版权声明：本文为博主原创文章，未经博主允许不得转载。 https://blog.csdn.net/huangjun0210/article/details/86502021
Docker Swarm（四）：Docker Stack 部署多服务集群
1. Docker Stack简介
单机模式下，我们可以使用 Docker Compose 来编排多个服务，而 Docker Swarm 只能实现对单个服务的简单部署。本文的主角 Docker Stack ，通过 Docker Stack 我们只需对已有的 docker-compose.yml 配置文件稍加改造就可以完成 Docker 集群环境下的多服务编排。
2. Docker Stack集群搭建案例
部署一个投票APP，包含如下服务：
- 5个应用服务：vote、redis、worker，db，result
- 工具服务：portainer 和 visualizer
首先创建一个 docker-compose.yml 文件，使用 Docker Compose v3 语法
version: "3"
services:
redis:
image: redis:alpine
ports:
- "6379"
networks:
- frontend
deploy:
replicas: 2
update_config:
parallelism: 2
delay: 10s
restart_policy:
condition: on-failure
db:
image: postgres:9.4
volumes:
- db-data:/var/lib/postgresql/data
networks:
- backend
deploy:
placement:
constraints: [node.role == manager]
vote:
image: dockersamples/examplevotingapp_vote:before
ports:
- 5000:80
networks:
- frontend
depends_on:
- redis
deploy:
replicas: 2
update_config:
parallelism: 2
restart_policy:
condition: on-failure
result:
image: dockersamples/examplevotingapp_result:before
ports:
- 5001:80
networks:
- backend
depends_on:
- db
deploy:
replicas: 1
update_config:
parallelism: 2
delay: 10s
restart_policy:
condition: on-failure
worker:
image: dockersamples/examplevotingapp_worker
networks:
- frontend
- backend
deploy:
mode: replicated
replicas: 1
labels: [APP=VOTING]
restart_policy:
condition: on-failure
delay: 10s
max_attempts: 3
window: 120s
placement:
constraints: [node.role == manager]
visualizer:
image: dockersamples/visualizer:stable
ports:
- "8080:8080"
stop_grace_period: 1m30s
volumes:
- "/var/run/docker.sock:/var/run/docker.sock"
deploy:
placement:
constraints: [node.role == manager]
portainer:
image: portainer/portainer
ports:
- "9000:9000"
volumes:
- "/var/run/docker.sock:/var/run/docker.sock"
deploy:
replicas: 1
placement:
constraints: [node.role == manager]
networks:
frontend:
backend:
volumes:
db-data:
在manager节点部署服务：
[root@swarm-manager example-voting-app]# docker stack deploy example --compose-file=docker-compose.yml
Creating network example_frontend
Creating network example_default
Creating network example_backend
Creating service example_result
Creating service example_worker
Creating service example_visualizer
Creating service example_portainer
Creating service example_redis
Creating service example_db
Creating service example_vote
部署完成：
[root@swarm-manager example-voting-app]# docker stack services example
ID NAME MODE REPLICAS IMAGE PORTS
cdmrhfag3zje example_vote replicated 2/2 dockersamples/examplevotingapp_vote:before *:5000->80/tcp
csjcltpwvpzs example_visualizer replicated 1/1 dockersamples/visualizer:stable *:8080->8080/tcp
ihys1qvpz4i5 example_worker replicated 1/1 dockersamples/examplevotingapp_worker:latest
l0ufhl8n0ozg example_portainer replicated 1/1 portainer/portainer:latest *:9000->9000/tcp
m2icguw00ls9 example_db replicated 1/1 postgres:9.4
pu2h7rqzpaa0 example_redis replicated 2/2 redis:alpine *:30001->6379/tcp
tom14od7paf1 example_result replicated 1/1 dockersamples/examplevotingapp_result:before *:5001->80/tcp
[root@swarm-manager example-voting-app]# docker stack ps example
ID NAME IMAGE NODE DESIRED STATE CURRENT STATE ERROR PORTS
loj1h2dk9l1s example_vote.1 dockersamples/examplevotingapp_vote:before swarm-worker3 Running Running 2 minutes ago
kp4n980ldv49 example_db.1 postgres:9.4 swarm-manager Running Running 2 minutes ago
0hf6d80nwwyf example_worker.1 dockersamples/examplevotingapp_worker:latest swarm-manager Running Running 2 minutes ago
rnjnwhl86ro6 example_redis.1 redis:alpine swarm-worker1 Running Running 2 minutes ago
1376pp1lvrly example_portainer.1 portainer/portainer:latest swarm-manager Running Running 2 minutes ago
xj9a9iu9g2s8 example_worker.1 dockersamples/examplevotingapp_worker:latest swarm-manager Shutdown Failed 2 minutes ago "task: non-zero exit (1)"
g5ts3oiibrhn example_visualizer.1 dockersamples/visualizer:stable swarm-manager Running Running 3 minutes ago
kgcttt1xigu2 example_worker.1 dockersamples/examplevotingapp_worker:latest swarm-manager Shutdown Failed 3 minutes ago "task: non-zero exit (1)"
jpqdinh0st7b \_ example_worker.1 dockersamples/examplevotingapp_worker:latest swarm-manager Shutdown Failed 3 minutes ago "task: non-zero exit (1)"
ff9bq1vcgbz9 example_result.1 dockersamples/examplevotingapp_result:before swarm-manager Running Running 2 minutes ago
q27wp9nna0yc example_vote.2 dockersamples/examplevotingapp_vote:before swarm-worker1 Running Running 2 minutes ago
s6hvxlgdz77v example_redis.2 redis:alpine swarm-worker2 Running Running 2 minutes ago
浏览器访问：
vote ip:5000
result ip:5001
portainer ip:9000
visualizer ip:8080
3. Docker Stack和Docker Compose区别
- Docker stack会忽略了“构建”指令，无法使用stack命令构建新镜像，它是需要镜像是预先已经构建好的。 所以docker-compose更适合于开发场景；
- Docker Compose是一个Python项目，在内部，它使用Docker API规范来操作容器。所以需要安装Docker -compose，以便与Docker一起在您的计算机上使用；
- Docker Stack功能包含在Docker引擎中。你不需要安装额外的包来使用它，docker stacks 只是swarm mode的一部分。
- Docker stack不支持基于第2版写的docker-compose.yml ，也就是version版本至少为3。然而Docker Compose对版本为2和3的 文件仍然可以处理；
- docker stack把docker compose的所有工作都做完了，因此docker stack将占主导地位。同时，对于大多数用户来说，切换到使用docker stack既不困难，也不需要太多的开销。如果您是Docker新手，或正在选择用于新项目的技术，请使用docker stack。
4. Docker Stack常用命令
| 命令 | 描述 |
|---|---|
| docker stack deploy | 部署新的堆栈或更新现有堆栈 |
| docker stack ls | 列出现有堆栈 |
| docker stack ps | 列出堆栈中的任务 |
| docker stack rm | 删除一个或多个堆栈 |
| docker stack services | 列出堆栈中的服务 |