docker-stack.yaml

version: '3.7'

services:
  redis-cluster:
    image: redis:5.0.1-alpine
    volumes:
      - redis-data:/data
    entrypoint:
      - /bin/sh
      - -c
      - |          
          redis_master_init=$$(nslookup tasks.redis-master-init 127.0.0.11 | tail -n +5 | awk '{print $$3}')
          if [ $$redis_master_init ]; then
            master_ip=$$redis_master_init            
          else
            until [ "$$(redis-cli -h redis-sentinel -p 26379 ping)" = "PONG" ]; do
              echo "redis-sentinel is unavailable - sleeping"
              sleep 1
            done
            master_info=$$(redis-cli -h redis-sentinel -p 26379 sentinel get-master-addr-by-name redis-cluster)
            master_ip=$$(echo $$master_info | awk '{print $$1}')            
          fi
          redis-server /etc/redis.conf --slaveof $$master_ip 6379 --appendonly yes
    deploy:
      mode: global
    ports:
      - 6379:6379
    networks:
       - internal
    configs:
      - source: redis-conf-bootstrap
        target: /etc/redis.conf
  redis-sentinel:
    image: redis:5.0.1-alpine
    entrypoint:
      - /bin/sh
      - -c
      - |
          cp /tmp/sentinel.conf /etc/sentinel.conf
          redis_master_init=$$(nslookup tasks.redis-master-init 127.0.0.11 | tail -n +5 | awk '{print $$3}')

          if [ $$redis_master_init ]; then
            sed -i "s/{{ MASTER_IP }}/$$redis_master_init/g" /etc/sentinel.conf            
          else
            sentinel_node_list=$$(nslookup tasks.redis-sentinel 127.0.0.11 | tail -n +5 | awk '{print $$3}')
            for sentinel_node in $$sentinel_node_list; do
                master_info=$$(redis-cli -h $$sentinel_node -p 26379 sentinel get-master-addr-by-name redis-cluster)
                if [ "$$master_info" ]; then
                  master_ip=$$(echo $$master_info | awk '{print $$1}')
                  sed -i "s/{{ MASTER_IP }}/$$master_ip/g" /etc/sentinel.conf  
                  break
                fi
            done
          fi
          redis-server /etc/sentinel.conf --sentinel
    deploy:
      mode: global
    ports:
      - 26379:26379
    networks:
      - internal
    configs:
      - source: sentinel-conf
        target: /tmp/sentinel.conf
configs:
  redis-conf-bootstrap:
    file: redis-bootstrap.conf
  sentinel-conf:
    file: sentinel.conf
networks:
  internal:
    external: true
volumes:
  redis-data:
    external: true