How to Configure EM12c to NOT Use Load Balancers

This may not come up very often, but for some reason, an administrator might have to reconfigure an EM12c environment to NOT use load balancers.

This could be due to:

1.  Hardware Issue on the Load Balancers
2.  Mis-configured Load Balancers
3.  Re-allocation of Load Balancer hardware for other purposes.

Whatever the reason may be, I noted that the instructions to set up the load balancers are easy to find, but not so clearly found are how to configure the EM12c environment to not use the load balancers once they’ve been put in place. To revert back to non-load balancer configuration:

  • You will need the SYSMAN password to perform the following tasks.
  • First step will require you to reconfigure/secure the OMS without the load balancers.
  • Second step is to secure each agent without the wallet credentials and load balancer information.

Tip:  If you have a large number of agents that will need to be re-secured, scripting the task may be advisable to limit the downtime and the overhead.

Reconfigure the OMS

Log onto the OMS host

Proceed to the $OMS_HOME and secure the OMS, telling it to bypass the load balancers in the parameters:

cd $OMS_HOME

./emctl stop oms -all
./emctl secure oms -no_slb
Oracle Enterprise Manager Cloud Control 12c Release 4
Copyright (c) 1996, 2014 Oracle Corporation.  All rights reserved.
Securing OMS... Started.
Enter Enterprise Manager Root (SYSMAN) Password :
Enter Agent Registration Password :
Securing OMS... Succeeded.

Verify Changes

Check the details of your OMS details to ensure that the change has taken place:

./emctl status oms -details
Oracle Enterprise Manager Cloud Control 12c Release 4
Copyright (c) 1996, 2014 Oracle Corporation.  All rights reserved.
Enter Enterprise Manager Root (SYSMAN) Password :
....
OMS is not configured with SLB or virtual hostname Agent Upload is unlocked.
...

Re-secure the Agents

Each agent, (outside the one on the OMS that was secured without the load balancers when you ran the command in the last step…) will need to be secured via the following command:

cd $AGENT_HOME

./emctl secure agent
Oracle Enterprise Manager Cloud Control 12c Release 4
Copyright (c) 1996, 2014 Oracle Corporation.  All rights reserved.
Agent is already stopped...   Done.
Securing agent...   Started.
Enter Agent Registration Password :
Securing agent...   Suceeded.

That is all there is to reverting your EM12c environment to pre-load balancer configuration!

 

 

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September 19th, 2014 by

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  • Javier Ruiz

    Will the ./emctl secure agent secure all the agents?

    Via the OEM tool you can secure all agents with just 3 clicks just in case anyone wanted to know.

  • Monowar

    Hi,

    After running ./emctl secure oms -no_slb
    –> SLB port become default HTPPS port and all the agents went to down
    state

    From Agent Status:
    Heartbeat Status: OMS is unreachable

    From OMS Status:
    HTTPS Upload Port : 4900

    Upload URL: https://:4900/empbs/upload

    Note: Port 4900 was defined for Load balancer

    $ ./emctl secure agent
    Oracle Enterprise Manager Cloud Control 12c Release 4
    Copyright (c) 1996, 2014 Oracle Corporation. All rights reserved.
    Agent is already stopped…
    Done.
    Securing agent… Started.
    Enter Agent Registration Password :
    Unable to connect to OMS at URL https://:4903/empbs
    Securing agent… Failed.

    To solve that, I define the secure port 4903 for OMS as below:

    $ ./emctl secure oms -sysman_pwd -reg_pwd
    -host -secure_port 4903

    All agents become available automatically after that.

    Thanks
    Monowar

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