CGroup Stats

cgroup-stats is a Go library designed for retrieving CPU and Memory limits information from Linux control groups (cgroups).

NOTE: cgroups v1 is not supported at the moment.

Table of Contents

• CGroup Stats
  • Table of Contents
  • Installation
  • Demo
    • Building the Docker Image
    • Running Without Limits
    • Running With Limits
  • Usage
    • GetCPULimits
    • GetMemoryLimits
  • Example

Installation

To start using cgroup-stats, install Go and run go get:

go get -u github.com/mr-karan/cgroup-stats

Demo

Building the Docker Image

First, build the Docker image using the following command:

docker buildx build -t mrkaran/cgroups -f Dockerfile .

Running Without Limits

Execute the container without any specific CPU or memory limits:

docker run --rm -it mrkaran/cgroups

You should see an output similar to:

Number of CPUs on host: 10
Number of operating system threads: 10
CPU quota is not set
Memory limit is not set

Running With Limits

Now, let's run the container with specific CPU and memory limits. In this case, we're limiting the container to use only half a CPU core (--cpus=0.5) and 1000 MiB of memory (--memory=1000m):

docker run --rm -it --cpus=0.5 --memory=1000m mrkaran/cgroups

You should see an output reflecting the imposed limits:

Number of CPUs on host: 10
Number of operating system threads: 10
CPU quota in the container: 0.500000
Memory limit in the container: 1000.000000 MiB

Usage

cgroup-stats provides easy-to-use functions to retrieve CPU and Memory quota information from cgroups.

GetCPULimits

GetCPULimits function returns the CPU quota assigned to the cgroup.

quota, _ := cgroupstats.GetCPULimits()
fmt.Println("CPU quota in the container:", quota)

GetMemoryLimits

GetMemoryLimits function returns the memory limit assigned to the cgroup.

memQuota, _ := cgroupstats.GetMemoryLimits()
fmt.Println("Memory limit in the container:", memQuota/1048576)

Example

See examples/main.go for a complete example.