By Bethany Lapaglia on May 23, 2016
One of the common concerns of the Administrators of an Oracle Enterprise Manager (EM) environment is that when you have to take EM down for planned maintenance, you are blind to the status of some of your company’s most critical assets. Well, as of EM 13c, Oracle now has a solution for you! Introducing Always-On Monitoring – or AOM for short. Always-On Monitoring provides the capability of monitoring all or a specific list of targets using the same EM agents already deployed to these targets during complete downtime of the EM environment. It is especially useful for monitoring critical targets during planned EM downtime such as patching and/or upgrades. AOM will synchronize with EM for data such as notification contacts and is able to take the alerts from the EM agents and send email notifications to the identified downtime contacts. AOM can be configured and left running all the time so that it is ready to “take over” the alert notification for critical targets once notifications have been enabled. This blog contains the first of a couple of posts on AOM starting with the setup and configuration of the tool.
The setup/configuration of the AOM tool consists of the following steps:
1. AOM Installation
- The AOM application is included with the EM 13c software distribution under
the sysman/ems directory and is also available via the Self-Update function in
EM. The installation of the application
is as simple as unzipping the zip file in the location chosen for the AOM
install. An AOM installation consists of a database to hold the AOM repository,
and a server to run the AOM Instance. Chapter
12 of the Oracle Enterprise Manager Cloud Control Administrator’s Guide
contains the details steps required for installing AOM. This server must have JAVA version 1.7
installed. At this time, the AOM instance/application
must run on the EM OMS but the AOM repository database can be created on any
Oracle database server. With the EM 13.2 release, the AOM instance/application will be able to be installed on any host within the monitored environment.
2. Configure AOM Communication to EM - The configuration is pretty simple and is all handled via the script called emsca found under the AOM installation home in the scripts directory. (Fun Fact: the name of this script and the command line utility all start with ems rather than aom due to a pre-release name change of the product). This script will handle all of the necessary steps to configure AOM including the creation of the user and schema for the AOM repository. Once this configuration is complete, make sure that EM has an Email Server configured. At this time, AOM can only send email messages for the alerts and it uses the email server configuration that it gets from EM during synchronization. See "Configuring Email Servers in Enterprise Manager" for more details on how to setup Email Servers in EM.
3. Configuration of downtime contacts - The downtime contacts are those that will receive the email notifications in the event of an alert on the identified targets. Setting up the downtime contacts is done in your EM environment and can be done in a couple of different ways and is documented in the section “Configuring Downtime Contacts in Enterprise Manager”.
4. Synchronizing AOM and EM - This synchronization copies over the notification configuration and downtime contacts for the EM targets over to the AOM application. This should be done before starting AOM for the first time. It is a simple command using the AOM command line utility called emsctl. Here is a sample of the command:
% $AOM_HOME/scripts/emsctl sync
6. Configure EM for AOM - The final step in the configuration process is to tell EM to include the upload URL for the AOM service. Once this is done, EM will send this URL to all existing agents and any future agents. This makes this a one-time step that will then be handled for you as your number of agents change in the future. To get the AOM upload URL, issue the command below (the upload URL is in bold below):
% $AOM_HOME/scripts/emsctl status
Oracle Enterprise Manager Cloud Control 13c Release 1
Copyright (c) 1996, 2015 Oracle Corporation. All rights reserved.
Always-On Monitoring Version : 220.127.116.11.0
Always-On Monitoring Home : /u01/app/oracle/aom
Started At : January 13, 2016 4:11:01 PM PST
Last Repository Sync : February 2, 2016 1:41:17 PM PST
Upload URL : https://aomserver.domain:8081/upload
Always-On Monitoring Process ID : 15399
Always-On Monitoring Repository : (DESCRIPTION=(ADDRESS_LIST=(ADDRESS=(PROTOCOL=TCP)(HOST=aomRepo.domain)(PORT=1521)))(CONNECT_DATA=(SERVICE_NAME=aom)))
Enterprise Manager Repository : (DESCRIPTION=(ADDRESS_LIST=(ADDRESS=(PROTOCOL=TCP)(HOST=emServer.domain)(PORT=1521)))(CONNECT_DATA=(SERVICE_NAME=emdb)))
Notifications Enabled : false
Total Downtime Contacts Configured : 29Then issue the following emctl command to set the property in EM (note this is emctl and not emsctl) – substituting the information in bold below with the correct upoad url and sysman password for your environment:
% emctl set property -name "oracle.sysman.core.events.ems.emsURL" -value " https://aomserver.domain:8081/upload " -sysman_pwd sysman
% $AOM_HOME/scripts/emsctl start
Even though the setup of AOM is complete and it has been started, you will not receive any alerts when EM is down unless you enable notifications. As you probably guessed by now, this is done via the emsctl command:
% $AOM_HOME/scripts/emsctl enable_notification
A sync with EM is done each time you enable_notification unless you use the option –nosync. To disable the notification, use the same sort of command with the disable_notification option:
% $AOM_HOME/scripts/emsctl disable_notification
It is a good practice to leave AOM started but make sure you disable the notifications. Only enable them just before you shutdown EM for planned maintenance. REMEMBER that you will get more notification than you probably want if you leave this enabled all of the time because AOM has no knowledge of the notifications that EM is already doing.
To summarize, Always-On Monitoring offers a solution to the long-time problem of who monitors our critical targets when EM is down. The next blog will provide the details on how to configure AOM for High Availability and Disaster Recovery.