docker-container-top
Display process information inside a Docker container
TLDR
Display the running processes of a container
Display help
SYNOPSIS
docker-container-top [--no-trunc] CONTAINER [ps OPTIONS]
PARAMETERS
--no-trunc
Disable output truncation for long fields
CONTAINER
Name or ID of the target container
ps OPTIONS
Pass-through options from ps command (e.g., -aux, -eo pid,%cpu,cmd)
DESCRIPTION
The docker-container-top command displays a dynamic, real-time list of running processes inside a specified Docker container, akin to the Unix top utility. It shows key metrics like PID, user, CPU time, memory usage, and command for each process, refreshing the display every few seconds for ongoing monitoring.
This tool is essential for container diagnostics, helping identify resource hogs, zombie processes, or anomalies in containerized apps without entering the container via docker exec. It leverages the container runtime's process namespace to fetch data from /proc, ensuring isolation from host processes.
By default, output includes standard columns (PID, USER, TIME, CMD), but users can append ps options for customization, such as sorting by memory (-o %mem) or showing all threads. Ideal for DevOps workflows in Docker Compose, Swarm, or Kubernetes with Docker runtime.
Requires a running container; stopped or exited ones yield no output. On Linux hosts, it's highly efficient; compatibility varies on other platforms.
CAVEATS
Works only on running containers.
Refresh rate fixed (~3s), no interactive sorting.
Dependent on host ps and container runtime support.
Not for Windows/Mac Docker without Linux VM.
COMMON EXAMPLES
docker-container-top myapp
Default top view.
docker-container-top myapp -aux
All processes, user-oriented.
docker-container-top myapp -eo pid,ppid,%cpu,%mem,cmd
Custom CPU/memory columns.
OUTPUT COLUMNS
Typical: PID (process ID), USER (owner), TIME (CPU time), CMD (command).
Customizable via ps -o headers.
HISTORY
Introduced in Docker 0.7.0 (2014) as docker top; evolved with full ps integration by Docker 1.12. Remains stable in Docker CLI v20+ for container introspection.
