摘要：腳本運行函數執行完后，刪除啟動以上是制作鏡像的配置文件。鏡像必須先鏡像，才能鏡像。查看容器狀態進入到容器中查看數據庫只要數據庫文件目錄存在，可以隨意刪除重建，恢復很快。

構建DB Docker鏡像

mysql的代碼文件

[root@Optimus /]# cd docker-training/
[root@Optimus docker-training]# ls
centos7  mysql  php-fpm  README.md  wordpress
[root@Optimus docker-training]# cd mysql/
[root@Optimus mysql]# ls
Dockerfile  mysqld_charset.cnf  scripts
[root@Optimus mysql]# 

dockerfile用于構建DB docker鏡像

[root@Optimus mysql]# vim Dockerfile 

#
# MAINTAINER        Carson,C.J.Zeong 
# DOCKER-VERSION    1.6.2
#
# Dockerizing Mariadb: Dockerfile for building Mariadb images
#
FROM csphere/centos:7.1
MAINTAINER Carson,C.J.Zeong 

ENV DATA_DIR /var/lib/mysql

# Install Mariadb
RUN yum install -y mariadb mariadb-server && 
                                        yum clean all

ADD mysqld_charset.cnf /etc/my.cnf.d/

COPY scripts /scripts
RUN chmod +x /scripts/start

EXPOSE 3306

VOLUME ["/var/lib/mysql"]

ENTRYPOINT ["/scripts/start"]

[FROM csphere/centos:7.1] 構建完成后，具有centos7.1和Mariadb的功能。可以用php-fpm的鏡像進行構建，但升級更新復雜。

[MAINTAINER Carson,C.J.Zeong ]

[ENV DATA_DIR /var/lib/mysql]設置一個DATA_DIR的環境變量，對應的目錄是/var/lib/mysql

[RUN yum install -y mariadb mariadb-server && yum clean all] 安裝了mariadb和mariadb-server

[ADD mysqld_charset.cnf /etc/my.cnf.d/] 添加mysql的字符文件到/etc/my.cnf.d/目錄下

[COPY scripts /scripts] 從本地復制文件scripts到container中的/scripts

[RUN chmod +x /scripts/start] 給start文件加一個執行權限

[EXPOSE 3306] 默認3306端口

[VOLUME ["/var/lib/mysql"]] 通過docker鏡像啟動了docker容器，把docker容器刪除以后，里面所有的數據都會隨著docker container被刪除，但是db container不需要一并把數據庫也刪除，所有需要通過VOLUME把數據庫數據保留下來，container刪除后數據仍然保留。VOLUME通過宿主機的文件目錄去映射container的文件目錄/var/lib/mysql。

[ENTRYPOINT ["/scripts/start"]] 啟動start腳本文件

start腳本

[root@Optimus mysql]# cd scripts/
[root@Optimus scripts]# ls
firstrun  firstrun_maria  start

啟動container時主要執行start腳本，start是一個/bin/bash腳本

#!/bin/bash

set -e

#
# When Startup Container script
#

if [[ -e /scripts/firstrun ]]; then
    # config mariadb
    /scripts/firstrun_maria
    rm /scripts/firstrun
else
    # Cleanup previous mariadb sockets
    if [[ -e ${DATA_DIR}/mysql.sock ]]; then
        rm -f ${DATA_DIR}/mysql.sock
    fi
fi

exec /usr/bin/mysqld_safe

[#!/bin/bash] /bin/bash腳本

[set -e]加了該命令以后，如果第一條命令執行錯誤則直接退出。

[if [[ -e /scripts/firstrun ]]; then] 判斷一下firstrun這個文件在不在。在構建db container的時候，需要在啟動的時候做一些數據庫初始化的工作，為數據庫創建一個數據庫用戶，以及給數據庫用戶創建密碼。因此在啟動時，需要一個邏輯判斷。

[/scripts/firstrun_maria] 如果firstrun存在，就執行firstrun_maria腳本

[rm /scripts/firstrun] 執行完firstrun_maria以后，把firstrun刪掉。因為在第二次啟動的時候不希望再執行類似的操作，直接啟動mariadb即可。

firstrun_Maria腳本

[/scripts/firstrun_maria] 運行firstrun_maria函數

[rm /scripts/firstrun] 執行完后，刪除firstrun

[exec /usr/bin/mysqld_safe] 啟動mysql

以上是制作db鏡像的配置文件。

build db鏡像

docker build -t csphere/mysql:5.5
必須先build centos7鏡像，才能build db鏡像。

查看當前本地docker鏡像

docker images
 
[root@Optimus mysql]# docker images
REPOSITORY          TAG                 IMAGE ID            CREATED             VIRTUAL SIZE
csphere/mysql       5.5                 e147ac2a588e        15 minutes ago      752.7 MB
csphere/php-fpm     5.4                 1b08c94ce801        2 days ago          709.7 MB
csphere/centos      7.1                 fd1f7619e63e        3 days ago          613 MB
centos              centos7.1.1503      879c6d07c60e        6 weeks ago         212.1 MB

構建好docker鏡像，下面啟動mariadb的docker容器

docker run -d -p 3306:3306 --name dbserver csphere/mysql:5.5

查看本地docker容器

[root@Optimus mysql]# docker ps -a

出錯：顯示3306端口被占用

[root@Optimus mysql]# docker run -d -p 3306:3306 --name dbserver csphere/mysql:5.5
e63911262c9490d65be1bc9c1c575f2eebaacc0c3afa3874e0f4cd687b5fc717
Error response from daemon: Cannot start container e63911262c9490d65be1bc9c1c575f2eebaacc0c3afa3874e0f4cd687b5fc717: Error starting userland proxy: listen tcp 0.0.0.0:3306: bind: address already in use
[root@Optimus mysql]# fuser -v -n tcp 3306
                                                                                                                                                                                                                  USER        PID ACCESS COMMAND
3306/tcp:            mysql      2928 F.... mysqld
[root@Optimus mysql]# docker ps -a
CONTAINER ID        IMAGE                 COMMAND                CREATED             STATUS                    PORTS                                   NAMES
e63911262c94        csphere/mysql:5.5     "/scripts/start"       32 minutes ago                                                                        dbserver           
e274049db704        csphere/php-fpm:5.4   "/usr/bin/supervisor   2 days ago          Up 2 days                 22/tcp, 443/tcp, 0.0.0.0:8080->80/tcp   website             
2d36dbfc72a0        csphere/centos:7.1    "/usr/bin/supervisor   3 days ago          Up 3 days                 0.0.0.0:2222->22/tcp                    base                
0d1f6225836b        centos                "/bin/bash"            4 days ago          Exited (127) 4 days ago                                           naughty_engelbart   
[root@Optimus mysql]# 

更改為3307端口號，重新啟動container，顯示已經存在dbserver這個container了

[root@Optimus mysql]# docker run -d -p 3307:3306 --name debserver csphere/mysql:5.5
Error response from daemon: Conflict. The name "debserver" is already in use by container e63911262c94. You have to delete (or rename) that container to be able to reuse that name.

刪除dbserver容器

[root@Optimus mysql]# docker rm debserver
debserver

重新run container，并且端口映射為3307

[root@Optimus mysql]# docker run -d -p 3307:3306 --name dbserver csphere/mysql:5.5
076cb9396ca0aaa9ce0418dc8c5950aa227b0f1e1def92021fcaab39502c255e

查看容器

[root@Optimus mysql]# docker ps -a
CONTAINER ID        IMAGE                 COMMAND                CREATED             STATUS                    PORTS                                   NAMES
076cb9396ca0        csphere/mysql:5.5     "/scripts/start"       13 minutes ago      Up 13 minutes             22/tcp, 0.0.0.0:3307->3306/tcp          dbserver            
e274049db704        csphere/php-fpm:5.4   "/usr/bin/supervisor   2 days ago          Up 2 days                 22/tcp, 443/tcp, 0.0.0.0:8080->80/tcp   website             
2d36dbfc72a0        csphere/centos:7.1    "/usr/bin/supervisor   3 days ago          Up 3 days                 0.0.0.0:2222->22/tcp                    base                
0d1f6225836b        centos                "/bin/bash"            4 days ago          Exited (127) 4 days ago       

進入交互模式，登錄到容器中/bin/bash目錄下查看

[root@Optimus mysql]# docker exec -it dbserver /bin/bash
[root@076cb9396ca0 /]# 

登錄mysql,進入Mariadb中，可以進行任何數據庫的操作

 [root@076cb9396ca0 /]# mysql
Welcome to the MariaDB monitor.  Commands end with ; or g.
Your MariaDB connection id is 1
Server version: 5.5.56-MariaDB MariaDB Server

Copyright (c) 2000, 2017, Oracle, MariaDB Corporation Ab and others.

Type "help;" or "h" for help. Type "c" to clear the current input statement.

MariaDB [(none)]> 

查看數據庫

MariaDB [(none)]> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| performance_schema |
| test               |
+--------------------+
4 rows in set (0.17 sec)

MariaDB [(none)]> 

以上，一個具有Mariadb功能的docker容器創建成果。

退出mysql ，退出容器

MariaDB [(none)]> exit
Bye 
[root@076cb9396ca0 /]# exit
exit 

上面創建db容器的時候，沒有加-v參數。下面，使用docker run -v命令重新構建db容器。

docker run -v 掛載VOLUME參數

刪除容器

docker rm dbserver
不加任何參數時，不能刪除正在運行的container
docker rm -f dbserver
強制刪除

[root@Optimus mysql]# docker rm -f dbserver
dbserver

掛載-v和不掛載-v參數的區別
運行一個掛載-v參數的container
-v可以使用在數據庫、Nginx以及需要保存文件至宿主機下的服務上。

docker run -d -p 3307:3006 -v host_dir:container_dir
docker run -d -p 3307:3006 -v 宿主機的目錄/var/lib/docker/vfs/dir/mydata:容器的目錄/var/lib/mysql

mydata目錄和mysql的數據是一模一樣的，并且是同步的
這次不使用--name
我使用了3307做端口映射，因為本地3306端口被占用。如果沒有被占用，可以用3306:3306做端口映射
指定鏡像 csphere/mysql:5.5

[root@Optimus /]# docker run -d -p 3307:3306 -v /var/lib/docker/vfs/dir/mysqta:/var/lib/mysql csphere/mysql:5.5
9ad32fb968fe93daa349091b2725d9dc0b4ce414a9a13f4cf7751f0b15857d8f

查看容器

[root@Optimus /]# docker ps -a
CONTAINER ID        IMAGE                 COMMAND                CREATED             STATUS                    PORTS                                   NAMES
9ad32fb968fe        csphere/mysql:5.5     "/scripts/start"       29 minutes ago      Up 29 minutes             22/tcp, 0.0.0.0:3307->3306/tcp          romantic_brattain   
e274049db704        csphere/php-fpm:5.4   "/usr/bin/supervisor   5 days ago          Up 5 days                 22/tcp, 443/tcp, 0.0.0.0:8080->80/tcp   website             
2d36dbfc72a0        csphere/centos:7.1    "/usr/bin/supervisor   6 days ago          Up 6 days                 0.0.0.0:2222->22/tcp                    base                
0d1f6225836b        centos                "/bin/bash"            7 days ago          Exited (127) 7 days ago                                           naughty_engelbart   
[root@Optimus /]# 

沒有使用--name，自動匹配字符串 romantic_brattain 作為容器名稱

測試：掛載了-v以后，創建一個數據庫，然后刪除容器，數據是否還存在？

進入容器

docker exec -it containerID/containerName /bin/bash
進入容器中，容器必須是UP狀態，否則進不去。

[root@Optimus /]# docker exec -it 9ad /bin/bash
[root@9ad32fb968fe /]# 

登錄mysql

[root@9ad32fb968fe /]# mysql
Welcome to the MariaDB monitor.  Commands end with ; or g.
Your MariaDB connection id is 1
Server version: 5.5.56-MariaDB MariaDB Server

Copyright (c) 2000, 2017, Oracle, MariaDB Corporation Ab and others.

Type "help;" or "h" for help. Type "c" to clear the current input statement. 
MariaDB [(none)]> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| performance_schema |
| test               |
+--------------------+
4 rows in set (0.10 sec)

創建數據庫

MariaDB [(none)]> create database mydb;
Query OK, 1 row affected (0.12 sec)

查看數據庫

MariaDB [(none)]> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mydb               |
| mysql              |
| performance_schema |
| test               |
+--------------------+
5 rows in set (0.00 sec)

退出

MariaDB [(none)]> exit
Bye
e[root@9ad32fb968fe /]# exit
exit
[root@Optimus /]# 

查看一下剛才映射的目錄下有沒有mydb文件夾

[root@Optimus /]# ls /var/lib/docker/vfs/dir/mysqta/
aria_log.00000001  aria_log_control  ibdata1  ib_logfile0  ib_logfile1  mydb  mysql  mysql.sock  performance_schema  test

存在mydb目錄，說明宿主機已經和mysql的var目錄下的數據同步

查看mysql鏡像

[root@Optimus /]# docker ps -a
CONTAINER ID        IMAGE                 COMMAND                CREATED             STATUS                    PORTS                                   NAMES
9ad32fb968fe        csphere/mysql:5.5     "/scripts/start"       5 hours ago         Up 5 hours                22/tcp, 0.0.0.0:3307->3306/tcp          romantic_brattain   
e274049db704        csphere/php-fpm:5.4   "/usr/bin/supervisor   5 days ago          Up 5 days                 22/tcp, 443/tcp, 0.0.0.0:8080->80/tcp   website             
2d36dbfc72a0        csphere/centos:7.1    "/usr/bin/supervisor   6 days ago          Up 6 days                 0.0.0.0:2222->22/tcp                    base                
0d1f6225836b        centos                "/bin/bash"            7 days ago          Exited (127) 7 days ago                                           naughty_engelbart   
[root@Optimus /]# 

停止容器

[root@Optimus /]# docker stop 9ad
9ad

再次查看容器狀態為停止狀態

[root@Optimus /]# docker ps -a
CONTAINER ID        IMAGE                 COMMAND                CREATED             STATUS                        PORTS                                   NAMES
9ad32fb968fe        csphere/mysql:5.5     "/scripts/start"       5 hours ago         Exited (137) 37 seconds ago                                           romantic_brattain   
e274049db704        csphere/php-fpm:5.4   "/usr/bin/supervisor   5 days ago          Up 5 days                     22/tcp, 443/tcp, 0.0.0.0:8080->80/tcp   website             
2d36dbfc72a0        csphere/centos:7.1    "/usr/bin/supervisor   6 days ago          Up 6 days                     0.0.0.0:2222->22/tcp                    base                
0d1f6225836b        centos                "/bin/bash"            7 days ago          Exited (127) 7 days ago                                               naughty_engelbart   
[root@Optimus /]# 

查看UP狀態下的container

[root@Optimus /]# docker ps
CONTAINER ID        IMAGE                 COMMAND                CREATED             STATUS              PORTS                                   NAMES
e274049db704        csphere/php-fpm:5.4   "/usr/bin/supervisor   5 days ago          Up 5 days           22/tcp, 443/tcp, 0.0.0.0:8080->80/tcp   website             
2d36dbfc72a0        csphere/centos:7.1    "/usr/bin/supervisor   6 days ago          Up 6 days           0.0.0.0:2222->22/tcp                    base                
[root@Optimus /]# 

不用加參數，直接刪除容器

[root@Optimus /]# docker  rm 9ad
9ad

查看mysqta目錄下的文件依然還存在

[root@Optimus /]# ls /var/lib/docker/vfs/dir/mysqta/
aria_log.00000001  aria_log_control  ibdata1  ib_logfile0  ib_logfile1  mydb  mysql  mysql.sock  performance_schema  test
[root@Optimus /]# 

創建新的container，依然還可以繼續使用這個數據庫。

[root@Optimus /]# docker run -d -p 3307:3306 --name newdb -v /var/lib/docker/vfs/dir/mysqta:/var/lib/mysql csphere/mysql:5.5
8e266cd27a63495291c8b48f06204426c6d42b7c37ef8b86a6a6c124a5f5bafa
[root@Optimus /]# 

查看容器狀態

[root@Optimus /]# docker ps -a
CONTAINER ID        IMAGE                 COMMAND                CREATED             STATUS                    PORTS                                   NAMES
8e266cd27a63        csphere/mysql:5.5     "/scripts/start"       31 seconds ago      Up 29 seconds             22/tcp, 0.0.0.0:3307->3306/tcp          newdb               
e274049db704        csphere/php-fpm:5.4   "/usr/bin/supervisor   5 days ago          Up 5 days                 22/tcp, 443/tcp, 0.0.0.0:8080->80/tcp   website             
2d36dbfc72a0        csphere/centos:7.1    "/usr/bin/supervisor   6 days ago          Up 6 days                 0.0.0.0:2222->22/tcp                    base                
0d1f6225836b        centos                "/bin/bash"            7 days ago          Exited (127) 7 days ago                                           naughty_engelbart   
[root@Optimus /]# 

進入到容器中查看數據庫

[root@Optimus /]# docker exec -it newdb /bin/bash
[root@8e266cd27a63 /]# mysql
Welcome to the MariaDB monitor.  Commands end with ; or g.
Your MariaDB connection id is 1
Server version: 5.5.56-MariaDB MariaDB Server

Copyright (c) 2000, 2017, Oracle, MariaDB Corporation Ab and others.

Type "help;" or "h" for help. Type "c" to clear the current input statement.

MariaDB [(none)]> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mydb               |
| mysql              |
| performance_schema |
| test               |
+--------------------+
5 rows in set (0.08 sec)

MariaDB [(none)]> 

只要數據庫文件目錄存在，container可以隨意刪除重建，恢復很快。

構建DB容器完成。