Azkaban Flow 2.0的使用
This commit is contained in:
		@@ -1,310 +1,296 @@
 | 
			
		||||
# Azkaban Flow 2.0的使用
 | 
			
		||||
 | 
			
		||||
# Azkaban Flow 2.0的使用
 | 
			
		||||
 | 
			
		||||
<nav>
 | 
			
		||||
<a href="#一Flow-20-简介">一、Flow 2.0 简介</a><br/>
 | 
			
		||||
<a href="#一Flow-20-简介">一、Flow 2.0 简介</a><br/>
 | 
			
		||||
    <a href="#11-Flow-20-的产生">1.1 Flow 2.0 的产生</a><br/>
 | 
			
		||||
<a href="#二YAML语法">二、YAML语法</a><br/>
 | 
			
		||||
<a href="#二YAML语法">二、YAML语法</a><br/>
 | 
			
		||||
    <a href="#21-基本规则">2.1 基本规则</a><br/>
 | 
			
		||||
    <a href="#22-对象的写法">2.2 对象的写法</a><br/>
 | 
			
		||||
    <a href="#23-map的写法">2.3 map的写法</a><br/>
 | 
			
		||||
    <a href="#23-数组的写法">2.3 数组的写法</a><br/>
 | 
			
		||||
    <a href="#25-单双引号">2.5 单双引号</a><br/>
 | 
			
		||||
    <a href="#26-特殊符号">2.6 特殊符号</a><br/>
 | 
			
		||||
<a href="#三简单任务调度">三、简单任务调度</a><br/>
 | 
			
		||||
<a href="#三简单任务调度">三、简单任务调度</a><br/>
 | 
			
		||||
    <a href="#31-任务配置">3.1 任务配置</a><br/>
 | 
			
		||||
    <a href="#32-打包上传">3.2 打包上传</a><br/>
 | 
			
		||||
<a href="#四多任务调度">四、多任务调度</a><br/>
 | 
			
		||||
<a href="#五内嵌流">五、内嵌流</a><br/>
 | 
			
		||||
</nav>
 | 
			
		||||
 | 
			
		||||
 | 
			
		||||
## 一、Flow 2.0 简介
 | 
			
		||||
 | 
			
		||||
### 1.1 Flow 2.0 的产生
 | 
			
		||||
 | 
			
		||||
Azkaban 目前同时支持Flow 1.0和Flow2.0,但是官方文档上更推荐使用2.0,因为Flow 1.0 会在将来的版本被移除。
 | 
			
		||||
 | 
			
		||||
>This section covers how to create your Azkaban flows using Azkaban Flow 2.0.Flow 1.0 will be deprecated in the future.
 | 
			
		||||
 | 
			
		||||
Flow 2.0设计的主要思想是提供1.0版本没有的流级定义。用户可以将属于给定流的所有.job / .properties文件合并到单个流定义文件中,而不是创建多个.job / .properties文件。配置文件以YAML格式定义,每个项目zip将包含多个流YAML文件和一个项目YAML文件。同时可以在YAML文件中的流内定义流,称为为嵌入流或子流。
 | 
			
		||||
 | 
			
		||||
### 1.2 基本结构
 | 
			
		||||
 | 
			
		||||
项目zip将包含多个流YAML文件,一个项目YAML文件以及可选库和源代码。Flow YAML文件的基本结构如下:
 | 
			
		||||
 | 
			
		||||
+ 每个Flow都在单个YAML文件中定义
 | 
			
		||||
+ 流文件以流名称命名。如:my-flow-name.flow
 | 
			
		||||
+ 包含DAG中的所有节点
 | 
			
		||||
+  每个节点可以是作业或流程
 | 
			
		||||
+  每个节点 可以拥有 name, type, config, dependsOn and nodes sections等属性
 | 
			
		||||
+  通过列出dependsOn列表中的父节点来指定节点依赖性
 | 
			
		||||
+ 包含与流相关的其他配置
 | 
			
		||||
+   当前.properties文件中流的所有常见属性都将迁移到每个流YAML文件中的config部分
 | 
			
		||||
 | 
			
		||||
官方提供了一个比较完善的配置样例,如下:
 | 
			
		||||
 | 
			
		||||
```yaml
 | 
			
		||||
config:
 | 
			
		||||
  user.to.proxy: azktest
 | 
			
		||||
  param.hadoopOutData: /tmp/wordcounthadoopout
 | 
			
		||||
  param.inData: /tmp/wordcountpigin
 | 
			
		||||
  param.outData: /tmp/wordcountpigout
 | 
			
		||||
 | 
			
		||||
# This section defines the list of jobs
 | 
			
		||||
# A node can be a job or a flow
 | 
			
		||||
# In this example, all nodes are jobs
 | 
			
		||||
nodes:
 | 
			
		||||
 # Job definition
 | 
			
		||||
 # The job definition is like a YAMLified version of properties file
 | 
			
		||||
 # with one major difference. All custom properties are now clubbed together
 | 
			
		||||
 # in a config section in the definition.
 | 
			
		||||
 # The first line describes the name of the job
 | 
			
		||||
 - name: AZTest
 | 
			
		||||
   type: noop
 | 
			
		||||
   # The dependsOn section contains the list of parent nodes the current
 | 
			
		||||
   # node depends on
 | 
			
		||||
   dependsOn:
 | 
			
		||||
     - hadoopWC1
 | 
			
		||||
     - NoOpTest1
 | 
			
		||||
     - hive2
 | 
			
		||||
     - java1
 | 
			
		||||
     - jobCommand2
 | 
			
		||||
 | 
			
		||||
 - name: pigWordCount1
 | 
			
		||||
   type: pig
 | 
			
		||||
   # The config section contains custom arguments or parameters which are
 | 
			
		||||
   # required by the job
 | 
			
		||||
   config:
 | 
			
		||||
     pig.script: src/main/pig/wordCountText.pig
 | 
			
		||||
 | 
			
		||||
 - name: hadoopWC1
 | 
			
		||||
   type: hadoopJava
 | 
			
		||||
   dependsOn:
 | 
			
		||||
     - pigWordCount1
 | 
			
		||||
   config:
 | 
			
		||||
     classpath: ./*
 | 
			
		||||
     force.output.overwrite: true
 | 
			
		||||
     input.path: ${param.inData}
 | 
			
		||||
     job.class: com.linkedin.wordcount.WordCount
 | 
			
		||||
     main.args: ${param.inData} ${param.hadoopOutData}
 | 
			
		||||
     output.path: ${param.hadoopOutData}
 | 
			
		||||
 | 
			
		||||
 - name: hive1
 | 
			
		||||
   type: hive
 | 
			
		||||
   config:
 | 
			
		||||
     hive.script: src/main/hive/showdb.q
 | 
			
		||||
 | 
			
		||||
 - name: NoOpTest1
 | 
			
		||||
   type: noop
 | 
			
		||||
 | 
			
		||||
 - name: hive2
 | 
			
		||||
   type: hive
 | 
			
		||||
   dependsOn:
 | 
			
		||||
     - hive1
 | 
			
		||||
   config:
 | 
			
		||||
     hive.script: src/main/hive/showTables.sql
 | 
			
		||||
 | 
			
		||||
 - name: java1
 | 
			
		||||
   type: javaprocess
 | 
			
		||||
   config:
 | 
			
		||||
     Xms: 96M
 | 
			
		||||
     java.class: com.linkedin.foo.HelloJavaProcessJob
 | 
			
		||||
 | 
			
		||||
 - name: jobCommand1
 | 
			
		||||
   type: command
 | 
			
		||||
   config:
 | 
			
		||||
     command: echo "hello world from job_command_1"
 | 
			
		||||
 | 
			
		||||
 - name: jobCommand2
 | 
			
		||||
   type: command
 | 
			
		||||
   dependsOn:
 | 
			
		||||
     - jobCommand1
 | 
			
		||||
   config:
 | 
			
		||||
     command: echo "hello world from job_command_2"
 | 
			
		||||
```
 | 
			
		||||
 | 
			
		||||
## 二、YAML语法
 | 
			
		||||
 | 
			
		||||
想要进行Flow流的配置,首先需要了解YAML ,YAML 是一种简洁的非标记语言,有着严格的格式要求的,如果你的格式配置失败,上传到Azkaban的时候就会抛出解析异常。
 | 
			
		||||
 | 
			
		||||
### 2.1 基本规则
 | 
			
		||||
 | 
			
		||||
1. 大小写敏感 
 | 
			
		||||
2. 使用缩进表示层级关系 
 | 
			
		||||
3. 缩进长度没有限制,只要元素对齐就表示这些元素属于一个层级。 
 | 
			
		||||
4. 使用#表示注释 
 | 
			
		||||
5. 字符串默认不用加单双引号,但单引号和双引号都可以使用,双引号不会对特殊字符转义。
 | 
			
		||||
6. YAML中提供了多种常量结构,包括:整数,浮点数,字符串,NULL,日期,布尔,时间。
 | 
			
		||||
 | 
			
		||||
### 2.2 对象的写法
 | 
			
		||||
 | 
			
		||||
```yaml
 | 
			
		||||
# value 与 : 符号之间必须要有一个空格
 | 
			
		||||
key: value
 | 
			
		||||
```
 | 
			
		||||
 | 
			
		||||
### 2.3 map的写法
 | 
			
		||||
 | 
			
		||||
```yaml
 | 
			
		||||
# 写法一 同一缩进的所有键值对属于一个map
 | 
			
		||||
key: 
 | 
			
		||||
    key1: value1
 | 
			
		||||
    key2: value2
 | 
			
		||||
 | 
			
		||||
# 写法二
 | 
			
		||||
{key1: value1, key2: value2}
 | 
			
		||||
```
 | 
			
		||||
 | 
			
		||||
### 2.3 数组的写法
 | 
			
		||||
 | 
			
		||||
```yaml
 | 
			
		||||
# 写法一 使用一个短横线加一个空格代表一个数组项
 | 
			
		||||
- a
 | 
			
		||||
- b
 | 
			
		||||
- c
 | 
			
		||||
 | 
			
		||||
# 写法二
 | 
			
		||||
[a,b,c]
 | 
			
		||||
```
 | 
			
		||||
 | 
			
		||||
### 2.5 单双引号
 | 
			
		||||
 | 
			
		||||
单引号和双引号都可以使用,双引号不会对特殊字符转义。
 | 
			
		||||
 | 
			
		||||
```yaml
 | 
			
		||||
s1: '内容\n字符串'
 | 
			
		||||
s2: "内容\n字符串"
 | 
			
		||||
 | 
			
		||||
转换后:
 | 
			
		||||
{ s1: '内容\\n字符串', s2: '内容\n字符串' }
 | 
			
		||||
```
 | 
			
		||||
 | 
			
		||||
### 2.6 特殊符号
 | 
			
		||||
 | 
			
		||||
`---`  YAML可以在同一个文件中,使用`---`表示一个文档的开始。
 | 
			
		||||
 | 
			
		||||
### 2.7 配置引用
 | 
			
		||||
 | 
			
		||||
在Azkaban中可以使用`${}`引用定义的配置,同时也建议将公共的参数抽取到config中,并使用`${}`进行引用。
 | 
			
		||||
 | 
			
		||||
 | 
			
		||||
 | 
			
		||||
## 三、简单任务调度
 | 
			
		||||
 | 
			
		||||
### 3.1 任务配置
 | 
			
		||||
 | 
			
		||||
新建`flow`配置文件
 | 
			
		||||
 | 
			
		||||
```yaml
 | 
			
		||||
nodes:
 | 
			
		||||
  - name: jobA
 | 
			
		||||
    type: command
 | 
			
		||||
    config:
 | 
			
		||||
      command: echo "Hello Azkaban Flow 2.0."
 | 
			
		||||
```
 | 
			
		||||
 | 
			
		||||
在当前的版本中,由于Azkaban是同时支持Flow 1.0 和 Flow 2.0的,如果你想让Azkaban知道你是希望以2.0方式运行,则需要新建一个`project`文件,指明是使用的Flow 2.0
 | 
			
		||||
 | 
			
		||||
```shell
 | 
			
		||||
azkaban-flow-version: 2.0
 | 
			
		||||
```
 | 
			
		||||
 | 
			
		||||
### 3.2 打包上传
 | 
			
		||||
 | 
			
		||||
<div align="center"> <img  src="https://github.com/heibaiying/BigData-Notes/blob/master/pictures/azkaban-simple.png"/> </div>
 | 
			
		||||
 | 
			
		||||
 | 
			
		||||
 | 
			
		||||
### 3.3 执行结果
 | 
			
		||||
 | 
			
		||||
由于在1.0 版本中已经介绍过web ui的使用,这里就不再赘述,对于1.0和2.0版本,只有配置的方式是不同的,其他上传执行的操作方式都是相同的。执行结果如下:
 | 
			
		||||
 | 
			
		||||
<div align="center"> <img  src="https://github.com/heibaiying/BigData-Notes/blob/master/pictures/azkaban-simle-result.png"/> </div>
 | 
			
		||||
 | 
			
		||||
## 四、多任务调度
 | 
			
		||||
 | 
			
		||||
和1.0给的案例一样,这里假设我们有五个任务(jobA——jobE),D任务需要在A,B,C任务执行完成后才能执行,而E任务则需要在D任务执行完成后才能执行。`Flow`配置如下。可以看到在1.0中我们需要分别定义五个配置文件,而在2.0中我们只需要一个配置文件即可完成配置。
 | 
			
		||||
 | 
			
		||||
```yaml
 | 
			
		||||
nodes:
 | 
			
		||||
  - name: jobE
 | 
			
		||||
    type: command
 | 
			
		||||
    config:
 | 
			
		||||
      command: echo "This is job E"
 | 
			
		||||
    # jobE depends on jobD
 | 
			
		||||
    dependsOn: 
 | 
			
		||||
      - jobD
 | 
			
		||||
    
 | 
			
		||||
  - name: jobD
 | 
			
		||||
    type: command
 | 
			
		||||
    config:
 | 
			
		||||
      command: echo "This is job D"
 | 
			
		||||
    # jobD depends on jobA、jobB、jobC
 | 
			
		||||
    dependsOn:
 | 
			
		||||
      - jobA
 | 
			
		||||
      - jobB
 | 
			
		||||
      - jobC
 | 
			
		||||
 | 
			
		||||
  - name: jobA
 | 
			
		||||
    type: command
 | 
			
		||||
    config:
 | 
			
		||||
      command: echo "This is job A"
 | 
			
		||||
 | 
			
		||||
  - name: jobB
 | 
			
		||||
    type: command
 | 
			
		||||
    config:
 | 
			
		||||
      command: echo "This is job B"
 | 
			
		||||
 | 
			
		||||
  - name: jobC
 | 
			
		||||
    type: command
 | 
			
		||||
    config:
 | 
			
		||||
      command: echo "This is job C"
 | 
			
		||||
```
 | 
			
		||||
 | 
			
		||||
## 五、内嵌流
 | 
			
		||||
 | 
			
		||||
Flow2.0 支持在一个Flow中定义另一个Flow,称为内嵌流或者子流。这里给出一个内嵌流的示例,其`Flow`配置如下:
 | 
			
		||||
 | 
			
		||||
```yaml
 | 
			
		||||
nodes:
 | 
			
		||||
  - name: jobC
 | 
			
		||||
    type: command
 | 
			
		||||
    config:
 | 
			
		||||
      command: echo "This is job C"
 | 
			
		||||
    dependsOn:
 | 
			
		||||
      - embedded_flow
 | 
			
		||||
 | 
			
		||||
  - name: embedded_flow
 | 
			
		||||
    type: flow
 | 
			
		||||
    config:
 | 
			
		||||
      prop: value
 | 
			
		||||
    nodes:
 | 
			
		||||
      - name: jobB
 | 
			
		||||
        type: command
 | 
			
		||||
        config:
 | 
			
		||||
          command: echo "This is job B"
 | 
			
		||||
        dependsOn:
 | 
			
		||||
          - jobA
 | 
			
		||||
 | 
			
		||||
      - name: jobA
 | 
			
		||||
        type: command
 | 
			
		||||
        config:
 | 
			
		||||
          command: echo "This is job A"
 | 
			
		||||
```
 | 
			
		||||
 | 
			
		||||
内嵌流的DAG图如下:
 | 
			
		||||
 | 
			
		||||
<div align="center"> <img  src="https://github.com/heibaiying/BigData-Notes/blob/master/pictures/azkaban-embeded-flow.png"/> </div>
 | 
			
		||||
 | 
			
		||||
执行情况如下:
 | 
			
		||||
 | 
			
		||||
<div align="center"> <img  src="https://github.com/heibaiying/BigData-Notes/blob/master/pictures/azkaban-embeded-success.png"/> </div>
 | 
			
		||||
 | 
			
		||||
 | 
			
		||||
 | 
			
		||||
## 参考资料
 | 
			
		||||
 | 
			
		||||
1. [Azkaban Flow 2.0 Design](https://github.com/azkaban/azkaban/wiki/Azkaban-Flow-2.0-Design)
 | 
			
		||||
2. [Getting started with Azkaban Flow 2.0](https://github.com/azkaban/azkaban/wiki/Getting-started-with-Azkaban-Flow-2.0)
 | 
			
		||||
 | 
			
		||||
## 一、Flow 2.0 简介
 | 
			
		||||
 | 
			
		||||
### 1.1 Flow 2.0 的产生
 | 
			
		||||
 | 
			
		||||
Azkaban 目前同时支持 Flow 1.0 和 Flow2.0 ,但是官方文档上更推荐使用Flow 2.0,因为Flow 1.0会在将来的版本被移除。Flow 2.0的主要设计思想是提供1.0所没有的流级定义。用户可以将属于给定流的所有`job / properties`文件合并到单个流定义文件中,其内容采用YAML语法进行定义,同时还支持在流中再定义流,称为为嵌入流或子流。
 | 
			
		||||
 | 
			
		||||
### 1.2 基本结构
 | 
			
		||||
 | 
			
		||||
项目zip将包含多个流YAML文件,一个项目YAML文件以及可选库和源代码。Flow YAML文件的基本结构如下:
 | 
			
		||||
 | 
			
		||||
+ 每个Flow都在单个YAML文件中定义;
 | 
			
		||||
+ 流文件以流名称命名。如:`my-flow-name.flow`;
 | 
			
		||||
+ 包含DAG中的所有节点;
 | 
			
		||||
+  每个节点可以是作业或流程;
 | 
			
		||||
+  每个节点 可以拥有 name, type, config, dependsOn 和 nodes sections等属性;
 | 
			
		||||
+  通过列出dependsOn列表中的父节点来指定节点依赖性;
 | 
			
		||||
+ 包含与流相关的其他配置;
 | 
			
		||||
+   当前properties文件中流的所有常见属性都将迁移到每个流YAML文件中的config部分。
 | 
			
		||||
 | 
			
		||||
官方提供了一个比较完善的配置样例,如下:
 | 
			
		||||
 | 
			
		||||
```yaml
 | 
			
		||||
config:
 | 
			
		||||
  user.to.proxy: azktest
 | 
			
		||||
  param.hadoopOutData: /tmp/wordcounthadoopout
 | 
			
		||||
  param.inData: /tmp/wordcountpigin
 | 
			
		||||
  param.outData: /tmp/wordcountpigout
 | 
			
		||||
 | 
			
		||||
# This section defines the list of jobs
 | 
			
		||||
# A node can be a job or a flow
 | 
			
		||||
# In this example, all nodes are jobs
 | 
			
		||||
nodes:
 | 
			
		||||
 # Job definition
 | 
			
		||||
 # The job definition is like a YAMLified version of properties file
 | 
			
		||||
 # with one major difference. All custom properties are now clubbed together
 | 
			
		||||
 # in a config section in the definition.
 | 
			
		||||
 # The first line describes the name of the job
 | 
			
		||||
 - name: AZTest
 | 
			
		||||
   type: noop
 | 
			
		||||
   # The dependsOn section contains the list of parent nodes the current
 | 
			
		||||
   # node depends on
 | 
			
		||||
   dependsOn:
 | 
			
		||||
     - hadoopWC1
 | 
			
		||||
     - NoOpTest1
 | 
			
		||||
     - hive2
 | 
			
		||||
     - java1
 | 
			
		||||
     - jobCommand2
 | 
			
		||||
 | 
			
		||||
 - name: pigWordCount1
 | 
			
		||||
   type: pig
 | 
			
		||||
   # The config section contains custom arguments or parameters which are
 | 
			
		||||
   # required by the job
 | 
			
		||||
   config:
 | 
			
		||||
     pig.script: src/main/pig/wordCountText.pig
 | 
			
		||||
 | 
			
		||||
 - name: hadoopWC1
 | 
			
		||||
   type: hadoopJava
 | 
			
		||||
   dependsOn:
 | 
			
		||||
     - pigWordCount1
 | 
			
		||||
   config:
 | 
			
		||||
     classpath: ./*
 | 
			
		||||
     force.output.overwrite: true
 | 
			
		||||
     input.path: ${param.inData}
 | 
			
		||||
     job.class: com.linkedin.wordcount.WordCount
 | 
			
		||||
     main.args: ${param.inData} ${param.hadoopOutData}
 | 
			
		||||
     output.path: ${param.hadoopOutData}
 | 
			
		||||
 | 
			
		||||
 - name: hive1
 | 
			
		||||
   type: hive
 | 
			
		||||
   config:
 | 
			
		||||
     hive.script: src/main/hive/showdb.q
 | 
			
		||||
 | 
			
		||||
 - name: NoOpTest1
 | 
			
		||||
   type: noop
 | 
			
		||||
 | 
			
		||||
 - name: hive2
 | 
			
		||||
   type: hive
 | 
			
		||||
   dependsOn:
 | 
			
		||||
     - hive1
 | 
			
		||||
   config:
 | 
			
		||||
     hive.script: src/main/hive/showTables.sql
 | 
			
		||||
 | 
			
		||||
 - name: java1
 | 
			
		||||
   type: javaprocess
 | 
			
		||||
   config:
 | 
			
		||||
     Xms: 96M
 | 
			
		||||
     java.class: com.linkedin.foo.HelloJavaProcessJob
 | 
			
		||||
 | 
			
		||||
 - name: jobCommand1
 | 
			
		||||
   type: command
 | 
			
		||||
   config:
 | 
			
		||||
     command: echo "hello world from job_command_1"
 | 
			
		||||
 | 
			
		||||
 - name: jobCommand2
 | 
			
		||||
   type: command
 | 
			
		||||
   dependsOn:
 | 
			
		||||
     - jobCommand1
 | 
			
		||||
   config:
 | 
			
		||||
     command: echo "hello world from job_command_2"
 | 
			
		||||
```
 | 
			
		||||
 | 
			
		||||
## 二、YAML语法
 | 
			
		||||
 | 
			
		||||
想要使用 Flow 2.0 进行工作流的配置,首先需要了解YAML 。YAML 是一种简洁的非标记语言,有着严格的格式要求的,如果你的格式配置失败,上传到Azkaban的时候就会抛出解析异常。
 | 
			
		||||
 | 
			
		||||
### 2.1 基本规则
 | 
			
		||||
 | 
			
		||||
1. 大小写敏感 ;
 | 
			
		||||
2. 使用缩进表示层级关系 ;
 | 
			
		||||
3. 缩进长度没有限制,只要元素对齐就表示这些元素属于一个层级; 
 | 
			
		||||
4. 使用#表示注释 ;
 | 
			
		||||
5. 字符串默认不用加单双引号,但单引号和双引号都可以使用,双引号表示不需要对特殊字符进行转义;
 | 
			
		||||
6. YAML中提供了多种常量结构,包括:整数,浮点数,字符串,NULL,日期,布尔,时间。
 | 
			
		||||
 | 
			
		||||
### 2.2 对象的写法
 | 
			
		||||
 | 
			
		||||
```yaml
 | 
			
		||||
# value 与 : 符号之间必须要有一个空格
 | 
			
		||||
key: value
 | 
			
		||||
```
 | 
			
		||||
 | 
			
		||||
### 2.3 map的写法
 | 
			
		||||
 | 
			
		||||
```yaml
 | 
			
		||||
# 写法一 同一缩进的所有键值对属于一个map
 | 
			
		||||
key: 
 | 
			
		||||
    key1: value1
 | 
			
		||||
    key2: value2
 | 
			
		||||
 | 
			
		||||
# 写法二
 | 
			
		||||
{key1: value1, key2: value2}
 | 
			
		||||
```
 | 
			
		||||
 | 
			
		||||
### 2.3 数组的写法
 | 
			
		||||
 | 
			
		||||
```yaml
 | 
			
		||||
# 写法一 使用一个短横线加一个空格代表一个数组项
 | 
			
		||||
- a
 | 
			
		||||
- b
 | 
			
		||||
- c
 | 
			
		||||
 | 
			
		||||
# 写法二
 | 
			
		||||
[a,b,c]
 | 
			
		||||
```
 | 
			
		||||
 | 
			
		||||
### 2.5 单双引号
 | 
			
		||||
 | 
			
		||||
支持单引号和双引号,但双引号不会对特殊字符进行转义:
 | 
			
		||||
 | 
			
		||||
```yaml
 | 
			
		||||
s1: '内容\n字符串'
 | 
			
		||||
s2: "内容\n字符串"
 | 
			
		||||
 | 
			
		||||
转换后:
 | 
			
		||||
{ s1: '内容\\n字符串', s2: '内容\n字符串' }
 | 
			
		||||
```
 | 
			
		||||
 | 
			
		||||
### 2.6 特殊符号
 | 
			
		||||
 | 
			
		||||
一个YAML文件中可以包括多个文档,使用`---`进行分割。
 | 
			
		||||
 | 
			
		||||
### 2.7 配置引用
 | 
			
		||||
 | 
			
		||||
Flow 2.0 建议将公共参数定义在`config`下,并通过`${}`进行引用。
 | 
			
		||||
 | 
			
		||||
 | 
			
		||||
 | 
			
		||||
## 三、简单任务调度
 | 
			
		||||
 | 
			
		||||
### 3.1 任务配置
 | 
			
		||||
 | 
			
		||||
新建`flow`配置文件:
 | 
			
		||||
 | 
			
		||||
```yaml
 | 
			
		||||
nodes:
 | 
			
		||||
  - name: jobA
 | 
			
		||||
    type: command
 | 
			
		||||
    config:
 | 
			
		||||
      command: echo "Hello Azkaban Flow 2.0."
 | 
			
		||||
```
 | 
			
		||||
 | 
			
		||||
在当前的版本中,Azkaban同时支持 Flow 1.0 和 Flow 2.0,如果你希望以2.0的方式运行,则需要新建一个`project`文件,指明是使用的是Flow 2.0:
 | 
			
		||||
 | 
			
		||||
```shell
 | 
			
		||||
azkaban-flow-version: 2.0
 | 
			
		||||
```
 | 
			
		||||
 | 
			
		||||
### 3.2 打包上传
 | 
			
		||||
 | 
			
		||||
<div align="center"> <img  src="https://github.com/heibaiying/BigData-Notes/blob/master/pictures/azkaban-simple.png"/> </div>
 | 
			
		||||
 | 
			
		||||
 | 
			
		||||
 | 
			
		||||
### 3.3 执行结果
 | 
			
		||||
 | 
			
		||||
由于在1.0 版本中已经介绍过Web UI的使用,这里就不再赘述。对于1.0和2.0版本,只有配置方式有所不同,其他上传执行的方式都是相同的。执行结果如下:
 | 
			
		||||
 | 
			
		||||
<div align="center"> <img  src="https://github.com/heibaiying/BigData-Notes/blob/master/pictures/azkaban-simle-result.png"/> </div>
 | 
			
		||||
 | 
			
		||||
## 四、多任务调度
 | 
			
		||||
 | 
			
		||||
和1.0给出的案例一样,这里假设我们有五个任务(jobA——jobE), D 任务需要在A,B,C任务执行完成后才能执行,而 E 任务则需要在 D 任务执行完成后才能执行,相关配置文件应如下。可以看到在1.0中我们需要分别定义五个配置文件,而在2.0中我们只需要一个配置文件即可完成配置。
 | 
			
		||||
 | 
			
		||||
```yaml
 | 
			
		||||
nodes:
 | 
			
		||||
  - name: jobE
 | 
			
		||||
    type: command
 | 
			
		||||
    config:
 | 
			
		||||
      command: echo "This is job E"
 | 
			
		||||
    # jobE depends on jobD
 | 
			
		||||
    dependsOn: 
 | 
			
		||||
      - jobD
 | 
			
		||||
    
 | 
			
		||||
  - name: jobD
 | 
			
		||||
    type: command
 | 
			
		||||
    config:
 | 
			
		||||
      command: echo "This is job D"
 | 
			
		||||
    # jobD depends on jobA、jobB、jobC
 | 
			
		||||
    dependsOn:
 | 
			
		||||
      - jobA
 | 
			
		||||
      - jobB
 | 
			
		||||
      - jobC
 | 
			
		||||
 | 
			
		||||
  - name: jobA
 | 
			
		||||
    type: command
 | 
			
		||||
    config:
 | 
			
		||||
      command: echo "This is job A"
 | 
			
		||||
 | 
			
		||||
  - name: jobB
 | 
			
		||||
    type: command
 | 
			
		||||
    config:
 | 
			
		||||
      command: echo "This is job B"
 | 
			
		||||
 | 
			
		||||
  - name: jobC
 | 
			
		||||
    type: command
 | 
			
		||||
    config:
 | 
			
		||||
      command: echo "This is job C"
 | 
			
		||||
```
 | 
			
		||||
 | 
			
		||||
## 五、内嵌流
 | 
			
		||||
 | 
			
		||||
Flow2.0 支持在一个Flow中定义另一个Flow,称为内嵌流或者子流。这里给出一个内嵌流的示例,其`Flow`配置如下:
 | 
			
		||||
 | 
			
		||||
```yaml
 | 
			
		||||
nodes:
 | 
			
		||||
  - name: jobC
 | 
			
		||||
    type: command
 | 
			
		||||
    config:
 | 
			
		||||
      command: echo "This is job C"
 | 
			
		||||
    dependsOn:
 | 
			
		||||
      - embedded_flow
 | 
			
		||||
 | 
			
		||||
  - name: embedded_flow
 | 
			
		||||
    type: flow
 | 
			
		||||
    config:
 | 
			
		||||
      prop: value
 | 
			
		||||
    nodes:
 | 
			
		||||
      - name: jobB
 | 
			
		||||
        type: command
 | 
			
		||||
        config:
 | 
			
		||||
          command: echo "This is job B"
 | 
			
		||||
        dependsOn:
 | 
			
		||||
          - jobA
 | 
			
		||||
 | 
			
		||||
      - name: jobA
 | 
			
		||||
        type: command
 | 
			
		||||
        config:
 | 
			
		||||
          command: echo "This is job A"
 | 
			
		||||
```
 | 
			
		||||
 | 
			
		||||
内嵌流的DAG图如下:
 | 
			
		||||
 | 
			
		||||
<div align="center"> <img  src="https://github.com/heibaiying/BigData-Notes/blob/master/pictures/azkaban-embeded-flow.png"/> </div>
 | 
			
		||||
 | 
			
		||||
执行情况如下:
 | 
			
		||||
 | 
			
		||||
<div align="center"> <img  src="https://github.com/heibaiying/BigData-Notes/blob/master/pictures/azkaban-embeded-success.png"/> </div>
 | 
			
		||||
 | 
			
		||||
 | 
			
		||||
 | 
			
		||||
## 参考资料
 | 
			
		||||
 | 
			
		||||
1. [Azkaban Flow 2.0 Design](https://github.com/azkaban/azkaban/wiki/Azkaban-Flow-2.0-Design)
 | 
			
		||||
2. [Getting started with Azkaban Flow 2.0](https://github.com/azkaban/azkaban/wiki/Getting-started-with-Azkaban-Flow-2.0)
 | 
			
		||||
 | 
			
		||||
 
 | 
			
		||||
		Reference in New Issue
	
	Block a user