Digest #02 - Introduction to Linux Cgroups
As the adoption of containers in the enterprise continues to grow, the underlying technologies that enable container functionality have become increasingly important. One such critical technology is Linux cgroups (control groups), which provide a mechanism for aggregating and managing system resources.
What are Linux cgroups?
Linux cgroups, or control groups, are a kernel feature that allow processes to be organized into hierarchical groups, with specific resource constraints and priorities. These groups can be used to allocate CPU, memory, disk I/O, and network bandwidth, among other system resources.
In the context of containers, cgroups play a vital role in ensuring that each container has access to the resources it needs, while preventing one container from monopolizing system resources at the expense of others.
By associating a container with a specific cgroup, system administrators can fine-tune the resource allocation for each container, ensuring optimal performance and resource utilization.
How do cgroups work with containers?
When a container is launched, the container runtime, such as Docker or runc, creates a new cgroup for the container's processes. This cgroup is then configured with the appropriate resource limits and parameters, based on the container's resource requirements.
For example, if a container is allocated 2 CPU cores and 4GB of memory, the container runtime will create a new cgroup and set the CPU and memory limits accordingly. As the container's processes run, the kernel will enforce these resource constraints, ensuring that the container does not exceed its allocated resources.
Summing Up
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