Immanuelbint Docs

Appearance

Automating Docker Resource Management ​

Problem ​

Containers without resource limits can consume system memory and CPU without restriction, causing host-level performance issues.

Goal ​

Provide a quick CLI tool for setting, monitoring, and resetting CPU/memory limits on Docker containers interactively.

Solution – Bash Menu Script ​

Features: ​

  • Limit CPU usage by core
  • Limit memory and swap
  • Monitor resource usage live (docker stats)
  • Reset all limitations

Script Example ​

bash
#!/bin/bash
# Setup logging
function log() {
  if [[ -n "${LOG:-}" ]]; then
    printf '%s\n' "$*" | tee -a "$LOG" >&2
  else
    printf '%s\n' "$*" >&2
  fi
}
function fatal() { log "ERROR: $*"; exit 1; }

menu="
Enter menu you'd like to use :
1. Limit CPU Docker Container
2. Limit Memory Docker Container
3. Monitor Docker Container
4. Reset CPU + Memory limitation
==============================
q: quit the script

=> "

## Function limit memory docker container
function limit_memory_docker() {
    read -r -p "Set memory limit (e.g. 4g, 512m): " memlimit
    read -r -p "Set total memory + swap limit (e.g. 6g, 1g): " swaplimit
    read -r -p "Enter Docker container name or ID to apply limit: " containername
    docker update --memory "$memlimit" --memory-swap "$swaplimit" "$containername" && \
    log "INFO: Successfully updated memory limits for container: $containername"
}
## Function limit cpu docker container
function limit_cpu_docker() {
    read -r -p "Set CPU cores to allow (e.g. 0-1, 2 for core #2): " cpulimit
    read -r -p "Enter Docker container name or ID to apply limit: " containername
    docker update  --cpuset-cpus "$cpulimit" "$containername" && \
    log "INFO: Successfully updated CPU core assignment for container: $containername"
}
## Function to reset cpu/memory limitation
function reset_limit_docker() {
    read -r -p "Enter Docker container name or ID you'd like to reset limitation: " containername
    docker update --cpuset-cpus="" --memory="" --memory-swap="" "$containername" && \
    log "INFO: Successfully reset CPU + Memory limitation for container: $containername"
}

## Function monitor docker container
function monitor_docker() {
    docker container stats
}

## Main Program
while true; do
read -p "$menu" choice
case $choice in
    1) limit_cpu_docker ;;
    2) limit_memory_docker  ;;
    3) monitor_docker ;;
    4) reset_limit_docker ;;
    q) exit 0 ;;
    *) log "Oops, Invalid choice";;
  esac
done

Usage ​

  1. Save as docker-limiter.sh
  2. Make executable:
bash
chmod +x docker-limiter.sh
  1. Run the script:
bash
bash docker-limiter.sh

Notes and Improvements ​

  • Script assumes Docker is already installed and the user has appropriate permissions.

  • Future improvements:

    • Add CPU quota limits (--cpu-quota, --cpu-period)
    • Include container auto-complete
    • Add logging feature for changes