问题
I'm getting below issue while accessing ApplicationMaster UI from the RM WebUI (hadoop 2.6.0). There is no standalone WebProxy server running. The Proxy is running as a part of ResourceManager.
"HTTP ERROR 500
Problem accessing /proxy/application_1431357703844_0004/. Reason:
Connection refused"
Log entries in resourcemanager logs:
2015-05-11 19:25:01,837 INFO webproxy.WebAppProxyServlet (WebAppProxyServlet.java:doGet(330)) - ubuntu is accessing unchecked http://slave1:51704/ which is the app master GUI of application_1431357703844_0004 owned by ubuntu 2015-05-11 19:25:01,845 WARN mortbay.log (Slf4jLog.java:warn(76)) - /proxy/application_1431357703844_0004/: java.net.ConnectException: Connection refused
When I do wget of the AppMaster Url from RM, below is the output
ubuntu@resource-manager:/mnt/logs/yarn$ wget -O- "http://slave1:51704/" --2015-05-11 19:26:47-- http://slave1:51704/ HTTP request sent, awaiting response... 302 Found Location: http://slave1:51704/mapreduce [following] --2015-05-11 19:26:47-- http://slave1:51704/mapreduce HTTP request sent, awaiting response... 302 Found Location: http://slave1:8088/proxy/application_1431357703844_0004/mapreduce [following] --2015-05-11 19:26:47-- http://slave1:8088/proxy/application_1431357703844_0004/mapreduce Connecting to slave1|:8088... failed: Connection refused.
When i do wget of same AppMaster URL from the node where appMaster is running, I got 200 response.
ubuntu@slave1:~$ wget -O- http://slave1:51704/ --2015-05-11 19:31:13-- http://slave1:51704/ Connecting to slave1|:51704... connected. HTTP request sent, awaiting response... 302 Found Location: http://slave1:51704/mapreduce [following] --2015-05-11 19:31:13-- http://slave1:51704/mapreduce HTTP request sent, awaiting response... 200 OK Length: 6846 (6.7K) [text/html]
The main difference to note here is, when the request was made from RM, the nodemanager redirected to a different URL "http://slave1:8088/proxy/application_1431357703844_0004/mapreduce" which resulted in "Connection refused". But when the request was made from where NM was running, it didn't redirect to above URL, but resulted in 200 response.
Please help me understand the differential behaviour of redirection and resolve the issue.
回答1:
You can specify the yarn.resourcemanager.webapp.address to your RM's host address in yarn-site.xml on NodeManager device.
<property>
<name>yarn.resourcemanager.webapp.address</name>
<value>rm.hostname.com:8088</value>
</property>
not
<property>
<name>yarn.resourcemanager.webapp.address</name>
<value>0.0.0.0:8088</value>
</property>
来源：https://stackoverflow.com/questions/30176322/hadoop2-yarn-applicationmaster-ui-connection-refused-issue