Konteyner Loglama: Docker ve Kubernetes Log Yönetimi

# Konteyner loglarını görüntüle
docker logs CONTAINER_NAME

# Son N satırı görüntüle
docker logs --tail 100 CONTAINER_NAME

# Canlı log takibi
docker logs -f CONTAINER_NAME

# Zaman damgası ile görüntüle
docker logs -t CONTAINER_NAME

# Belirli zamandan itibaren
docker logs --since 2024-01-01T00:00:00 CONTAINER_NAME
docker logs --since 1h CONTAINER_NAME  # Son 1 saat

# Belirli zaman aralığı
docker logs --since 2h --until 1h CONTAINER_NAME

# Canlı + zaman damgası
docker logs -f -t CONTAINER_NAME

# Mevcut log sürücüsünü kontrol et
docker info | grep 'Logging Driver'

# Konteyner log sürücüsünü görüntüle
docker inspect CONTAINER_NAME | grep LogConfig -A 5

// /etc/docker/daemon.json
{
  "log-driver": "json-file",
  "log-opts": {
    "max-size": "10m",
    "max-file": "3",
    "compress": "true"
  }
}

# Docker daemon'ı yeniden başlat
systemctl restart docker

# json-file ile log rotasyonu
docker run -d \
  --name myapp \
  --log-driver json-file \
  --log-opt max-size=10m \
  --log-opt max-file=3 \
  myapp:latest

# Syslog'a yönlendir
docker run -d \
  --name myapp \
  --log-driver syslog \
  --log-opt syslog-address=udp://localhost:514 \
  myapp:latest

# Loglama devre dışı (performans kritik)
docker run -d \
  --name myapp \
  --log-driver none \
  myapp:latest

# docker-compose.yml
version: '3.8'

services:
  app:
    image: myapp:latest
    logging:
      driver: json-file
      options:
        max-size: "10m"
        max-file: "5"
        compress: "true"
        labels: "app,environment"
    labels:
      - "app=myapp"
      - "environment=production"

  nginx:
    image: nginx:latest
    logging:
      driver: json-file
      options:
        max-size: "5m"
        max-file: "3"

# Pod loglarını görüntüle
kubectl logs POD_NAME

# Belirli container'ın logları (multi-container pod)
kubectl logs POD_NAME -c CONTAINER_NAME

# Canlı log takibi
kubectl logs -f POD_NAME

# Son N satır
kubectl logs --tail=100 POD_NAME

# Belirli zamandan itibaren
kubectl logs --since=1h POD_NAME

# Önceki container'ın logları (crash sonrası)
kubectl logs --previous POD_NAME

# Deployment'taki tüm pod'ların logları
kubectl logs -l app=myapp --all-containers

# Namespace belirterek
kubectl logs -n production POD_NAME

# loki-stack.yml
version: '3.8'

services:
  loki:
    image: grafana/loki:latest
    ports:
      - "3100:3100"
    volumes:
      - loki-data:/loki
    command: -config.file=/etc/loki/local-config.yaml

  promtail:
    image: grafana/promtail:latest
    volumes:
      - /var/log:/var/log:ro
      - /var/lib/docker/containers:/var/lib/docker/containers:ro
      - ./promtail-config.yml:/etc/promtail/config.yml
    command: -config.file=/etc/promtail/config.yml

  grafana:
    image: grafana/grafana:latest
    ports:
      - "3000:3000"
    environment:
      - GF_SECURITY_ADMIN_PASSWORD=GucluSifre123!
    volumes:
      - grafana-data:/var/lib/grafana

volumes:
  loki-data:
  grafana-data:

# promtail-config.yml
server:
  http_listen_port: 9080
  grpc_listen_port: 0

positions:
  filename: /tmp/positions.yaml

clients:
  - url: http://loki:3100/loki/api/v1/push

scrape_configs:
  - job_name: docker
    docker_sd_configs:
      - host: unix:///var/run/docker.sock
        refresh_interval: 5s
    relabel_configs:
      - source_labels: ['__meta_docker_container_name']
        regex: '/(.*?)'
        target_label: 'container'
      - source_labels: ['__meta_docker_container_log_stream']
        target_label: 'logstream'

# Loki Docker plugin kur
docker plugin install grafana/loki-docker-driver:latest \
  --alias loki \
  --grant-all-permissions

# Konteyner başlatırken Loki'ye gönder
docker run -d \
  --name myapp \
  --log-driver loki \
  --log-opt loki-url="http://localhost:3100/loki/api/v1/push" \
  --log-opt loki-batch-size=400 \
  myapp:latest

// /etc/docker/daemon.json — Tüm konteynerler için Loki
{
  "log-driver": "loki",
  "log-opts": {
    "loki-url": "http://localhost:3100/loki/api/v1/push",
    "loki-batch-size": "400",
    "loki-retries": "3",
    "loki-max-backoff": "800ms",
    "loki-timeout": "1s"
  }
}

# fluent-bit-daemonset.yaml
apiVersion: apps/v1
kind: DaemonSet
metadata:
  name: fluent-bit
  namespace: kube-system
spec:
  selector:
    matchLabels:
      app: fluent-bit
  template:
    metadata:
      labels:
        app: fluent-bit
    spec:
      containers:
      - name: fluent-bit
        image: fluent/fluent-bit:latest
        volumeMounts:
        - name: varlog
          mountPath: /var/log
        - name: varlibdockercontainers
          mountPath: /var/lib/docker/containers
          readOnly: true
        - name: fluent-bit-config
          mountPath: /fluent-bit/etc/
      volumes:
      - name: varlog
        hostPath:
          path: /var/log
      - name: varlibdockercontainers
        hostPath:
          path: /var/lib/docker/containers
      - name: fluent-bit-config
        configMap:
          name: fluent-bit-config

# Docker log dosyalarının boyutunu kontrol et
du -sh /var/lib/docker/containers/*/*-json.log

# Tüm konteyner loglarını temizle (dikkatli!)
truncate -s 0 /var/lib/docker/containers/*/*-json.log

# Belirli konteynerin logunu temizle
truncate -s 0 $(docker inspect --format='{{.LogPath}}' CONTAINER_NAME)

# Logrotate ile otomatik rotasyon
cat > /etc/logrotate.d/docker-containers << 'EOF'
/var/lib/docker/containers/*/*.log {
  rotate 7
  daily
  compress
  size=10M
  missingok
  delaycompress
  copytruncate
}
EOF

// Node.js — Winston ile JSON loglama
const winston = require('winston');

const logger = winston.createLogger({
  level: 'info',
  format: winston.format.combine(
    winston.format.timestamp(),
    winston.format.errors({ stack: true }),
    winston.format.json()
  ),
  transports: [
    new winston.transports.Console()
  ]
});

// Kullanım
logger.info('Kullanıcı girişi', {
  userId: 123,
  action: 'login',
  ip: '192.168.1.1'
});

logger.error('Veritabanı hatası', {
  error: err.message,
  query: 'SELECT * FROM users'
});