Could not read EMD_URL from agent configuration files in 12c

Today after OS patching, got below error when trying to check the status of the agent :-

==>./emctl status agent
Oracle Enterprise Manager Cloud Control 12c Release 4
Copyright (c) 1996, 2014 Oracle Corporation.  All rights reserved.
---------------------------------------------------------------
EMD_URL is null.
Could not read EMD_URL from agent configuration files

==>./emctl stop agent

Oracle Enterprise Manager Cloud Control 12c Release 4
Copyright (c) 1996, 2014 Oracle Corporation.  All rights reserved.
EMD_URL is null.
Could not read EMD_URL from agent configuration files

Cause :-

Configuration files for Agent corrupted or accidentally deleted.

Solution :-

Check for the emd.properties file in EM_AGENT_HOME/agent_inst/sysman/config folder
or check for the targets.xml file in EM_AGENT_HOME/agent_inst/sysman/emd folder

In my scenario , my emd.properties got corrupted

==>ls -ltr emd*
-rw------- 1 oracle sigdba 7709 Jan 19  2016 emd.properties.tzbak
-rw-r----- 1 oracle sigdba 7709 Jan 19  2016 emd.properties.2016-01-19-21-51-32
-rw-r----- 1 oracle sigdba 7734 Jan 19  2016 emd.properties.2016_01_19_09_51_36
-rw-r----- 1 oracle sigdba 7861 Oct 29 01:59 emd.properties.bak
-rw-r----- 1 oracle sigdba    0 Dec 16 01:01 emd.properties
[Hostname][oracle][AMIT2]

We can see the size of file is zero , by default Oracle keeps a backup of emd.properties file in the same directory, restore the file from that backup, I did the same

-rw-r----- 1 oracle sigdba  7861 Oct 29 01:59 emd.properties
-rw-r----- 1 oracle sigdba   155 Oct 29 01:59 private.properties
-rw-r----- 1 oracle sigdba   265 Dec 16 01:01 autotune.properties
-rw-r----- 1 oracle sigdba     0 Dec 16 01:01 emd.properties_20170113

Now again tried for a restart of the agent , it worked

==>./emctl stop agent

Oracle Enterprise Manager Cloud Control 12c Release 4

Copyright (c) 1996, 2014 Oracle Corporation.  All rights reserved.

Agent is Not Running

[Hostname][oracle][amit2]

/opt/oracle/product/agent/core/12.1.0.4.0/bin$

==>./emctl start agent

Oracle Enterprise Manager Cloud Control 12c Release 4

Copyright (c) 1996, 2014 Oracle Corporation.  All rights reserved.

Starting agent ..................... started.

If your emd.properties file is not corrupted but targets.xml is corrupted , then also Oracle keep a backup of that file in same folder , we can restore from that file.

I hope this article helped you.

Thanks

Amit Rath