1. 引言
上兩節我們通過簡單的demo學習了docker的基本操作。這一節我們來一個進階學習，完成ASP.NET Core + MySql + Nginx的容器化部署。
本文是基於CentOS 7.4環境進行演示，示例專案可以訪問*Docker.NetCore.MySql*進行下載。
2. Hello MySQL
同樣我們還是以循序漸進的方式來展開。首先來基於Docker來試玩一下MySQL。
2.1. 建立MySql例項
//拉取mysql映象
docker pull mysql
$ docker images$
REPOSITORY TAG IMAGE ID CREATED SIZE
docker.io/mysql latest 7d83a47ab2d2 13 days ago 408.2 MB
//建立一個mysql例項
$ docker run --name hello.mysql -e MYSQL_ROOT_PASSWORD=123456 -d mysql
$ docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
e21bbd84e0b5 mysql "docker-entrypoint.sh" 3 minutes ago Up 3 minutes 3306/tcp hello.mysql
複製程式碼下面我們直接在容器中連線到我們剛剛建立的mysql資料庫：
$ docker exec -it hello.mysql \
> mysql -uroot -p123456
mysql: [Warning] Using a password on the command line interface can be insecure.
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 8
Server version: 5.7.20 MySQL Community Server (GPL)
Copyright (c) 2000, 2017, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
| sys |
+--------------------+
4 rows in set (0.00 sec)
複製程式碼2.2. 掛載資料卷
上面建立的mysql例項其資料都在容器內部儲存，這樣就暴露了一個問題，如果容器銷燬，那麼對應的資料庫資料就會丟失。那如何持久化儲存容器內資料呢？我們可以通過掛載資料卷的方式來解決這一問題。
//建立資料卷
$ docker volume create --name hello.db
hello.db
//檢視資料卷資訊
$ docker volume inspect hello.db
[
{
"Name": "hello.db",
"Driver": "local",
"Mountpoint": "/var/lib/docker/volumes/hello.db/_data",
"Labels": {},
"Scope": "local"
}
]
// 掛載資料卷啟動MySql例項
$ docker run --name hello.mysql \
> -v hello.db:/var/lib/mysql \
> -e MYSQL_ROOT_PASSWORD=123456 -d mysql
複製程式碼上面是使用使用了docker volume create命令建立了一個資料卷，當然我們也可以自行掛載某個目錄作為資料卷。
3. 準備.NET Core+EFCore+MySql專案
為了演示方便，我準備了一個ASP.NET Core+EFCore+MySql的示例專案。其結構如下所示：
Product實體，並通過ProductsController暴露WebApi介面。核心程式碼如下：
Product實體類：
public class Product
{
public int ProductId { get; set; }
public string Name { get; set; }
public decimal Price { get; set; }
public int StockQty { get; set; }
}
複製程式碼DbContext類：
public class MySqlDbContext : DbContext
{
public MySqlDbContext (DbContextOptions<MySqlDbContext> options)
: base(options)
{
}
public DbSet<Product> Products { get; set; }
}
複製程式碼資料庫初始化類：
public class DbInitializer
{
public static void Initialize(MySqlDbContext context)
{
context.Database.EnsureCreated();
if (context.Products.Any())
{
return;
}
var products = new Product[]
{
new Product{Name="iphone 6",Price=5000,StockQty=10 },
new Product{Name="iphone 7",Price=6000,StockQty=10 },
new Product{Name="iphone 7 plus",Price=7000,StockQty=10 },
new Product{Name="iphone x",Price=8000,StockQty=10 }
};
context.Products.AddRange(products);
context.SaveChanges();
}
}
複製程式碼該資料庫初始化類會在專案啟動時執行。詳細程式碼可參考**Docker.NetCore.MySql**。
4. 基於示例專案進行實操演練
4.1 安裝Git並Clone示例專案
$ yum install git
$ git --version
git version 1.8.3.1
$ cd ~/demo
$ git clone https://github.com/yanshengjie/Docker.NetCore.MySql.git
Cloning into 'Docker.NetCore.MySql'...
remote: Counting objects: 155, done.
remote: Compressing objects: 100% (125/125), done.
remote: Total 155 (delta 42), reused 123 (delta 25), pack-reused 0
Receiving objects: 100% (155/155), 534.30 KiB | 333.00 KiB/s, done.
Resolving deltas: 100% (42/42), done.
複製程式碼4.2. 構建映象
細心的你會發現，專案中已經定義了Dockerfile，所以我們可以直接使用docker build構建映象。
# cd Docker.NetCore.MySql
[root@iZ288a3qazlZ Docker.NetCore.MySql]# ls
appsettings.Development.json docker-compose.yml Program.cs Views
appsettings.json Dockerfile proxy.conf wwwroot
bundleconfig.json Docker.NetCore.MySql.csproj README.md
Controllers LICENSE ScaffoldingReadMe.txt
Data Models Startup.cs
//構建映象
# docker build -t docker.netcore.mysql .
Sending build context to Docker daemon 3.045 MB
Step 1 : FROM microsoft/dotnet:latest
---> 7d4dc5c258eb
Step 2 : WORKDIR /app
---> Using cache
---> 98d48a4e278c
Step 3 : COPY . /app
---> 6b1bf8bb5261
Removing intermediate container b86460477977
Step 4 : RUN dotnet restore
---> Running in 4e0a46f762bb
Restoring packages for /app/Docker.NetCore.MySql.csproj...
Installing Microsoft.CodeAnalysis.Razor 2.0.0.
.....
Restore completed in 216.83 ms for /app/Docker.NetCore.MySql.csproj.
---> 4df70c77916e
Removing intermediate container 4e0a46f762bb
Step 5 : EXPOSE 5000
---> Running in 11b421b3bd3e
---> 3506253060fe
Removing intermediate container 11b421b3bd3e
Step 6 : ENV ASPNETCORE_URLS http://*:5000
---> Running in 201aabbab72c
---> 7f29963a8d96
Removing intermediate container 201aabbab72c
Step 7 : ENTRYPOINT dotnet run
---> Running in c79f73cba162
---> 9d1fb6ee46cb
Removing intermediate container c79f73cba162
Successfully built 9d1fb6ee46cb
[root@iZ288a3qazlZ Docker.NetCore.MySql]# docker images docker.netcore.mysql
REPOSITORY TAG IMAGE ID CREATED SIZE
docker.netcore.mysql latest 9d1fb6ee46cb 13 seconds ago 1.756 GB
複製程式碼4.3. 啟動映象並連線到指定資料庫
docker提供了--link引數用於在容器之間建立連線。下面我們例項化建立的映象docker.netcore.mysql並命名容器名為hello.netcore.mysql，並使用--link引數與我們文章開頭建立的hello.mysql容器建立連線。
# docker run --name hello.netcore.mysql --link hello.mysql:db -d -p 5000:5000
docker.netcore.mysql
複製程式碼這裡需要特別注意一下
--link=hello.mysql:db，這個引數就是告訴Docker容器需要使用hello.mysql容器，並將其別名命名為db，這樣在hello.netcore.mysql這個容器中就可以使用db來作為提供mysql資料庫服務的伺服器。這也就是為什麼我們.NET Core專案中連線字串設定為server=db;的原因。"ConnectionStrings": { "MySql": "server=db;database=MySqlDbContext;uid=root;pwd=123456;" }
//檢視執行中容器列表
# docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
5cbfd27ebe2a docker.netcore.mysql "dotnet run" 2 minutes ago Up 2 minutes 0.0.0.0:5000->5000/tcp hello.netcore.mysql
4dfa4159b669 mysql "docker-entrypoint.sh" About an hour ago Up About an hour 3306/tcp hello.mysql
//訪問api/products
[root@iZ288a3qazlZ Docker.NetCore.MySql]# curl http://localhost:5000/api/products
[{"productId":1,"name":"iphone 6","price":5000.0000000000000000000000000,"stockQty":10},{"productId":2,"name":"iphone 7","price":6000.0000000000000000000000000,"stockQty":10},{"productId":3,"name":"iphone 7 plus","price":7000.0000000000000000000000000,"stockQty":10},{"productId":4,"name":"iphone x","price":8000.000000000000000000000000,"stockQty":10}]
複製程式碼從上圖可知，我們完成了.NET Core與MySql的連線。
5. ASP.NET Core + MySql + Nginx
結合上一篇文章.NET Core容器化之多容器應用部署@Docker-Compose，我們來使用docker-compose完成asp.net core + mysql + nginx的多容器部署。
5.1. 定義 docker-compose.yml
version: '2'
services:
db:
container_name: hello.db
environment:
MYSQL_ROOT_PASSWORD: 123456
volumes:
- ./mysql:/var/lib/mysql
web:
container_name: hello.web
build: .
depends_on:
- db
links:
- db
reverse-proxy:
container_name: hello.proxy
image: nginx
depends_on:
- web
ports:
- "9090:8080"
volumes:
- ./proxy.conf:/etc/nginx/conf.d/default.conf
複製程式碼其中定義了三個服務：
- db：使用mysql映象，並掛載當前專案下的mysql資料夾來持久化儲存。
- web：基於當前專案構建的容器服務，依賴於db服務。
- reverse-proxy：使用nginx定義反向代理服務，其中掛載了當前專案下的proxy.conf檔案作為反向代理配置檔案。其中proxy.conf的配置如下（注意proxy_pass指定的url為http://web:5000)：
server {
listen 8080;
location / {
proxy_pass http://web:5000;
}
}
複製程式碼5.2. 啟動Compose
在啟動Compose之前，建議清空上面建立的容器。也可以使用docker rm $(docker ps -qa)清除所有容器。
//啟動compose
[root@iZ288a3qazlZ Docker.NetCore.MySql]# docker-compose up -d
Creating network "dockernetcoremysql_default" with the default driver
Building web
Step 1 : FROM microsoft/dotnet:latest
---> 7d4dc5c258eb
Step 2 : WORKDIR /app
---> Using cache
---> 98d48a4e278c
Step 3 : COPY . /app
---> d41b32323c0f
Removing intermediate container 1259f5fb82bc
Step 4 : RUN dotnet restore
---> Running in d482e355de77
Restoring packages for /app/Docker.NetCore.MySql.csproj...
Installing Microsoft.CodeAnalysis.Razor 2.0.0.
.....
Restore completed in 216.83 ms for /app/Docker.NetCore.MySql.csproj.
---> a0658008f161
Removing intermediate container d482e355de77
Step 5 : EXPOSE 5000
---> Running in dc6eeb29fd5e
---> a419314ece08
Removing intermediate container dc6eeb29fd5e
Step 6 : ENV ASPNETCORE_URLS http://*:5000
---> Running in c1d1474b14a0
---> 9cc13c549042
Removing intermediate container c1d1474b14a0
Step 7 : ENTRYPOINT dotnet run
---> Running in efdf0e857a84
---> 830ac11428cf
Removing intermediate container efdf0e857a84
Successfully built 830ac11428cf
Creating hello.db ... done
Creating hello.web ... done
Creating hello.proxy ... done
Creating hello.web ...
Creating hello.proxy ...
[root@iZ288a3qazlZ Docker.NetCore.MySql]# docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
6253bf85682e nginx "nginx -g 'daemon off" 33 seconds ago Up 28 seconds 80/tcp, 0.0.0.0:9090->8080/tcp hello.proxy
ea553a9e22f2 dockernetcoremysql_web "dotnet run" 37 seconds ago Up 32 seconds 5000/tcp hello.web
a1f5aa981bfb mysql "docker-entrypoint.sh" 38 seconds ago Up 36 seconds 3306/tcp hello.db
[root@iZ288a3qazlZ Docker.NetCore.MySql]# docker-compose ps
Name Command State Ports
----------------------------------------------------------------------------------
hello.db docker-entrypoint.sh mysqld Up 3306/tcp
hello.proxy nginx -g daemon off; Up 80/tcp, 0.0.0.0:9090->8080/tcp
hello.web dotnet run Up 5000/tcp
[root@iZ288a3qazlZ Docker.NetCore.MySql]# curl http://localhost:9090/api/products
[{"productId":1,"name":"iphone 6","price":5000.0000000000000000000000000,"stockQty":10},{"productId":2,"name":"iphone 7","price":6000.0000000000000000000000000,"stockQty":10},{"productId":3,"name":"iphone 7 plus","price":7000.0000000000000000000000000,"stockQty":10},{"productId":4,"name":"iphone x","price":8000.000000000000000000000000,"stockQty":10}]
複製程式碼上面的執行結果顯示，我們已經成功完成了ASP.NET Core+MySql+Nginx的多容器應用部署。通過瀏覽器訪問http:<ipaddress>:9090/api/products即可訪問我們暴露的api。
5.3. 資料庫驗證
我們來驗證一下資料庫是否成功建立：
[root@iZ288a3qazlZ Docker.NetCore.MySql]# ls mysql
auto.cnf client-key.pem ib_logfile0 performance_schema server-key.pem
ca-key.pem MySqlDbContext ib_logfile1 private_key.pem sys
ca.pem ib_buffer_pool ibtmp1 public_key.pem
client-cert.pem ibdata1 mysql server-cert.pem
[root@iZ288a3qazlZ Docker.NetCore.MySql]# docker exec -it hello.db mysql -uroot -p123456
mysql: [Warning] Using a password on the command line interface can be insecure.
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 8
Server version: 5.7.20 MySQL Community Server (GPL)
Copyright (c) 2000, 2017, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> show databases;
+-----------------------+
| Database |
+-----------------------+
| information_schema |
| MySqlDbContext |
| mysql |
| performance_schema |
| sys |
+-----------------------+
5 rows in set (0.00 sec)
mysql> use MySqlDbContext;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A
Database changed
mysql> show tables;
+---------------------------------+
| Tables_in_MySqlDbContext |
+---------------------------------+
| Products |
+---------------------------------+
1 row in set (0.00 sec)
mysql> select * from Products;
+-----------+---------------+-------------------------------------+----------+
| ProductId | Name | Price | StockQty |
+-----------+---------------+-------------------------------------+----------+
| 1 | iphone 6 | 5000.000000000000000000000000000000 | 10 |
| 2 | iphone 7 | 6000.000000000000000000000000000000 | 10 |
| 3 | iphone 7 plus | 7000.000000000000000000000000000000 | 10 |
| 4 | iphone x | 8000.000000000000000000000000000000 | 10 |
+-----------+---------------+-------------------------------------+----------+
4 rows in set (0.00 sec)
複製程式碼從上面的執行結果可知，我們成功將專案資料夾下的mysql資料夾掛載到容器內部進行資料持久化。
6. 最後
本文通過先介紹如何基於Docker例項化MySQL容器，再介紹如何通過掛載資料捲來持久化MySQL資料，以及如何使用--Link引數進行容器之間的連線，完成了.NET Core連線MySQL資料庫。 最後，使用Docker-Compose綜合ASP.NET Core+MySQL+Nginx完成了容器化部署。
下一節我們來介紹下如何使用Docker-Swarm進行叢集部署。