DX APM : Not able to reach User Interface UI.

Products

• CA Application Performance Management Agent (APM / Wily / Introscope)
• CA Application Performance Management (APM / Wily / Introscope)
• INTROSCOPE
• DX Application Performance Management

Issue/Introduction

When login into a Tenant We seeing the following error on the browser; 

HTTP ERROR 500 javax.servlet.ServletException: org.springframework.web.util.NestedServletException: Request processing failed; nested exception is com.google.common.util.concurrent.UncheckedExecutionException: org.springframework.web.client.ResourceAccessException: I/O error on POST request for "http://apmservices-gateway:8004/session/validate": apmservices-gateway; nested exception is java.net.UnknownHostException: apmservices-gateway

URI:	/apm/appmap/ApmServer/
STATUS:	500
MESSAGE:	javax.servlet.ServletException: org.springframework.web.util.NestedServletException: Request processing failed; nested exception is com.google.common.util.concurrent.UncheckedExecutionException: org.springframework.web.client.ResourceAccessException: I/O error on POST request for "http://apmservices-gateway:8004/session/validate": apmservices-gateway; nested exception is java.net.UnknownHostException: apmservices-gateway
SERVLET:	rest-dispatcher
CAUSED BY:	javax.servlet.ServletException: org.springframework.web.util.NestedServletException: Request processing failed; nested exception is com.google.common.util.concurrent.UncheckedExecutionException: org.springframework.web.client.ResourceAccessException: I/O error on POST request for "http://apmservices-gateway:8004/session/validate": apmservices-gateway; nested exception is java.net.UnknownHostException: apmservices-gateway
CAUSED BY:	org.springframework.web.util.NestedServletException: Request processing failed; nested exception is com.google.common.util.concurrent.UncheckedExecutionException: org.springframework.web.client.ResourceAccessException: I/O error on POST request for "http://apmservices-gateway:8004/session/validate": apmservices-gateway; nested exception is java.net.UnknownHostException: apmservices-gateway
CAUSED BY:	com.google.common.util.concurrent.UncheckedExecutionException: org.springframework.web.client.ResourceAccessException: I/O error on POST request for "http://apmservices-gateway:8004/session/validate": apmservices-gateway; nested exception is java.net.UnknownHostException: apmservices-gateway
CAUSED BY:	org.springframework.web.client.ResourceAccessException: I/O error on POST request for "http://apmservices-gateway:8004/session/validate": apmservices-gateway; nested exception is java.net.UnknownHostException: apmservices-gateway
CAUSED BY:	java.net.UnknownHostException: apmservices-gateway

Environment

Release : 1.0

Component : APM Agents

Cause

Check the NFS mounting. Restart all the pods and now able to access the telnets.

Resolution

Somehow the NFS mount was missing. After re-mounting , I restarted all the pods and now able to access the telnet.