在大数据的当下，各种spark和hadoop的框架层出不穷。各种高端的计算框架，分布式任务如乱花般迷眼。你是否有这种困惑！——有了许多的分布式任务，但是每天需要固定时间跑任务，自己写个调度，既不稳定，又没有可靠的通知。
那么你应该是在找——Oozie。
Oozie是一款支持分布式任务调度的开源框架，它支持很多的分布式任务，比如map reduce,spark,sqoop,pig甚至shell等等。你可以以各种方式调度它们，把它们组成工作流。每个工作流节点可以串行也可以并行执行。
如果你定义好了一系列的任务，就可以开启工作流，设置一个coordinator调度器进行定时的调度了。
有了这些工作以后，还需要一个很重要的环节—— 就是邮件提醒。不管是任务执行成功还是失败，都可以发送邮件提醒。这样每天晚上收到任务成功的消息，就可以安心睡觉了。
因此，本篇就带你来看看如何在Oozie中使用Email。
Email Action
在Oozie中每个工作流的环节都被设计成一个Action，email就是其中的一个Action.
Email action可以在oozie中发送信息，在email action中必须指定接收的地址，主题subject和内容body。在接收地址参数中支持使用逗号分隔，添加多个邮箱地址。
email action是同步执行的，因此必须等到邮件发出后，这个action才算完成，才能执行下一个action。
email action里面的所有参数都可以使用EL表达式。
语法规则
<workflow-app name="[WF-DEF-NAME]" xmlns="uri:oozie:workflow:0.1">
...
<action name="[NODE-NAME]">
<email xmlns="uri:oozie:email-action:0.2">
<to>[COMMA-SEPARATED-TO-ADDRESSES]</to>
<cc>[COMMA-SEPARATED-CC-ADDRESSES]</cc> <!-- cc is optional -->
<subject>[SUBJECT]</subject>
<body>[BODY]</body>
<content_type>[CONTENT-TYPE]</content_type> <!-- content_type is optional -->
<attachment>[COMMA-SEPARATED-HDFS-FILE-PATHS]</attachment> <!-- attachment is optional -->
</email>
<ok to="[NODE-NAME]"/>
<error to="[NODE-NAME]"/>
</action>
...
</workflow-app>
to和cc命令指定了谁来接收邮件。可以通过逗号分隔来指定多个邮箱地址。to是必填项，cc是可选的。
主题subject和正文body用于指定邮件的标题和正文，email-action:0.2支持text/html这种格式的正文，默认是普通的文本"text/plain"
attachment用于在邮件中添加一个hdfs文件的附件，也可以通过逗号分隔符指定多个附件。如果路径声明的不全，那么也会被当做hdfs中的文件。本地文件是不能添加到附件中的。
配置
email action需要在oozie-site.xml中配置SMTP服务器配置。下面是需要配置的值：
oozie.email.smtp.host
这个值是SMTP服务器的地址，默认是loalhost
oozie.email.smtp.port
是SMTP服务器的端口号，默认是25.
oozie.email.from.address
发送邮件的地址，默认是oozie@localhost
oozie.email.smtp.auth
是否开启认证，默认不开启
oozie.email.smtp.username
如果开启认证，登录的用户名，默认是空
oozie.email.smtp.password
如果开启认证，用户对应的密码，默认是空
PS. 在linux可以通过find -name oozie-site.xml在当前目录下查找。在我们的CDH版本中这个文件在./etc/oozie/conf.dist/oozie-site.xml
遇到的问题
很多人会遇到无法发邮件的问题，首先是要开启SMTP服务，查看是否开启可以使用telnet localhost 25。
另外，如果使用的是企业邮箱，需要注意发件人的格式，必须符合企业邮箱的设置。并且收件人只能是企业邮箱的地址。
在Cloudera Mnager中的配置如下图：
样例
<workflow-app name="sample-wf" xmlns="uri:oozie:workflow:0.1">
...
<action name="an-email">
<email xmlns="uri:oozie:email-action:0.1">
<to>bob@initech.com,the.other.bob@initech.com</to>
<cc>will@initech.com</cc>
<subject>Email notifications for ${wf:id()}</subject>
<body>The wf ${wf:id()} successfully completed.</body>
</email>
<ok to="myotherjob"/>
<error to="errorcleanup"/>
</action>
...
</workflow-app>
上面的例子中，邮件发给了bob,the.other.bob以及抄送给will，并指定了邮件的标题和正文以及workflow的id。
附录
为了更多的了解Oozie，这里直接给出了Oozie相关的重要配置
oozie-site.xml配置
<?xml version="1.0"?>
<configuration>
<!--oozie-default.xml文件是默认的配置-->
<property>
<name>oozie.service.ProxyUserService.proxyuser.hue.hosts</name>
<value>*</value>
</property>
<property>
<name>oozie.service.ProxyUserService.proxyuser.hue.groups</name>
<value>*</value>
</property>
</configuration>
oozie-defualt.xml
<?xml version="1.0"?>
<?xml-stylesheet type="text/xsl" href="configuration.xsl"?>
<!--
Licensed to the Apache Software Foundation (ASF) under one
or more contributor license agreements. See the NOTICE file
distributed with this work for additional information
regarding copyright ownership. The ASF licenses this file
to you under the Apache License, Version 2.0 (the
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
-->
<configuration>
<!-- ************************** VERY IMPORTANT ************************** -->
<!-- This file is in the Oozie configuration directory only for reference. -->
<!-- It is not loaded by Oozie, Oozie uses its own privatecopy. -->
<!-- ************************** VERY IMPORTANT ************************** -->
<property>
<name>oozie.output.compression.codec</name>
<value>gz</value>
<description>
The name of the compression codec to use.
where codec class implements the interface org.apache.oozie.compression.CompressionCodec.
If oozie.compression.codecs is not specified, gz codec implementation is used by default.
</description>
</property>
<property>
<name>oozie.action.mapreduce.uber.jar.enable</name>
<value>false</value>
<description>
which specify the oozie.mapreduce.uber.jar configuration property will fail.
</description>
</property>
<property>
<name>oozie.processing.timezone</name>
<value>UTC</value>
<description>
is changed, note that GMT(+/-)#### timezones do not observe DST changes.
</description>
</property>
<!-- Base Oozie URL: <SCHEME>://<HOST>:<PORT>/<CONTEXT> -->
<property>
<name>oozie.base.url</name>
<value>http://localhost:8080/oozie</value>
<description>
Base Oozie URL.
</description>
</property>
<!-- Services -->
<property>
<name>oozie.system.id</name>
<value>oozie-${user.name}</value>
<description>
The Oozie system ID.
</description>
</property>
<property>
<name>oozie.systemmode</name>
<value>NORMAL</value>
<description>
System mode for Oozie at startup.
</description>
</property>
<property>
<name>oozie.delete.runtime.dir.on.shutdown</name>
<value>true</value>
<description>
If the runtime directory should be kept after Oozie shutdowns down.
</description>
</property>
<property>
<name>oozie.services</name>
<value>
org.apache.oozie.service.SchedulerService,
org.apache.oozie.service.InstrumentationService,
org.apache.oozie.service.MemoryLocksService,
org.apache.oozie.service.UUIDService,
org.apache.oozie.service.ELService,
org.apache.oozie.service.AuthorizationService,
org.apache.oozie.service.UserGroupInformationService,
org.apache.oozie.service.HadoopAccessorService,
/email
IMPORTANT: if the StoreServicePasswordService is active, it will reset this value with the
value given in
the console.
</description>
</property>
<property>
<name>oozie.service.JPAService.pool.max.active.conn</name>
<value>10</value>
<description>
Max number of connections.
</description>
</property>
<!-- SchemaService -->
<property>
<name>oozie.service.SchemaService.wf.schemas</name>
<value>
oozie-workflow-0.1.xsd,oozie-workflow-0.2.xsd,oozie-workflow-0.2.5.xsd,oozie-workflow-0.3.x
sd,oozie-workflow-0.4.xsd,
oozie-workflow-0.4.5.xsd,oozie-workflow-0.5.xsd,
shell-action-0.1.xsd,shell-action-0.2.xsd,shell-action-0.3.xsd,
email-action-0.1.xsd,email-action-0.2.xsd,
hive-action-0.2.xsd,hive-action-0.3.xsd,hive-action-0.4.xsd,hive-action-0.5.xsd,hive-action
-0.6.xsd,
sqoop-action-0.2.xsd,sqoop-action-0.3.xsd,sqoop-action-0.4.xsd,
ssh-action-0.1.xsd,ssh-action-0.2.xsd,
distcp-action-0.1.xsd,distcp-action-0.2.xsd,
oozie-sla-0.1.xsd,oozie-sla-0.2.xsd,
hive2-action-0.1.xsd, hive2-action-0.2.xsd,
spark-action-0.1.xsd,spark-action-0.2.xsd
</value>
<description>
List of schemas for workflows (separated by commas).
</description>
</property>
<property>
<name>oozie.service.SchemaService.wf.ext.schemas</name>
<value> </value>
<description>
List of additional schemas for workflows (separated by commas).
</description>
</property>
<property>
<name>oozie.service.SchemaService.coord.schemas</name>
/email
<description>
Base console URL for a workflow job.
</description>
</property>
<!-- ActionService -->
<property>
<name>oozie.service.ActionService.executor.classes</name>
<value>
org.apache.oozie.action.decision.DecisionActionExecutor,
org.apache.oozie.action.hadoop.JavaActionExecutor,
org.apache.oozie.action.hadoop.FsActionExecutor,
org.apache.oozie.action.hadoop.MapReduceActionExecutor,
org.apache.oozie.action.hadoop.PigActionExecutor,
org.apache.oozie.action.hadoop.HiveActionExecutor,
org.apache.oozie.action.hadoop.ShellActionExecutor,
org.apache.oozie.action.hadoop.SqoopActionExecutor,
org.apache.oozie.action.hadoop.DistcpActionExecutor,
org.apache.oozie.action.hadoop.Hive2ActionExecutor,
org.apache.oozie.action.ssh.SshActionExecutor,
org.apache.oozie.action.oozie.SubWorkflowActionExecutor,
org.apache.oozie.action.email.EmailActionExecutor,
org.apache.oozie.action.hadoop.SparkActionExecutor
</value>
<description>
List of ActionExecutors classes (separated by commas).
Only action types with associated executors can be used in workflows.
</description>
</property>
<property>
<name>oozie.service.ActionService.executor.ext.classes</name>
<value> </value>
<description>
List of ActionExecutors extension classes (separated by commas). Only action types with ass
ociated
executors can be used in workflows. This property is a convenience property to add extensio
ns to the built
in executors without having to include all the built in ones.
</description>
</property>
<!-- ActionCheckerService -->
<property>
<name>oozie.service.ActionCheckerService.action.check.interval</name>
/email
<description>
Comma separated AUTHORITY=SPARK_CONF_DIR, where AUTHORITY is the HOST:PORT of
the ResourceManager of a YARN cluster. The wildcard '*' configuration is
used when there is no exact match for an authority. The SPARK_CONF_DIR contains
the relevant spark-defaults.conf properties file. If the path is relative is looked within
the Oozie configuration directory; though the path can be absolute. This is only used
when the Spark master is set to either "yarn-client" or "yarn-cluster".
</description>
</property>
<property>
<name>oozie.service.SparkConfigurationService.spark.configurations.ignore.spark.yarn.jar</name>
<value>true</value>
<description>
If true, Oozie will ignore the "spark.yarn.jar" property from any Spark configurations spec
ified in
oozie.service.SparkConfigurationService.spark.configurations. If false, Oozie will not ign
ore it. It is recommended
to leave this as true because it can interfere with the jars in the Spark sharelib.
</description>
</property>
<property>
<name>oozie.email.attachment.enabled</name>
<value>true</value>
<description>
This value determines whether to support email attachment of a file on HDFS.
Set it false if there is any security concern.
</description>
</property>
<property>
<name>oozie.actions.default.name-node</name>
<value> </value>
<description>
The default value to use for the <name-node> element in applicable action types. Thi
s value will be used when
neither the action itself nor the global section specifies a <name-node>. As expecte
d, it should be of the form
"hdfs://HOST:PORT".
</description>
</property>
<property>
<name>oozie.actions.default.job-tracker</name>
<value> </value>
<description>
@
search hit BOTTOM, continuing at TOP
IMPORTANT: if the StoreServicePasswordService is active, it will reset this value with the
value given in
the console.
</description>
</property>
<property>
<name>oozie.service.JPAService.pool.max.active.conn</name>
<value>10</value>
<description>
Max number of connections.
</description>
</property>
<!-- SchemaService -->
<property>
<name>oozie.service.SchemaService.wf.schemas</name>
<value>
oozie-workflow-0.1.xsd,oozie-workflow-0.2.xsd,oozie-workflow-0.2.5.xsd,oozie-workflow-0.3.x
sd,oozie-workflow-0.4.xsd,
oozie-workflow-0.4.5.xsd,oozie-workflow-0.5.xsd,
shell-action-0.1.xsd,shell-action-0.2.xsd,shell-action-0.3.xsd,
email-action-0.1.xsd,email-action-0.2.xsd,
hive-action-0.2.xsd,hive-action-0.3.xsd,hive-action-0.4.xsd,hive-action-0.5.xsd,hive-action
-0.6.xsd,
sqoop-action-0.2.xsd,sqoop-action-0.3.xsd,sqoop-action-0.4.xsd,
ssh-action-0.1.xsd,ssh-action-0.2.xsd,
distcp-action-0.1.xsd,distcp-action-0.2.xsd,
oozie-sla-0.1.xsd,oozie-sla-0.2.xsd,
hive2-action-0.1.xsd, hive2-action-0.2.xsd,
spark-action-0.1.xsd,spark-action-0.2.xsd
</value>
<description>
List of schemas for workflows (separated by commas).
</description>
</property>
<property>
<name>oozie.service.SchemaService.wf.ext.schemas</name>
<value> </value>
<description>
List of additional schemas for workflows (separated by commas).
</description>
</property>
<property>
<name>oozie.service.SchemaService.coord.schemas</name>
/email
<description>
Base console URL for a workflow job.
</description>
</property>
<!-- ActionService -->
<property>
<name>oozie.service.ActionService.executor.classes</name>
<value>
org.apache.oozie.action.decision.DecisionActionExecutor,
org.apache.oozie.action.hadoop.JavaActionExecutor,
org.apache.oozie.action.hadoop.FsActionExecutor,
org.apache.oozie.action.hadoop.MapReduceActionExecutor,
org.apache.oozie.action.hadoop.PigActionExecutor,
org.apache.oozie.action.hadoop.HiveActionExecutor,
org.apache.oozie.action.hadoop.ShellActionExecutor,
org.apache.oozie.action.hadoop.SqoopActionExecutor,
org.apache.oozie.action.hadoop.DistcpActionExecutor,
org.apache.oozie.action.hadoop.Hive2ActionExecutor,
org.apache.oozie.action.ssh.SshActionExecutor,
org.apache.oozie.action.oozie.SubWorkflowActionExecutor,
org.apache.oozie.action.email.EmailActionExecutor,
org.apache.oozie.action.hadoop.SparkActionExecutor
</value>
<description>
List of ActionExecutors classes (separated by commas).
Only action types with associated executors can be used in workflows.
</description>
</property>
<property>
<name>oozie.service.ActionService.executor.ext.classes</name>
<value> </value>
<description>
List of ActionExecutors extension classes (separated by commas). Only action types with ass
ociated
executors can be used in workflows. This property is a convenience property to add extensio
ns to the built
in executors without having to include all the built in ones.
</description>
</property>
<!-- ActionCheckerService -->
<property>
<name>oozie.service.ActionCheckerService.action.check.interval</name>
/email
<description>
used when there is no exact match for an authority. The SPARK_CONF_DIR contains
the relevant spark-defaults.conf properties file. If the path is relative is looked within
the Oozie configuration directory; though the path can be absolute. This is only used
when the Spark master is set to either "yarn-client" or "yarn-cluster".
</description>
</property>
<property>
<name>oozie.service.SparkConfigurationService.spark.configurations.ignore.spark.yarn.jar</name>
<value>true</value>
<description>
If true, Oozie will ignore the "spark.yarn.jar" property from any Spark configurations spec
ified in
oozie.service.SparkConfigurationService.spark.configurations. If false, Oozie will not ign
ore it. It is recommended
to leave this as true because it can interfere with the jars in the Spark sharelib.
</description>
</property>
<property>
<name>oozie.email.attachment.enabled</name>
<value>true</value>
<description>
This value determines whether to support email attachment of a file on HDFS.
Set it false if there is any security concern.
</description>
</property>
<property>
<name>oozie.actions.default.name-node</name>
<value> </value>
<description>
The default value to use for the <name-node> element in applicable action types. Thi
s value will be used when
neither the action itself nor the global section specifies a <name-node>. As expecte
d, it should be of the form
"hdfs://HOST:PORT".
</description>
</property>
<property>
<name>oozie.actions.default.job-tracker</name>
<value> </value>
<description>
The default value to use for the <job-tracker> element in applicable action types. T
his value will be used when
neither the action itself nor the global section specifies a <job-tracker>. As expec
ted, it should be of the form
"HOST:PORT".
</description>
</property>
</configuration>