Raw cgroups plugin

The cgroups plugin gathers measurements about Linux control groups.

Requirements

Control groups v1 or v2. Some metrics may not be available with cgroups v1.

Metrics

Here are the metrics collected by the plugin's sources.

Name	Type	Unit	Description	Resource	ResourceConsumer	Attributes
`cpu_time_delta`	Delta	nanoseconds	time spent by the pod executing on the CPU	`LocalMachine`	`Cgroup`	see below
`cpu_percent`	Gauge	Percent (0 to 100)	`cpu_time_delta / delta_t` (1 core used fully = 100%)	`LocalMachine`	`Cgroup`	see below
`memory_usage`	Gauge	Bytes	total pod's memory usage	`LocalMachine`	`Cgroup`	see below
`cgroup_memory_anonymous`	Gauge	Bytes	anonymous memory usage	`LocalMachine`	`Cgroup`	see below
`cgroup_memory_file`	Gauge	Bytes	memory used to cache filesystem data	`LocalMachine`	`Cgroup`	see below
`cgroup_memory_kernel_stack`	Gauge	Bytes	memory allocated to kernel stacks	`LocalMachine`	`Cgroup`	see below
`cgroup_memory_pagetables`	Gauge	Bytes	memory reserved for the page tables	`LocalMachine`	`Cgroup`	see below

Attributes

The cpu measurements have an additional attribute kind, which can be one of:

total: time spent in kernel and user mode
system: time spent in kernel mode only
user: time spent in user mode only

Configuration

Here is an example of how to configure this plugin. Put the following in the configuration file of the Alumet agent (usually alumet-config.toml).

[plugins.cgroups]
# Interval between each measurement.
poll_interval = "1s"

Automatic Detection

The version of the control groups and the mount point of the cgroupfs are automatically detected.

The plugin watches for the creation and deletion of cgroups. With cgroup v2, the detection is almost instantaneous, because it relies on inotify. With cgroup v1, however, cgroups are repeatedly polled. The refresh interval is 30s, and it is currently not possible to change it in the plugin's configuration.

More information

To monitor HPC jobs or Kubernetes pods, use the OAR, Slurm or K8S plugins. They provide more information about the jobs/pods, such as their id.

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