Docker Compose Performance Tuning

1# BAD: Full OS images
2services: 
3  app: 
4    image: ubuntu:22.04  # 77MB
5
6# GOOD: Minimal images
7services: 
8  app: 
9    image: alpine:3.19   # 7MB
10
11# BETTER: Distroless (for compiled apps)
12# FROM gcr.io/distroless/static  # ~2MB
13
14# Compare image sizes
15docker images --format "table {{.Repository}}: {{.Tag}}	{{.Size}}"
16
17# Common lightweight alternatives:
18# python:3.11        -> python:3.11-slim or python:3.11-alpine
19# node:20            -> node:20-slim or node:20-alpine
20# postgres:15        -> postgres:15-alpine
21# nginx:latest       -> nginx:alpine

1services: 
2  app: 
3    image: myapp:1.0
4    deploy: 
5      resources: 
6        limits: 
7          cpus: '2'         # Max 2 CPU cores
8          memory: 1G        # Max 1GB RAM
9        reservations: 
10          cpus: '0.5'       # Guaranteed 0.5 cores
11          memory: 256M      # Guaranteed 256MB RAM
12
13  # Database with higher memory
14  postgres: 
15    image: postgres:15-alpine
16    deploy: 
17      resources: 
18        limits: 
19          cpus: '2'
20          memory: 2G
21        reservations: 
22          memory: 512M
23    # Postgres-specific tuning in postgresql.conf

1# Real-time container stats
2docker stats
3
4# Container-specific detailed stats
5docker stats --no-stream --format "table {{.Name}}	{{.CPUPerc}}	{{.MemUsage}}	{{.NetIO}}	{{.BlockIO}}"
6
7# Historical monitoring with ctop
8docker run --rm -it \
9    -v /var/run/docker.sock:/var/run/docker.sock \
10    quay.io/vektorlab/ctop
11
12# Or use Prometheus + Grafana stack
13services:
14  cadvisor:
15    image: gcr.io/cadvisor/cadvisor:latest
16    volumes:
17      - /:/rootfs:ro
18      - /var/run:/var/run:ro
19      - /sys:/sys:ro
20      - /var/lib/docker/:/var/lib/docker:ro

1# Check current storage driver
2docker info | grep "Storage Driver"
3# overlay2 is recommended for most setups
4
5# For database workloads, use named volumes with proper mount options
6services: 
7  postgres: 
8    volumes: 
9      - type: volume
10        source: postgres_data
11        target: /var/lib/postgresql/data
12        volume: 
13          nocopy: true  # Skip initial copy, faster start
14
15volumes: 
16  postgres_data: 
17    driver: local
18    driver_opts: 
19      type: none
20      device: /mnt/fast-ssd/postgres  # Put on fast storage
21      o: bind
22
23# Avoid storing database data on overlay filesystem
24# Use bind mounts to fast local storage

1# For maximum network performance: host mode
2# (Removes network isolation!)
3services: 
4  high-perf-app: 
5    network_mode: host
6
7# For bridge mode, use custom networks with optimal settings
8networks: 
9  optimized: 
10    driver: bridge
11    driver_opts: 
12      com.docker.network.driver.mtu: 9000  # Jumbo frames if supported
13
14# Enable IPv6 if needed (can improve certain workloads)
15# In /etc/docker/daemon.json:
16{
17  "ipv6": true,
18  "fixed-cidr-v6": "fd00::/64"
19}

1services: 
2  high-volume-app: 
3    logging: 
4      driver: "local"  # Faster than json-file
5      options: 
6        max-size: "10m"
7        max-file: "3"
8        compress: "true"
9
10  # For apps where you don't need logs in Docker
11  batch-job: 
12    logging: 
13      driver: "none"  # Completely disable
14
15# Global configuration in /etc/docker/daemon.json
16{
17  "log-driver": "local",
18  "log-opts": {
19    "max-size": "10m",
20    "max-file": "3"
21  }
22}

1services: 
2  app: 
3    depends_on: 
4      db: 
5        condition: service_healthy  # Wait for DB to be ready
6    # Don't wait for everything, just essentials
7
8  db: 
9    image: postgres:15-alpine
10    healthcheck: 
11      test: ["CMD-SHELL", "pg_isready -U postgres"]
12      interval: 2s    # Check frequently
13      timeout: 1s     # Fail fast
14      retries: 10     # Allow slow starts
15      start_period: 5s
16
17# Parallel startup where possible
18# Services without dependencies start simultaneously
19
20# Avoid unnecessary restarts
21restart: unless-stopped
22# Not 'always' - prevents restart loops

1services: 
2  postgres: 
3    image: postgres:15-alpine
4    environment: 
5      # Basic performance tuning
6      - POSTGRES_INITDB_ARGS=--data-checksums
7    volumes: 
8      - ./postgresql.conf:/etc/postgresql/postgresql.conf:ro
9    command: postgres -c config_file=/etc/postgresql/postgresql.conf
10
11# postgresql.conf tuning for 4GB RAM server:
12# shared_buffers = 1GB           # 25% of RAM
13# effective_cache_size = 3GB     # 75% of RAM
14# work_mem = 64MB
15# maintenance_work_mem = 256MB
16# max_connections = 100
17
18  redis: 
19    image: redis:alpine
20    command: redis-server --maxmemory 256mb --maxmemory-policy allkeys-lru
21
22  mysql: 
23    image: mysql:8
24    command: --innodb-buffer-pool-size=1G --innodb-log-file-size=256M

1services: 
2  app: 
3    environment: 
4      - REDIS_URL=redis://redis:6379
5    depends_on: 
6      - redis
7
8  redis: 
9    image: redis:alpine
10    command: >
11      redis-server
12      --maxmemory 512mb
13      --maxmemory-policy allkeys-lru
14      --appendonly no
15    volumes: 
16      - redis_data:/data
17    deploy: 
18      resources: 
19        limits: 
20          memory: 768M  # More than maxmemory for overhead
21
22  # Or use Varnish for HTTP caching
23  varnish: 
24    image: varnish:stable
25    volumes: 
26      - ./default.vcl:/etc/varnish/default.vcl:ro
27    environment: 
28      - VARNISH_SIZE=256M
29
30volumes: 
31  redis_data: 

1# /etc/docker/daemon.json
2{
3  "storage-driver": "overlay2",
4  "log-driver": "local",
5  "log-opts": {
6    "max-size": "10m",
7    "max-file": "3"
8  },
9  "default-ulimits": {
10    "nofile": {
11      "Name": "nofile",
12      "Hard": 65536,
13      "Soft": 65536
14    }
15  },
16  "live-restore": true,
17  "userland-proxy": false,
18  "default-shm-size": "128M"
19}
20
21# Apply changes
22sudo systemctl restart docker
23
24# Verify
25docker info

1# Lightweight monitoring stack
2services: 
3  prometheus: 
4    image: prom/prometheus:latest
5    volumes: 
6      - ./prometheus.yml:/etc/prometheus/prometheus.yml
7      - prometheus_data:/prometheus
8    command: 
9      - '--config.file=/etc/prometheus/prometheus.yml'
10      - '--storage.tsdb.retention.time=15d'
11
12  grafana: 
13    image: grafana/grafana:latest
14    volumes: 
15      - grafana_data:/var/lib/grafana
16    environment: 
17      - GF_SECURITY_ADMIN_PASSWORD=${GRAFANA_PASSWORD}
18
19  node-exporter: 
20    image: prom/node-exporter:latest
21    pid: host
22    volumes: 
23      - /proc:/host/proc:ro
24      - /sys:/host/sys:ro
25    command: 
26      - '--path.procfs=/host/proc'
27      - '--path.sysfs=/host/sys'
28
29volumes: 
30  prometheus_data: 
31  grafana_data: