Fork me on GitHub 第 3 頁 | Jeff Yang

Docker-compose 2

在 [docker-compose 1] 已經完成安裝compose及執行一個container

現在來測試一次跑多組containers

首先,編譯第一個container所需執行的程式 [Connect to mysql from golang]

更改 main()

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func main() { 
  ip := "10.62.8.175:3306"
  dbName := "test"
  dbString = "root:123456@tcp(" + ip + ")/" + dbName
  tableName := "jeff" 
  runtime.GOMAXPROCS(runtime.NumCPU())
  var dbs DBStruct
  dbs.dbOpen()
  dbs.dbCreate(tableName)
  dbs.dbInsert(tableName)
  dbs.dbClose()
  fmt.Println("===> ",time.Now().Format("20060102150405"))
 //getchar()...防止程式執行完後直接跳出
  reader := bufio.NewReader(os.Stdin)
  reader.ReadString('\n')
}


go build -o goSql goSql.go

再來,編譯第二個container所需執行的程式

更改

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func main() {
  ...
  tableName := "jeff_2"
  ...
}


go build -o goSql_2 goSql.go

更改 docker-compose.yml


build:
 container_name: jeff
 image: centos
 ports: 
   - 9080:9080
 volumes:
   - /home/jeff/code/:/home/code
 restart: always 
 stdin_open: true
 tty: true
 command: bash -c "/home/code/goSql"
build_2:
 container_name: jeff_2
 image: centos
 ports: 
   - 9081:9080
 volumes:
   - /home/jeff/code/:/home/code
 restart: always 
 stdin_open: true
 tty: true
 command: bash -c "/home/code/goSql_2"

執行

docker-compose up -d

Check…

docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
80ac6694738f centos “bash -c /home/code/g" About a minute ago Up 58 seconds 0.0.0.0:9081->9080/tcp jeff_2
a6cb9b81c8e6 centos “bash -c /home/code/g" 4 minutes ago Up 57 seconds 0.0.0.0:9080->9080/tcp jeff

再確認兩筆資料表有寫入資料庫

Docker-compose 1

欲控制多組containers,可以使用現有manage multi-processes軟體如:Supervisor…等
但也許會出現一些問題 http://stackoverflow.com/questions/30034813/best-way-to-manage-docker-containers-with-supervisord

Docker官方提供Compose來執行控制多組containers

https://github.com/docker/compose/

Compose is a tool for defining and running multi-container Docker applications.

安裝…

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$ wget https://bootstrap.pypa.io/ez_setup.py -O - | sudo python
$ sudo easy_install pip
$ sudo pip install -U docker-compose

docker run 轉成 docker-compose yaml 語法…

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# docker run -itd --name jeff --restart=always -p 9080:9080  -v /home/jeff/code/:/home/code centos

# docker-compose.yml
build:   
    container_name: jeff    
    image: centos    
    ports:
        - 9080:9080    
    volumes:        
        - /home/jeff/code/:/home/code    
    restart: always          
    stdin_open: true    
    tty: true

同一目錄下執行…


docker-compose up -d

Check…


docker inspect jeff

Docker 網路連線

CentOS7 下安裝 docker

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$sudo yum install docker
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$sudo service docker start
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$sudo chkconfig docker on

安裝完成後，執行以下指令

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$docker run -it --name jeff -p 9080:9080 -v /home/jeff/code/:/home/code centos /bin/bash

-v /home/jeff/code/:/home/code 掛載Host主機下目錄

一些問題

  • 當進入container掛載目錄後，執行ls發生錯誤

    [root@a52a9c808ba5 code]# ls: cannot open directory .: Permission denied

    解法:
    在Host掛載目錄下執行

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    $chcon -Rt svirt_sandbox_file_t ./code/

  • 容器要想存取外部網路，需要host支援forward

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    $sysctl net.ipv4.ip_forward
    net.ipv4.ip_forward = 1

    如果為 0，說明沒有開啟轉發，則需要手動打開。

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    $sysctl -w net.ipv4.ip_forward=1
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    $service docker restart

  • 進入container後ping外部ip確認是否成功連線

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    [root@a52a9c808ba5 /]# ping 10.62.8.175
    PING 10.62.8.175 (10.62.8.175) 56(84) bytes of data.
    64 bytes from 10.62.8.175: icmp_seq=7 ttl=127 time=1.01 ms

參考:

[1] https://github.com/philipz/docker_practice

[2] http://blog.scottlowe.org/2013/09/04/introducing-linux-network-namespaces/

[3] http://www.infoq.com/cn/articles/docker-network-and-pipework-open-source-explanation-practice#rd

Connect to mysql from golang

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package main
 
import (
  "database/sql"
  "fmt"
  "runtime"
  _ "github.com/go-sql-driver/mysql"
  "time"
)
 
type DBStruct struct {
  db *sql.DB
}
 
var dbString string
 
func (dbs *DBStruct) dbOpen() (err error) { 
  dbs.db, err = sql.Open("mysql", dbString)
  if err != nil {
    fmt.Println("ERROR dbOpen")
  } 
  return err
}
 
func (dbs *DBStruct) dbClose() (err error) { 
  err = dbs.db.Ping()
  if err != nil {
    fmt.Println(err)
    return err
  }
  defer dbs.db.Close() 
  return err
}
 
func (dbs *DBStruct) dbCreate(tableName string) (err error) { 
  err = nil 
  err = dbs.db.Ping()
  if err != nil {
    fmt.Println(err)
    return err
  } 
  c0 := fmt.Sprintf("CREATE TABLE IF NOT EXISTS %s", tableName)
  c1 := fmt.Sprintf("%s ( id INT AUTO_INCREMENT PRIMARY KEY, ", c0)
  c2 := fmt.Sprintf("%s LastUptTime TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP) ", c1) 
  if _, err = dbs.db.Exec(c2); err != nil {
    fmt.Println(err)
    return err
  } 
  return err
}
 
func (dbs *DBStruct) dbInsert(tableName string) (err error) { 
  err = dbs.db.Ping()
  if err != nil {
    fmt.Println(err)
    return err
  } 
  t := time.Now() 
  var INSERT string 
  INSERT = fmt.Sprintf("INSERT INTO %s (LastUptTime) VALUES( '%s') ", tableName, t.Format("20060102150405")) 
  if _, err = dbs.db.Exec(INSERT); err != nil {
    fmt.Println(err)
    return err
  } 
  return err
}
 
func main() { 
  ip := "10.62.8.175:3306"
  dbName := "test"
  dbString = "root:123456@tcp(" + ip + ")/" + dbName
  tableName := "jeff" 
  runtime.GOMAXPROCS(runtime.NumCPU())
  var dbs DBStruct
  dbs.dbOpen() 
  dbs.dbCreate(tableName)   
  dbs.dbInsert(tableName) 
  dbs.dbClose() 
}