cgroup('test')
<Node/cpuset/test># See its cpu restrictions>>>test.controller.cpusset([0, 1])
# And change them>>>test.controller.cpus= [1]
# The tasks in this cgroup are now restricted to cpu 1>>>test.controller.cpusset([1])

Another example with the VMTree - for managing libvirt guests

>>>fromcgroupspy.treesimportVMTree>>>vmt=VMTree()
>>>print(vmt.vms)
{u'1ce10f47-fb4e-4b6a-8ee6-ba34940cdda7.libvirt-qemu': <NodeVM1ce10f47-fb4e-4b6a-8ee6-ba34940cdda7.libvirt-qemu>,
u'3d5013b9-93ed-4ef1-b518-a2cea43f69ad.libvirt-qemu': <NodeVM3d5013b9-93ed-4ef1-b518-a2cea43f69ad.libvirt-qemu>,
}
>>>vm=vmt.get_vm_node("1ce10f47-fb4e-4b6a-8ee6-ba34940cdda7")
>>>print(vm.cpu.shares)
1024>>>print(vm.cpuset.cpus)
{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15}
>>>print(vm.memory.limit_in_bytes)
25603080192>>>print(vm.children)
[<NodeControlGroupvcpu1>,
<NodeControlGroupvcpu0>,
<NodeControlGroupemulator>]
>>>print(vm.path)
/machine/grey/1ce10f47-fb4e-4b6a-8ee6-ba34940cdda7.libvirt-qemu>>>vcpu1=vm.children[0]
>>>print(vcpu1.cpuset.cpus)
{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15}
>>>vcpu1.cpuset.cpus= {1,2,3}
>>>print(vcpu1.cpuset.cpus)
{1, 2, 3}

License

new BSD licence