Swarm背景

Swarm是什么

Swarm 特点

• 对外以Docker API接口呈现，这样带来的好处是，如果现有系统使用Docker Engine，则可以平滑将Docker Engine切到Swarm上，无需改动现有系统。
• Swarm对用户来说，之前使用Docker的经验可以继承过来。非常容易上手，学习成本和二次开发成本都比较低。同时Swarm本身专注于Docker集群管理，非常轻量，占用资源也非常少。 *“Batteries included but swappable”，简单说，就是插件化机制，Swarm中的各个模块都抽象出了API，可以根据自己一些特点进行定制实现。
• Swarm自身对Docker命令参数支持的比较完善，Swarm目前与Docker是同步发布的。Docker的新功能，都会第一时间在Swarm中体现。

正题，假如设置了--endpoint-mode dnsrr，如何对外呢？

  # add current user to docker group so that it can execute docker commands

  sudo usermod -aG docker $USER

  yum -y install bash-completion

  docker swarm init --advertise-addr 127.0.0.1

  # create an overlay network

  docker network create --driver overlay swarm-net

  我们创建了名字叫 swarm-net network环境，接着我们创建nginx转发路由服务：

  docker service create \
--replicas 1 \
--name proxy_docker \
--network swarm-net \
--publish published=8088,target=8088 \
--publish published=50070,target=50070 \

centos7.3:latest /usr/sbin/init /bin/bash

我们来看看官方的说明：

Use the --publish flag to publish a port when you create a service. target is used to specify the port inside the container, and published is used to specify the port to bind on the routing mesh. If you leave off the published port, a random high-numbered port is bound for each service task. You need to inspect the task to determine the port.

$ docker service create \
  --name <SERVICE-NAME> \
  --publish published=<PUBLISHED-PORT>,target=<CONTAINER-PORT> \
  <IMAGE>

Note: The older form of this syntax is a colon-separated string, where the published port is first and the target port is second, such as -p 8088:8088. The new syntax is preferred because it is easier to read and allows more flexibility.

The <PUBLISHED-PORT> is the port where the swarm makes the service available. If you omit it, a random high-numbered port is bound. The <CONTAINER-PORT> is the port where the container listens. This parameter is required.

效果跟-p参数是一样的，接着我们进去服务器里边，egg:

通过ps参数我们知道了我们刚刚创建的proxy_docker容器信息（329a7d31bcff），现在正是进去

docker exec -it 329a7d31bcff /bin/sh

安装nginx服务

1、添加源

nginx 默认允许在daemon模式下，在执行docker run -d nginx /usr/bin/nginx 的时候会自动退出，

在nginx的nginx.conf文件最上面一行加入。

vi /etc/nginx/nginx.conf

添加转发配置，在/etc/nginx/conf.d/目录下添加:

upstream hadoop {
    server hadoop-master:50070;
}
server {
    listen       50070;
    server_name  localhost;

    #charset koi8-r;
    #access_log  /var/log/nginx/host.access.log  main;

    location / {
        proxy_pass   http://hadoop;
        index  index.html index.htm;
    }

    #error_page  404              /404.html;

    # redirect server error pages to the static page /50x.html
    #
    error_page   500 502 503 504  /50x.html;
    location = /50x.html {
        root   /usr/share/nginx/html;
    }

    # proxy the PHP scripts to Apache listening on 127.0.0.1:80
    #
    #location ~ \.php$ {
    #    proxy_pass   http://127.0.0.1;
    #}

    # pass the PHP scripts to FastCGI server listening on 127.0.0.1:9000
    #
    #location ~ \.php$ {
    #    root           html;
    #    fastcgi_pass   127.0.0.1:9000;
    #    fastcgi_index  index.php;
    #    fastcgi_param  SCRIPT_FILENAME  /scripts$fastcgi_script_name;
    #    include        fastcgi_params;
    #}

    # deny access to .htaccess files, if Apache's document root
    # concurs with nginx's one
    #
    #location ~ /\.ht {
    #    deny  all;
    #}
}

server {
    listen       8088;
    server_name  localhost;

    #charset koi8-r;
    #access_log  /var/log/nginx/host.access.log  main;

    location / {
        proxy_pass   http://hadoop_hdfs;
        index  index.html index.htm;
    }

    #error_page  404              /404.html;

    # redirect server error pages to the static page /50x.html
    #
    error_page   500 502 503 504  /50x.html;
    location = /50x.html {
        root   /usr/share/nginx/html;
    }

    # proxy the PHP scripts to Apache listening on 127.0.0.1:80
    #
    #location ~ \.php$ {
    #    proxy_pass   http://127.0.0.1;
    #}

    # pass the PHP scripts to FastCGI server listening on 127.0.0.1:9000
    #
    #location ~ \.php$ {
    #    root           html;
    #    fastcgi_pass   127.0.0.1:9000;
    #    fastcgi_index  index.php;
    #    fastcgi_param  SCRIPT_FILENAME  /scripts$fastcgi_script_name;
    #    include        fastcgi_params;
    #}

    # deny access to .htaccess files, if Apache's document root
    # concurs with nginx's one
    #
    #location ~ /\.ht {
    #    deny  all;
    #}
}

# sysctl net.ipv4.ip_forward

截图：

宿机下执行 netstat -tlnp 发现端口映射有ok了，然后浏览器访问：

都是ok的