Access yarn logs via Web UI - hadoop

Question

How can I access yarn job log via web ui?
I can view the job log via yarn manager web site. But every time yarn restart, the application list of yarn manager is empty. the picture is before restart
I can access application log via CLI command, even I restart yarn.
$HADOOP_HOME/bin/yarn logs -applicationId application_1499949542308_0020
The jobhistory server web ui is empty all the time
My log settings in yarn-site.xml and mapred-site.xml
<property>
<name>yarn.nodemanager.log-dirs</name>
<value>/home/hadoop/hadoop/nodemanager-logs</value>
</property>
<property>
<name>yarn.log-aggregation-enable</name>
<value>true</value>
</property>
<property>
<name>yarn.nodemanager.remote-app-log-dir</name>
<value>/app-logs</value>
</property>
<property>
<name>yarn.nodemanager.remote-app-log-dir-suffix</name>
<value>logs</value>
</property>
<property>
<name>yarn.log-aggregation.retain-seconds</name>
<value>604800</value>
</property>
<property>
<name>yarn.log.server.url</name>
<value>http://hdp03.hp.sp.prd.bmsre.com:19888/jobhistory/logs</value>
</property>
<property>
<name>mapreduce.jobhistory.address</name>
<value>hdp03.hp.sp.prd.bmsre.com:10020</value>
</property>
<property>
<name>mapreduce.jobhistory.webapp.address</name>
<value>hdp03.hp.sp.prd.bmsre.com:19888</value>
</property>

Answer 1

On Data Node, you can check the folder:
${HADOOP_HOME}/logs/userlogs
You just need to go to the folder which having the same name as the application id.

Answer 2

Yes, you can access Yarn retired jobs from Web UI.
access this url http://<jobtracker>:50070 to get the retired jobs.
With respect to your question you have restarted the yarn which means, a new log thread wakes up and does an upload of the logs to the configured location.
But in your question, does ' /app-logs' /app-logs path exists in your file-system. Please check.
There is a retention period, for how long the logs must be stored in that path and it is defined by the property name called yarn.log-aggregation.retain-seconds parameter.
To my understanding, the Job Tracker UI by default available at http://<jobtracker>:50070, exposes information on all currently running as well as retired MapReduce jobs and YARN has a JobHistory REST service that exposes details on finished applications.