The example of canary deployment using Traefik 2.x

stack-canary.yml

# docker stack deploy -c stack-canary.yml canary --with-registry-auth --prune
version: "3.7"

services:
  app1:
    image: jakubhajek/app1-node:v1
    healthcheck:
      test: wget --quiet --tries=1 --spider http://localhost:3000/ || exit 1
      interval: 3s
      timeout: 1s
      retries: 1
      start_period: 5s
    networks:
      - proxy-main
    deploy:
      mode: replicated
      replicas: 2
      update_config:
        failure_action: rollback
        parallelism: 1
        delay: 5s
      restart_policy:
        condition: on-failure
        delay: 5s
        max_attempts: 3
      resources:
        limits:
          memory: 128M
      labels:
        - "traefik.enable=true"
        - "traefik.http.routers.app1.rule=Host(`canary.labs.cometari.eu`)"
        - "traefik.http.routers.app1.tls.certresolver=le"
        - "traefik.http.routers.app1.entrypoints=websecure"

        # Canary approach
        - "traefik.http.routers.app1.service=canary@file"

        - "traefik.http.services.app1_svc.loadbalancer.server.port=3000"

  app2:
    image: jakubhajek/app1-node:v2
    healthcheck:
      test: wget --quiet --tries=1 --spider http://localhost:3000/ || exit 1
      interval: 3s
      timeout: 1s
      retries: 1
      start_period: 5s
    networks:
      - proxy-main
    deploy:
      mode: replicated
      replicas: 2
      resources:
        limits:
          memory: 128M
      labels:
        - "traefik.enable=true"
        - "traefik.http.services.app2_svc.loadbalancer.server.port=3000"

networks:
  proxy-main:
    external: true