应用开发入门

WordPress 后端存储需要依赖数据库，实例使用的 MySQL 数据库，该应用需要创建 2 个 docker 镜像。

由于需要实现配置变更及管理组件的自动升级，不能直接使用已有的 docker 镜像，需要进行一些改造，Docker 镜像默认启动的进程不能是应用本身的进程，而应该是 ，由 supervisor 来启动 drone 服务。

1、将 drone 和 nsenter 添加到镜像，然后安装 supervisor 并进行适当的配置。

• drone 是 OpenPitrix 的 Agent 服务，与 OpenPitrix 调度系统进行交互。
• nsenter 用来在 Docker 内进入 Host 执行一些指令，比如挂载硬盘、ssh 免密登录等。
• supervisor 用来为 drone 的自动升级提供支持服务。可在制作 Docker 镜像时从 镜像中拷贝获取 drone 和 nsenter 这两个可执行文件以及 supervisor 相关的启动脚本：

Dockerfile

其中 start-supervisord.sh 的内容如下：

#!/bin/sh
exec supervisord -n

2、制作 MySQL 镜像并上传到镜像仓库，请预先准备好 Docker 镜像仓库（ ${registry} 替换为您实际的镜像仓库的名字）。

$ docker build -t ${registry}/mysql .
$ docker push ${registry}/mysql

第二步：制作 Wordpress 镜像

conf.d/mysql_hostname.toml

[template]
src = "mysql_hostname.tmpl"
dest = "/opt/openpitrix/conf/mysql_hostname"
keys = [
   "/",
]

templates/mysql_hostname.tmpl

说明：tmpl 模版文件决定应用配置文件内容。drone 读取 metadata service 并刷新这些变量的值，如此例 range 这一行是读取 Mysql 节点的 IP 信息。了解更多参见 。

2、新建目录，并将上一步准备的两个模板文件拷贝到 /etc/confd/ 目录下。然后，可在制作 Docker 镜像时从 openpitrix/openpitrix:metadata 镜像中拷贝获取 drone 和 nsenter 可执行文件以及 supervisor 相关的启动脚本：

Dockerfile

FROM wordpress
COPY --from=openpitrix/openpitrix:metadata /usr/local/bin/drone /usr/local/bin/
COPY --from=openpitrix/openpitrix:metadata /usr/bin/nsenter /usr/bin/
RUN apt-get update && apt-get install -y supervisor
COPY --from=openpitrix/openpitrix:metadata /etc/supervisor.d/drone.ini /etc/supervisor/conf.d/drone.conf
COPY --from=openpitrix/openpitrix:metadata /usr/local/bin/start-drone.sh /usr/local/bin/start-drone.sh
COPY start-supervisord.sh /usr/local/bin/
ENTRYPOINT ["start-supervisord.sh"]
RUN mkdir -p /etc/confd/conf.d/
RUN mkdir -p /etc/confd/templates/
COPY conf.d/* /etc/confd/conf.d/
COPY templates/* /etc/confd/templates/

$ docker build -t ${registry}/wordpress .
$ docker push ${registry}/wordpress

准备应用配置包

以下命令默认下载最新的客户端工具，拷贝文件到指定的 bin 目录。以 v0.2.3 为例，执行命令时应替换为实际的下载版本号：

$ curl -L https://git.io/GetOpenPitrixBin | sh -
$ cd openpitrix-v0.2.3-bin/
$ cp * /usr/local/bin/

第二步：创建应用目录

其中 cluster.json.tmpl，config.json，package.json 这三个配置文件是必须的，详见 开发模板规范。

Wordpress/cluster.json.tmpl

{
    "name": "{{.cluster.name}}",
    "description": "{{.cluster.description}}",
    "subnet": "{{.cluster.subnet}}",
    "nodes": [
        {
            "role": "Mysql",
            "container": {
                "type": "docker",
                "image": "${registry}/mysql"
            },
            "count": 1,
            "cpu": "{{.cluster.Mysql.cpu}}",
            "memory": "{{.cluster.Mysql.memory}}",
            "services": {
                "start": {
                    "cmd": "MYSQL_ROOT_PASSWORD=wordpress MYSQL_ROOT_HOST=% docker-entrypoint.sh mysqld & sleep 10"
                }
            }
        },
        {
            "role": "Wordpress",
                "type": "docker",
                "image": "${registry}/wordpress"
            },
            "cpu": "{{.cluster.Wordpress.cpu}}",
            "memory": "{{.cluster.Wordpress.memory}}",
            "services": {
                "start": {
                    "order": 1,
                    "cmd": "WORDPRESS_DB_PASSWORD=wordpress WORDPRESS_DB_HOST=`cat /opt/openpitrix/conf/mysql_hostname` docker-entrypoint.sh apache2-foreground & sleep 10"
                }
            }
        }
    ]
}

Wordpress/config.json

{
    "type": "array",
    "properties": [
        {
            "key": "cluster",
            "description": "WORDPRESS properties",
            "type": "array",
            "properties": [
                {
                    "key": "name",
                    "label": "name",
                    "description": "The name of the WORDPRESS service",
                    "type": "string",
                    "default": "Wordpress",
                    "required": false
                },
                {
                    "key": "description",
                    "label": "description",
                    "description": "The description of the WORDPRESS service",
                    "type": "string",
                    "default": "",
                    "required": false
                },
                {
                    "key": "subnet",
                    "label": "Subnet",
                    "description": "Choose a subnet to join",
                    "type": "string",
                    "default": "",
                    "required": true
                },
                {
                    "key": "Mysql",
                    "label": "Mysql",
                    "description": "MySql properties",
                    "type": "array",
                    "properties": [
                        {
                            "key": "cpu",
                            "label": "CPU",
                            "description": "CPUs of each node",
                            "type": "integer",
                            "default": 1,
                            "range": [1,2,4,8,16],
                            "required": true
                        },
                        {
                            "key": "memory",
                            "label": "Memory",
                            "default": 2048,
                            "range": [2048,8192,16384,32768,49152],
                            "required": true
                        }
                    ]
                },
                {
                    "key": "Wordpress",
                    "label": "Wordpress",
                    "description": "Wordpress properties",
                    "type": "array",
                    "properties": [
                        {
                            "key": "cpu",
                            "label": "CPU",
                            "description": "CPUs of each node",
                            "type": "integer",
                            "default": 1,
                            "range": [1,2,4],
                            "required": true
                        },
                        {
                            "key": "memory",
                            "label": "Memory",
                            "description": "memory of each node (in MB)",
                            "type": "integer",
                            "default": 1024,
                            "range": [1024,2048,4096],
                            "required": true
                        }
                    ]
                }
            ]
        }
    ]
}

Wordpress/package.json

{
  "api_version":"v1",
  "name":"Wordpress",
  "version":"0.1.0",
  "app_version":"4.9.7",
  "keywords": [
    "wordpress",
    "blog",
    "http",
    "web",
    "application",
    "php",
    "cms"
  ],
  "description":"Web publishing platform for building blogs and websites.",
  "icon": "https://openpitrix.pek3a.qingstor.com/icon/wordpress_icon.png",
  "home": "http://www.wordpress.com/", 
  "maintainers": [
    {
      "email": "openpitrix@yunify.com",
      "name": "openpitrix"
    }
  ],
  "screenshots": [
    "https://openpitrix.pek3a.qingstor.com/icon/wordpress_snapshot1.png",
    "https://openpitrix.pek3a.qingstor.com/icon/wordpress_snapshot2.png"
}

第四步：打包应用

回到 Wordpress 上级目录，执行打包命令：