Swarm Cluster

Table of Contents Cluster Bootstrap Compose File Format Deploy Step Single Host Swarm Cluster Kubernetes Engine Referensi

Cluster

• Deploy Docker Compose (v3) to Swarm (mode) Cluster

Bootstrap

#!/bin/bash

# vars
[ -z "$NUM_WORKERS" ] && NUM_WORKERS=3

# init swarm (need for service command); if not created
docker node ls 2> /dev/null | grep "Leader"
if [ $? -ne 0 ]; then
  docker swarm init > /dev/null 2>&1
fi

# get join token
SWARM_TOKEN=$(docker swarm join-token -q worker)

# get Swarm master IP (Docker for Mac xhyve VM IP)
SWARM_MASTER=$(docker info --format "{{.Swarm.NodeAddr}}")
echo "Swarm master IP: ${SWARM_MASTER}"
sleep 10

# start Docker registry mirror
docker run -d --restart=always -p 4000:5000 --name v2_mirror \
  -v $PWD/rdata:/var/lib/registry \
  -e REGISTRY_PROXY_REMOTEURL=https://registry-1.docker.io \
  registry:2.5

# run NUM_WORKERS workers with SWARM_TOKEN
for i in $(seq "${NUM_WORKERS}"); do
  # remove node from cluster if exists
  docker node rm --force $(docker node ls --filter "name=worker-${i}" -q) > /dev/null 2>&1
  # remove worker contianer with same name if exists
  docker rm --force $(docker ps -q --filter "name=worker-${i}") > /dev/null 2>&1
  # run new worker container
  docker run -d --privileged --name worker-${i} --hostname=worker-${i} \
    -p ${i}2375:2375 \
    -p ${i}5000:5000 \
    -p ${i}5001:5001 \
    -p ${i}5601:5601 \
    docker:1.13-rc-dind --registry-mirror http://${SWARM_MASTER}:4000
  # add worker container to the cluster
  docker --host=localhost:${i}2375 swarm join --token ${SWARM_TOKEN} ${SWARM_MASTER}:2377
done

# show swarm cluster
printf "\nLocal Swarm Cluster\n===================\n"

docker node ls

# echo swarm visualizer
printf "\nLocal Swarm Visualizer\n===================\n"
docker run -it -d --name swarm_visualizer \
  -p 8000:8080 -e HOST=localhost \
  -v /var/run/docker.sock:/var/run/docker.sock \
  manomarks/visualizer:beta

Compose

File Format

• docker-stack.yml

version: "3"
 
services:
 
  redis:
    image: redis:3.2-alpine
    ports:
      - "6379"
    networks:
      - voteapp
    deploy:
      placement:
        constraints: [node.role == manager]
 
  db:
    image: postgres:9.4
    volumes:
      - db-data:/var/lib/postgresql/data
    networks:
      - voteapp
    deploy:
      placement:
        constraints: [node.role == manager]
 
  voting-app:
    image: gaiadocker/example-voting-app-vote:good
    ports:
      - 5000:80
    networks:
      - voteapp
    depends_on:
      - redis
    deploy:
      mode: replicated
      replicas: 2
      labels: [APP=VOTING]
      placement:
        constraints: [node.role == worker]
 
  result-app:
    image: gaiadocker/example-voting-app-result:latest
    ports:
      - 5001:80
    networks:
      - voteapp
    depends_on:
      - db
 
  worker:
    image: gaiadocker/example-voting-app-worker:latest
    networks:
      voteapp:
        aliases:
          - workers
    depends_on:
      - db
      - redis
    # service deployment
    deploy:
      mode: replicated
      replicas: 2
      labels: [APP=VOTING]
      # service resource management
      resources:
        # Hard limit - Docker does not allow to allocate more
        limits:
          cpus: '0.25'
          memory: 512M
        # Soft limit - Docker makes best effort to return to it
        reservations:
          cpus: '0.25'
          memory: 256M
      # service restart policy
      restart_policy:
        condition: on-failure
        delay: 5s
        max_attempts: 3
        window: 120s
      # service update configuration
      update_config:
        parallelism: 1
        delay: 10s
        failure_action: continue
        monitor: 60s
        max_failure_ratio: 0.3
      # placement constraint - in this case on 'worker' nodes only
      placement:
        constraints: [node.role == worker]
 
networks:
    voteapp:
 
volumes:

Deploy Step

• GitHub: Example-app
• Deploy to Docker Swarm with a YML ste

Single Host

docker-compose up

Swarm Cluster

docker stack deploy --compose-file docker-stack.yml vote

Kubernetes Engine

• Set Kubernetes Cluster configuration manually

$ kubectl create namespace vote

Referensi

• How to disable docker swarm mode?