6.1 业务背景
6.2 Docker传统方式实现
6.3 简介和安装
- 6.3.1 简介
- 6.3.2 安装
6.4 docker compose实现
- 6.4.1 同样的前期准备
- 6.4.2 编写docker-compose.yaml文件
6.5 详解docker-compose.yml文件
6.6 docker-compose常见操作
6.7 scale扩缩容
07 Docker Swarm

官网：https://docs.docker.com/compose/

6.1 业务背景

6.2 Docker传统方式实现

6.2.1 写Python代码&build image

(1)创建文件夹

mkdir -p /tmp/composetest
cd /tmp/composetest

(2)创建app.py文件，写业务内容

import time
import redis
from flask import Flask
app = Flask(__name__)
cache = redis.Redis(host='redis', port=6379)
def get_hit_count():
    retries = 5
    while True:
        try:
            return cache.incr('hits')
        except redis.exceptions.ConnectionError as exc:
            if retries == 0:
                raise exc
            retries -= 1
            time.sleep(0.5)
@app.route('/')
def hello():
    count = get_hit_count()
    return 'Hello World! I have been seen {} times.\n'.format(count)

(3)新建requirements.txt文件

flask
redis

(4)编写Dockerfile

FROM python:3.7-alpine
WORKDIR /code
ENV FLASK_APP app.py
ENV FLASK_RUN_HOST 0.0.0.0
RUN apk add --no-cache gcc musl-dev linux-headers
COPY requirements.txt requirements.txt
RUN pip install -r requirements.txt
COPY . .
CMD ["flask", "run"]

(5)根据Dockerfile生成image

docker build -t python-app-image .

(6)查看images：docker images

python-app-image latest 7e1d81f366b7 3 minutes ago  213MB

6.2.2 获取Redis的image

docker pull redis:alpine

6.2.3 创建两个container

(1)创建网络

docker network ls
docker network create --subnet=172.20.0.0/24 app-net

(1)创建python程序的container，并指定网段和端口

docker run -d --name web -p 5000:5000 --network app-net python-app-image

(2)创建redis的container，并指定网段

docker run -d --name redis --network app-net redis:alpine

6.2.4 访问测试

ip[centos]:5000

6.3 简介和安装

6.3.1 简介

官网：https://docs.docker.com/compose/

Compose is a tool for defining and running multi-container Docker applications. With Compose, you use a YAML file to configure your application’s services. Then, with a single command, you create and start all the services from your configuration.

6.3.2 安装

Linux环境中需要单独安装

官网：https://docs.docker.com/compose/install/

sudo curl -L "https://github.com/docker/compose/releases/download/1.24.1/docker-compose-$(uname -s)-$(uname -m)" -o /usr/local/bin/docker-compose

sudo chmod +x /usr/local/bin/docker-compose

6.4 docker compose实现

reference：https://docs.docker.com/compose/gettingstarted/

6.4.1 同样的前期准备

新建目录，比如composetest

进入目录，编写app.py代码

创建requirements.txt文件

编写Dockerfile

6.4.2 编写docker-compose.yaml文件

默认名称，当然也可以指定，docker-compose.yaml

version: '3'
services:
  web:
    build: .
    ports:
      - "5000:5000"
    networks:
      - app-net
  redis:
    image: "redis:alpine"
    networks:
      - app-net
networks:
  app-net:
    driver: bridge

(1)通过docker compose创建容器

docker-compose up -d

(2)访问测试

6.5 详解docker-compose.yml文件

(1)version: ‘3’

表示docker-compose的版本

(2)services

一个service表示一个container

(3)networks

相当于docker network create app-net

(4)volumes

相当于-v v1:/var/lib/mysql

(5)image

表示使用哪个镜像，本地build则用build，远端则用image

(6)ports

相当于-p 8080:8080

(7)environment

相当于-e

6.6 docker-compose常见操作

(1)查看版本

docker-compose version

(2)根据yml创建service

docker-compose up
指定yaml：docker-compose  up -f xxx.yaml
后台运行：docker-compose up

(3)查看启动成功的service

docker-compose ps
也可以使用docker ps

(4)查看images

docker-compose images

(5)停止/启动service

docker-compose stop/start

(6)删除service[同时会删除掉network和volume]

docker-compose down

(7)进入到某个service

docker-compose exec redis sh

6.7 scale扩缩容

(1)修改docker-compose.yaml文件，主要是把web的ports去掉，不然会报错

version: '3'
services:
  web:
    build: .
    networks:
      - app-net
  redis:
    image: "redis:alpine"
    networks:
      - app-net
networks:
  app-net:
    driver: bridge

(2)创建service

docker-compose up -d

(3)若要对python容器进行扩缩容

docker-compose up --scale web=5 -d
docker-compose ps
docker-compose logs web

07 Docker Swarm

官网：https://docs.docker.com/swarm/

7.1 Install Swarm

7.1.1 环境准备

(1)根据Vagrantfile创建3台centos机器

[大家可以根据自己实际的情况准备3台centos机器，不一定要使用vagrant+virtualbox]

新建swarm-docker-centos7文件夹，创建Vagrantfile

boxes = [
    {
        :name => "manager-node",
        :eth1 => "192.168.0.11",
        :mem => "1024",
        :cpu => "1"
    },
    {
        :name => "worker01-node",
        :eth1 => "192.168.0.12",
        :mem => "1024",
        :cpu => "1"
    },
    {
        :name => "worker02-node",
        :eth1 => "192.168.0.13",
        :mem => "1024",
        :cpu => "1"
    }
]
Vagrant.configure(2) do |config|
  config.vm.box = "centos/7"
   boxes.each do |opts|
      config.vm.define opts[:name] do |config|
        config.vm.hostname = opts[:name]
        config.vm.provider "vmware_fusion" do |v|
          v.vmx["memsize"] = opts[:mem]
          v.vmx["numvcpus"] = opts[:cpu]
        end
        config.vm.provider "virtualbox" do |v|
          v.customize ["modifyvm", :id, "--memory", opts[:mem]]
          v.customize ["modifyvm", :id, "--cpus", opts[:cpu]]
          v.customize ["modifyvm", :id, "--name", opts[:name]]
        end
        config.vm.network :public_network, ip: opts[:eth1]
      end
  end
end

(2)进入到对应的centos里面，使得root账户能够登陆，从而使用XShell登陆

vagrant ssh manager-node/worker01-node/worker02-node
sudo -i
vi /etc/ssh/sshd_config
修改PasswordAuthentication yes
passwd    修改密码
systemctl restart sshd

(3)在win上ping一下各个主机，看是否能ping通

ping 192.168.0.11/12/13

(4)在每台机器上安装docker engine

小技巧：要想让每个shell窗口一起执行同样的命令”查看—>撰写—>撰写窗口—>全部会话”

7.1.2 搭建Swarm集群

(1)进入manager

提示：manager node也可以作为worker node提供服务

docker swarm init --advertise-addr=192.168.0.11

注意观察日志，拿到worker node加入manager node的信息

docker swarm join --token SWMTKN-1-0a5ph4nehwdm9wzcmlbj2ckqqso38pkd238rprzwcoawabxtdq-arcpra6yzltedpafk3qyvv0y3 192.168.0.11:2377

(2)进入两个worker

docker swarm join --token SWMTKN-1-0a5ph4nehwdm9wzcmlbj2ckqqso38pkd238rprzwcoawabxtdq-arcpra6yzltedpafk3qyvv0y3 192.168.0.11:2377

日志打印

This node joined a swarm as a worker.

(3)进入到manager node查看集群状态

docker node ls

(4)node类型的转换

可以将worker提升成manager，从而保证manager的高可用

docker node promote worker01-node
docker node promote worker02-node
#降级可以用demote
docker node demote worker01-node

7.1.3 在线的

http://labs.play-with-docker.com

7.2 Swarm基本操作

7.2.1 Service

(1)创建一个tomcat的service

docker service create --name my-tomcat tomcat

(2)查看当前swarm的service

docker service ls

(3)查看service的启动日志

docker service logs my-tomcat

(4)查看service的详情

docker service inspect my-tomcat

(5)查看my-tomcat运行在哪个node上

docker service ps my-tomcat

日志

ID                  NAME                IMAGE               NODE                DESIRED STATE       CURRENT STATE           ERROR               PORTS
u6o4mz4tj396        my-tomcat.1         tomcat:latest       worker01-node       Running             Running 3 minutes ago

(6)水平扩展service

docker service scale my-tomcat=3
docker service ls
docker service ps my-tomcat

日志：可以发现，其他node上都运行了一个my-tomcat的service

[root@manager-node ~]# docker service ps my-tomcat
ID                  NAME                IMAGE               NODE                DESIRED STATE       CURRENT STATE            ERROR               PORTS
u6o4mz4tj396        my-tomcat.1         tomcat:latest       worker01-node       Running             Running 8 minutes ago                        
v505wdu3fxqo        my-tomcat.2         tomcat:latest       manager-node        Running             Running 46 seconds ago                       
wpbsilp62sc0        my-tomcat.3         tomcat:latest       worker02-node       Running             Running 49 seconds ago

此时到worker01-node上：docker ps，可以发现container的name和service名称不一样，这点要知道

CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS              PORTS               NAMES
bc4b9bb097b8        tomcat:latest       "catalina.sh run"   10 minutes ago      Up 10 minutes       8080/tcp            my-tomcat.1.u6o4mz4tj3969a1p3mquagxok

(7)如果某个node上的my-tomcat挂掉了，这时候会自动扩展

[worker01-node]
docker rm -f containerid
[manager-node]
docker service ls
docker service ps my-tomcat

(8)删除service

docker service rm my-tomcat

7.2.2 多机通信overlay网络[3.7的延续]

业务场景：workpress+mysql实现个人博客搭建

https://hub.docker.com/_/wordpress?tab=description

7.2.2.1 传统手动方式实现

7.2.2.1.1 一台centos上，分别创建容器

01-创建mysql容器[创建完成等待一会，注意mysql的版本]
    docker run -d --name mysql -v v1:/var/lib/mysql -e MYSQL_ROOT_PASSWORD=examplepass -e MYSQL_DATABASE=db_wordpress mysql:5.6
02-创建wordpress容器[将wordpress的80端口映射到centos的8080端口]
    docker run -d --name wordpress --link mysql -e WORDPRESS_DB_HOST=mysql:3306 -e WORDPRESS_DB_USER=root -e WORDPRESS_DB_PASSWORD=examplepass -e WORDPRESS_DB_NAME=db_wordpress -p 8080:80 wordpress
03-查看默认bridge的网络，可以发现两个容器都在其中
    docker network inspect bridge
04-访问测试
    win浏览器中输入：ip[centos]:8080，一直下一步

7.2.2.1.2 使用docker compose创建

docker-compose的方式还是在一台机器中，网络这块很清晰

01-创建wordpress-mysql文件夹
    mkdir -p /tmp/wordpress-mysql
    cd /tmp/wordpress-mysql
02-创建docker-compose.yml文件

文件内容

version: '3.1'
services:
  wordpress:
    image: wordpress
    restart: always
    ports:
      - 8080:80
    environment:
      WORDPRESS_DB_HOST: db
      WORDPRESS_DB_USER: exampleuser
      WORDPRESS_DB_PASSWORD: examplepass
      WORDPRESS_DB_NAME: exampledb
    volumes:
      - wordpress:/var/www/html
  db:
    image: mysql:5.7
    restart: always
    environment:
      MYSQL_DATABASE: exampledb
      MYSQL_USER: exampleuser
      MYSQL_PASSWORD: examplepass
      MYSQL_RANDOM_ROOT_PASSWORD: '1'
    volumes:
      - db:/var/lib/mysql
volumes:
  wordpress:
  db:

03-根据docker-compose.yml文件创建service
    docker-compose up -d
04-访问测试
    win10浏览器ip[centos]:8080，一直下一步
05-值得关注的点是网络
    docker network ls
    docker network inspect wordpress-mysql_default

7.2.2.2 Swarm中实现

还是wordpress+mysql的案例，在docker swarm集群中怎么玩呢？

(1)创建一个overlay网络，用于docker swarm中多机通信

【manager-node】
docker network create -d overlay my-overlay-net
docker network ls[此时worker node查看不到]

(2)创建mysql的service

【manager-node】
01-创建service
docker service create --name mysql --mount type=volume,source=v1,destination=/var/lib/mysql --env MYSQL_ROOT_PASSWORD=examplepass --env MYSQL_DATABASE=db_wordpress --network my-overlay-net mysql:5.6
02-查看service
    docker service ls
    docker service ps mysql

(3)创建wordpress的service

01-创建service  [注意之所以下面可以通过mysql名字访问，也是因为有DNS解析]
docker service create --name wordpress --env WORDPRESS_DB_USER=root --env WORDPRESS_DB_PASSWORD=examplepass --env WORDPRESS_DB_HOST=mysql:3306 --env WORDPRESS_DB_NAME=db_wordpress -p 8080:80 --network my-overlay-net wordpress
02-查看service
    docker service ls
    docker service ps mysql
03-此时mysql和wordpress的service运行在哪个node上，这时候就能看到my-overlay-net的网络

(4)测试

win浏览器访问ip[manager/worker01/worker02]:8080都能访问成功

(5)查看my-overlay-net

docker network inspect my-overlay-net

(6)为什么没有用etcd？docker swarm中有自己的分布式存储机制

7.3 Routing Mesh

7.3.1 Ingress

通过前面的案例我们发现，部署一个wordpress的service，映射到主机的8080端口，这时候通过swarm集群中的任意主机ip:8080都能成功访问，这是因为什么？

把问题简化：docker service create —name tomcat -p 8080:8080 —network my-overlay-net tomcat

(1)记得使用一个自定义的overlay类型的网络

--network my-overlay-net

(2)查看service情况

docker service ls
docker service ps tomcat

(3)访问3台机器的ip:8080测试

发现都能够访问到tomcat的欢迎页

7.4.2 Internal

之前在实战wordpress+mysql的时候，发现wordpress中可以直接通过mysql名称访问

这样可以说明两点，第一是其中一定有dns解析，第二是两个service的ip是能够ping通的

思考：不妨再创建一个service，也同样使用上述tomcat的overlay网络，然后来实验

docker service create —name whoami -p 8000:8000 —network my-overlay-net -d jwilder/whoami

(1)查看whoami的情况

docker service ps whoami

(2)在各自容器中互相ping一下彼此，也就是容器间的通信

#tomcat容器中ping whoami
docker exec -it 9d7d4c2b1b80 ping whoami
64 bytes from bogon (10.0.0.8): icmp_seq=1 ttl=64 time=0.050 ms
64 bytes from bogon (10.0.0.8): icmp_seq=2 ttl=64 time=0.080 ms
#whoami容器中ping tomcat
docker exec -it 5c4fe39e7f60 ping tomcat
64 bytes from bogon (10.0.0.18): icmp_seq=1 ttl=64 time=0.050 ms
64 bytes from bogon (10.0.0.18): icmp_seq=2 ttl=64 time=0.080 ms

(3)将whoami进行扩容

docker service scale whoami=3
docker service ps whoami     #manager,worker01,worker02

(4)此时再ping whoami service，并且访问whoami服务

#ping
docker exec -it 9d7d4c2b1b80 ping whoami
64 bytes from bogon (10.0.0.8): icmp_seq=1 ttl=64 time=0.055 ms
64 bytes from bogon (10.0.0.8): icmp_seq=2 ttl=64 time=0.084 ms
#访问
docker exec -it 9d7d4c2b1b80 curl whoami:8000  [多访问几次]
I'm 09f4158c81ae
I'm aebc574dc990
I'm 7755bc7da921

小结：通过上述的实验可以发现什么？whoami服务对其他服务暴露的ip是不变的，但是通过whoami名称访问8000端口，确实访问到的是不同的service，就说明访问其实是像下面这张图。

也就是说whoami service对其他服务提供了一个统一的VIP入口，别的服务访问时会做负载均衡。

7.5 Stack

docker stack deploy：https://docs.docker.com/engine/reference/commandline/stack_deploy/

compose-file：https://docs.docker.com/compose/compose-file/

有没有发现上述部署service很麻烦？要是能够类似于docker-compose.yml文件那种方式一起管理该多少？这就要涉及到docker swarm中的Stack，我们直接通过前面的wordpress+mysql案例看看怎么使用咯。

(1)新建service.yml文件

version: '3'
services:
  wordpress:
    image: wordpress
    ports:
      - 8080:80
    environment:
      WORDPRESS_DB_HOST: db
      WORDPRESS_DB_USER: exampleuser
      WORDPRESS_DB_PASSWORD: examplepass
      WORDPRESS_DB_NAME: exampledb
    networks:
      - ol-net
    volumes:
      - wordpress:/var/www/html
    deploy:
      mode: replicated
      replicas: 3
      restart_policy:
        condition: on-failure
        delay: 5s
        max_attempts: 3
      update_config:
        parallelism: 1
        delay: 10s
  db:
    image: mysql:5.7
    environment:
      MYSQL_DATABASE: exampledb
      MYSQL_USER: exampleuser
      MYSQL_PASSWORD: examplepass
      MYSQL_RANDOM_ROOT_PASSWORD: '1'
    volumes:
      - db:/var/lib/mysql
    networks:
      - ol-net
    deploy:
      mode: global
      placement:
        constraints:
          - node.role == manager
volumes:
  wordpress:
  db:
networks:
  ol-net:
    driver: overlay

(2)根据service.yml创建service

docker statck deploy -c service.yml my-service

(3)常见操作

01-查看stack具体信息
    docker stack ls
    NAME                SERVICES            ORCHESTRATOR
    my-service          2                   Swarm
02-查看具体的service
    docker stack services my-service
ID                  NAME                   MODE                REPLICAS            IMAGE               PORTS
icraimlesu61        my-service_db          global              1/1                 mysql:5.7           
iud2g140za5c        my-service_wordpress   replicated          3/3                 wordpress:latest    *:8080->80/tcp
03-查看某个service
    docker service inspect my-service-db
"Endpoint": {
            "Spec": {
                "Mode": "vip"
            },
            "VirtualIPs": [
                {
                    "NetworkID": "kz1reu3yxxpwp1lvnrraw0uq6",
                    "Addr": "10.0.1.5/24"
                }
            ]
        }

(4)访问测试

win浏览器ip[manager,worker01,worker02]:8080

Java docker

03 Docker Compose