Cgroup
A cgroup is a Linux kernel mechanism that groups processes to control, limit, isolate, and account for their resource usage.
Podman in Action: Secure, rootless containers for Kubernetes, microservices, and more
A Linux kernel mechanism for grouping processes and limiting or accounting for their resource usage.
- How it is used
- Constrains and monitors process-group resources to prevent container workloads from exhausting shared system capacity.
- How deep it goes
- Defines hierarchical grouping and names resource examples, then connects cgroups to pods and systemd process tracking.
- Examples
- Uses memory, CPU, and network constraints, pod-level sharing, and systemd service scopes as concrete examples.
- What you can do after
- Operate and configure Podman services with systemd while understanding cgroup-based resource and process management.
Kubernetes in Action, Second Edition
A cgroup is a Linux kernel mechanism that groups processes and limits, accounts for, and isolates their use of resources such as CPU, memory, and bandwidth.
- How it is used
- Protects critical processes and containers by controlling their CPU, memory, disk, and network resource consumption.
- How deep it goes
- Defines resource control and demonstrates Docker limits, but stops short of explaining cgroup internals.
- Examples
- Demonstrates Docker commands for selecting CPU cores, limiting CPU time, and setting container memory limits.
- What you can do after
- Apply cgroups through Docker options to constrain a container's CPU and memory consumption.
Read how Kubernetes in Action, Second Edition explains cgroup →
Acing the Certified Kubernetes Administrator Exam, Second Edition
A cgroup is a Linux kernel mechanism for organizing and controlling processes and their resource consumption.
- How it is used
- Explains how kind layers Linux cgroups and namespaces to isolate Kubernetes containers inside Docker-based nodes.
- How deep it goes
- Connects cgroups to nested node and pod isolation and kubelet startup, but does not detail cgroup configuration or resource-limit syntax.
- Examples
- Uses kind-control-plane and kind-worker containers, kubectl node output, Docker inspection, and kubelet service status.
- What you can do after
- Evaluate layered container isolation by inspecting kind nodes, runtimes, kernels, and kubelet cgroup initialization.
Read how Acing the Certified Kubernetes Administrator Exam, Second Edition explains cgroup →
Related concepts
- containerused by · A software container is an isolated execution environment that packages an application and its dependencies while sharing the host operating system kernel.
- Dockerconfigured by · Docker is a platform and ecosystem for building, distributing, and running applications in containers.
- linux namespacecontrasts with · A Linux namespace is a kernel mechanism that gives processes isolated views of selected system resources, such as processes, networks, or filesystem mounts.
- operating system kernelkind of · An operating system kernel is privileged core software that manages hardware and system resources while providing fundamental services to other software.
- Linuxpart of · Linux is an open-source operating-system kernel and the family of Unix-like operating systems built around it.
- podused by · A Kubernetes Pod is the smallest deployable unit in Kubernetes, grouping one or more co-located containers that share networking and other resources.
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