8天入门docker系列 —— 第五天 使用aspnetcore小案例熟悉容器互联和docker-compose一键部署

 

　　这一篇继续完善webnotebook，若是你读过上一篇的内容，你应该知道怎么去挂载webnotebook日志和容器的远程访问，可是这些还远不够，webnotebook

总要和一些数据库打交道吧，好比说mysql，mongodb，redis，一般状况下这些存储设备要么是以容器的方式承载，要么是由DBA在非容器环境下统一管理。

 

一：webnotebook链接容器redis

       咱们作一个小案例，把网站的全部PV记录到redis中，webnotebook前端显示当前你是 xxx 位用户，案例不重要，重要的是怎么去实现容器互联。

 

      在docker hub 上去找redis的官方镜像，具体redis该如何合理配置这里我就无论了，用最简单的一条docker run 跑起来再说。

[root@localhost data]# docker run --name some-redis -d redis
Unable to find image 'redis:latest' locally
latest: Pulling from library/redis
6ae821421a7d: Pull complete 
e3717477b42d: Pull complete 
8e70bf6cc2e6: Pull complete 
0f84ab76ce60: Pull complete 
0903bdecada2: Pull complete 
492876061fbd: Pull complete 
Digest: sha256:dd5b84ce536dffdcab79024f4df5485d010affa09e6c399b215e199a0dca38c4
Status: Downloaded newer image for redis:latest
ed07890700a5cdb7d737a196c28009a9d1b08de35f55d51f53c80e6cfe6ba199
[root@localhost data]# 
[root@localhost data]# 
[root@localhost data]# docker ps
CONTAINER ID        IMAGE               COMMAND                  CREATED              STATUS              PORTS               NAMES
ed07890700a5        redis               "docker-entrypoint.s…"   About a minute ago   Up About a minute   6379/tcp            some-redis

    

    接下来安装 StackExchange.Redis，在Index这个Action中将当前的访问做为一个PV记录到redis中，不过下面的代码要注意一点的就是，为了去访问redis，

这里我采用了redis.webnotebook.com 去映射到redis容器的ip，映射关系能够在建立容器的时候自动追加到 /etc/hosts 中，每一次访问都执行一次Increment自

增操做。

   public class HomeController : Controller
    {
        public static Logger logger = LogManager.GetLogger("SimpleDemo");
        public static ConnectionMultiplexer redis = ConnectionMultiplexer.Connect("redis.webnotebook.com:6379");

        /// <summary>
        /// 读取mongodb数据数据
        /// </summary>
        /// <returns></returns>
        public IActionResult Index()
        {
            var db = redis.GetDatabase();

            var num = db.StringIncrement("count");

            ViewData["num"] = num;

            return View();
        }
    }

   

     在UI上，展现下你当前是多少位访客，就是这样。

<div class="text-center">
    <h1 class="display-4">您是当前 @ViewData["num"]  位访客</h1>
    <p>Learn about <a href="https://docs.microsoft.com/aspnet/core">building Web apps with ASP.NET Core</a>.</p>
</div>

     

     而后你就能够docker build，完了以后docker run时经过 --link  some-redis:redis.webnotebook.com  去指定一下就行了，some-redis是redis容器的名字，

redis.webnotebook.com 是这个some-redis别名，这样就方便的实现了 redis.webnotebook.com和容器ip的映射关系。

[root@localhost publish]# docker run -d --name webnotebook -p 8080:8080 --link some-redis:redis.webnotebook.com huangxincheng/webnotebook:v1
b931e040de26c4bfc0b49cbc8e626cdcb30ad9bdff523f623c0a2d6c50899a81
[root@localhost publish]# 
[root@localhost publish]# 
[root@localhost publish]# docker ps
CONTAINER ID        IMAGE                          COMMAND                  CREATED             STATUS              PORTS                    NAMES
b931e040de26        huangxincheng/webnotebook:v1   "dotnet WebNotebook.…"   2 seconds ago       Up 2 seconds        0.0.0.0:8080->8080/tcp   webnotebook
ed07890700a5        redis                          "docker-entrypoint.s…"   27 minutes ago      Up 27 minutes       6379/tcp                 some-redis

       有些人可能就好奇了，到底webnotebook容器内的/etc/hosts真的修改了吗？ 接下来你能够经过 docker exec 到webnotebook容器去看一下就好啦，

从下面标红的地方能够看到，172.17.0.2 已经和 xxx.com 作了映射。

[root@localhost publish]# docker exec -it webnotebook /bin/bash
root@b931e040de26:/data# cat /etc/hosts
127.0.0.1    localhost
::1    localhost ip6-localhost ip6-loopback
fe00::0    ip6-localnet
ff00::0    ip6-mcastprefix
ff02::1    ip6-allnodes
ff02::2    ip6-allrouters
172.17.0.2    redis.webnotebook.com ed07890700a5 some-redis
172.17.0.3    b931e040de26
root@b931e040de26:/data# 

 

     回到文章开头的问题，若是redis是在远程宿主机上部署的，那个人webnotebook容器该怎么访问呢？你可能会说，直接经过ip访问便可，可是为了保持

统一性，我仍是但愿经过redis.webnotebook.com 这个域名进行访问，也就是说怎么去把这个映射关系追加到容器中呢？可使用-- add-host来实现。

[root@localhost publish]#  docker run -d --name webnotebook -p 8080:8080 --add-host redis.webnotebook.com:172.17.0.2 huangxincheng/webnotebook:v1
91e7d9c1b575cc34ae98eebfc437d081b852f450104e2b368f898299852b0f18
[root@localhost publish]# docker exec -it webnotebook /bin/bash
root@91e7d9c1b575:/data# cat /etc/hosts
127.0.0.1    localhost
::1    localhost ip6-localhost ip6-loopback
fe00::0    ip6-localnet
ff00::0    ip6-mcastprefix
ff02::1    ip6-allnodes
ff02::2    ip6-allrouters
172.17.0.2    redis.webnotebook.com
172.17.0.3    91e7d9c1b575
root@91e7d9c1b575:/data# 

   

二：docker-compose 容器编排

      目前咱们仅引入了redis，这样有了两个容器，但随着业务的增长，你可能还须要mysql，ssdb，rabbitmq，nginx等服务，而docker建议的就是一个容器

一个进程，那为了能顺利承载这些服务，你可能须要部署6个容器，若是你仍是按照老一套的方法一个一个的去部署，操做起来就比较乱，有没有一种方式可

以让docker自动帮咱们一键部署好这些容器呢？ 就好像dockerfile那样自动化部署，固然有了，那就是docker-compose 容器编排。

 

1. 安装

    官网地址：https://docs.docker.com/compose/install/#install-compose  而后按照步骤一步一步来就行了，最后经过docker-compose --version 看一下便可。

[root@localhost publish]# sudo curl -L "https://github.com/docker/compose/releases/download/1.23.2/docker-compose-$(uname -s)-$(uname -m)" -o /usr/local/bin/docker-compose
[root@localhost publish]# sudo chmod +x /usr/local/bin/docker-compose
[root@localhost publish]# docker-compose --version
docker-compose version 1.22.0, build f46880fe
[root@localhost publish]#

 

2. 编写docker-compose 

    docker-compose的全部命令都在 https://docs.docker.com/compose/compose-file/  上面找获得，若是有兴趣能够查看一下。

version: '3.0'
services:
  webnotebook:
    container_name: webnotebook
    build: 
      context: .
      dockerfile: ./Dockerfile
    depends_on:
      - redis
    links:
      - "redis:redis.webnotebook.com"
    ports:
      - "8080:8080"
  redis:
   container_name: some-redis
   image: redis

 

   上面的配置看起来不难吧，若是不知道参数的意思，仍是那句话，查看官方文档， 最后你可使用 docker-compose up --build 跑起来，或者使用 -d 参数

进行后台运行。

[root@localhost publish]# docker-compose up --build
Building webnotebook
Step 1/9 : FROM microsoft/dotnet:2.2-aspnetcore-runtime
 ---> dad26d192ae6
Step 2/9 : ENV TZ Asia/Shanghai
 ---> Using cache
 ---> 72535a350c5d
Step 3/9 : LABEL author hxc@qq.com
 ---> Using cache
 ---> d4dcb4ba06aa
Step 4/9 : RUN mkdir /data
 ---> Using cache
 ---> 6bbfc1537e42
Step 5/9 : COPY ./ /data
 ---> Using cache
 ---> 5401b74ec21f
Step 6/9 : WORKDIR /data
 ---> Using cache
 ---> d93e7949b527
Step 7/9 : VOLUME /data/log
 ---> Using cache
 ---> 39c4285c6d6c
Step 8/9 : EXPOSE 8080
 ---> Using cache
 ---> d02932ddfbcc
Step 9/9 : CMD [ "dotnet","WebNotebook.dll" ]
 ---> Using cache
 ---> 0572ceea51a1
Successfully built 0572ceea51a1
Successfully tagged publish_webnotebook:latest
Starting some-redis ... done
Starting webnotebook ... done
Attaching to some-redis, webnotebook
some-redis     | 1:C 22 Feb 2019 09:11:03.160 # oO0OoO0OoO0Oo Redis is starting oO0OoO0OoO0Oo
some-redis     | 1:C 22 Feb 2019 09:11:03.160 # Redis version=5.0.3, bits=64, commit=00000000, modified=0, pid=1, just started
some-redis     | 1:C 22 Feb 2019 09:11:03.160 # Warning: no config file specified, using the default config. In order to specify a config file use redis-server /path/to/redis.conf
some-redis     | 1:M 22 Feb 2019 09:11:03.161 * Running mode=standalone, port=6379.
some-redis     | 1:M 22 Feb 2019 09:11:03.161 # WARNING: The TCP backlog setting of 511 cannot be enforced because /proc/sys/net/core/somaxconn is set to the lower value of 128.
some-redis     | 1:M 22 Feb 2019 09:11:03.161 # Server initialized
some-redis     | 1:M 22 Feb 2019 09:11:03.161 # WARNING overcommit_memory is set to 0! Background save may fail under low memory condition. To fix this issue add 'vm.overcommit_memory = 1' to /etc/sysctl.conf and then reboot or run the command 'sysctl vm.overcommit_memory=1' for this to take effect.
some-redis     | 1:M 22 Feb 2019 09:11:03.161 # WARNING you have Transparent Huge Pages (THP) support enabled in your kernel. This will create latency and memory usage issues with Redis. To fix this issue run the command 'echo never > /sys/kernel/mm/transparent_hugepage/enabled' as root, and add it to your /etc/rc.local in order to retain the setting after a reboot. Redis must be restarted after THP is disabled.
some-redis     | 1:M 22 Feb 2019 09:11:03.161 * Ready to accept connections
webnotebook    | : Microsoft.AspNetCore.DataProtection.KeyManagement.XmlKeyManager[0]
webnotebook    |       User profile is available. Using '/root/.aspnet/DataProtection-Keys' as key repository; keys will not be encrypted at rest.
webnotebook    | Hosting environment: Production
webnotebook    | Content root path: /data
webnotebook    | Now listening on: http://[::]:8080
webnotebook    | Application started. Press Ctrl+C to shut down.

很是简单吧，只要我有一个docker-comose文件就能够实现一键部署，好了，但愿本篇对你有帮助。