Introduction

The On-demand Monitoring System (OMS) tool is a Web application that periodically stores CPU allocation, utilization, and loads data to a database, providing real-time and historical data (day, week, month, quarter, and year). The OMS tool manages multiple Partition Load Manager groups just as a Partition Load Manager server does, and it uses xlpstat, a Partition Load Manager status retrieval command.

You can download the tool from this article. The features of OMS include:

• A database for CPU allocation, utilization, and CPU load
• Real-time data for CPU allocation, utilization, and CPU load
• Historical data for CPU allocation, utilization, and CPU load
• Consolidated CPU utilization data for a physical server

Benefits

The OMS tool and the Partition Load Manager provide real-time and historical resource allocation and utilization data. The historical trend data provides fundamental information for estimating return on investment (ROI), total cost of ownership (TCO), and the IT resource investment plan for the next year.

You can also identify a faulty or mis-configured Partition Load Manager policy by examining allocation status. The OMS tool accomplishes this by providing real-time and historical graphs and average, maximum, or minimum values on resource allocation and utilization. A Web-based interface is provided for easy usage.

How it works

The OMS tool is composed of a database to store resource status, a resource status update script, and a Web application for the user interface. As shown in Figure 1 below, the OMS tool retrieves a partition's resource status data using the Partition Load Manager snapshot xlpstat command. The data is stored in a round-robin database (RRD) data file, which enables historical resource status retrieval. Real-time and historical data is provided by the Web application, which is a set of perl-cgi scripts run by the IBM HTTP Server.

The following open source software is used:

• RRD for the database
• IBM HTTP Server and Perl for the Web server and Web application

Current CPU status graphs and data for a managed system are shown in Figure 2 below.

The historical graphs for CPU utilization and load of a selected partition are shown in Figure 3.

Required APAR

Due to the socket file accumulation issue, APAR IY95155 needs to be applied before running OMS. If you do not install this APAR, you might face authentication failure of RSCT, which PLM relies on.

Installing OMS

OMS should be installed on a server where the Partition Load Manager server is already running.

OMS requires the following software:

• Perl (install in AIX>® as default)
• RRDtool (requires libart_lgpl, freetype2, libpng, and zlib)
• IBM HTTP Server

Installing RRDtool

To install RRDtool, the libart, freetype2, libpng, and zlib libraries need to be installed first. Use the following commands:

# rpm -ivh libart_lgpl-2.3.16-1.aix4.3.ppc.rpm
# rpm -ivh freetype2-2.1.7-2.aix5.1.ppc.rpm
# rpm -ivh libpng-1.2.1-6.aix5.1.ppc.rpm
# rpm -ivh zlib-1.2.2-4.aix5.1.ppc.rpm
# rpm -ivh rrdtool-1.2.13-1.perl58.aix5.2.ppc.rpm

Testing RRDtool

After installing RRDtool, you need to test it to be sure it works. First, create an RRD database file executing the following command:

# rrdtool create test.rrd             \
           --start 920804400          \
           DS:speed:COUNTER:600:U:U   \
           RRA:AVERAGE:0.5:1:24       \
           RRA:AVERAGE:0.5:6:10

Next, fill the RRD database, as follows:

# rrdtool update test.rrd 920804700:12345 920805000:12357 920805300:12363
# rrdtool update test.rrd 920805600:12363 920805900:12363 920806200:12373
# rrdtool update test.rrd 920806500:12383 920806800:12393 920807100:12399
# rrdtool update test.rrd 920807400:12405 920807700:12411 920808000:12415
# rrdtool update test.rrd 920808300:12420 920808600:12422 920808900:12423

Finally, retrieve the data from the RRD database, as follows:

# rrdtool fetch test.rrd AVERAGE --start 920804400 --end 920809200

                         speed

920804700: nan
920805000: 4.0000000000e-02
920805300: 2.0000000000e-02
920805600: 0.0000000000e+00
920805900: 0.0000000000e+00
920806200: 3.3333333333e-02
920806500: 3.3333333333e-02
920806800: 3.3333333333e-02
920807100: 2.0000000000e-02
920807400: 2.0000000000e-02
920807700: 2.0000000000e-02
920808000: 1.3333333333e-02
920808300: 1.6666666667e-02
920808600: 6.6666666667e-03
920808900: 3.3333333333e-03
920809200: nan

Installing IBM HTTP Server

To install IBM HTTP Server, Java™ software is required. If you do not have the Java software installed, install IBM Java software first.

# java -jar setup.jar -silent

IBM HTTP Server should be installed in /usr/HTTPServer.

Changing IBM HTTP Server configuration

Before changing the IBM HTTP Server configuration, a user account must be created. It is recommended that you use oms for a user ID and oms as a group ID. Then, modify the value in /usr/HTTPServer/conf/httpd.conf, as follows:

User oms
Group nobody

DocumentRoot "/usr/local/plm/htdocs"
<Directory "/usr/local/plm/htdocs">
    Options Indexes FollowSymLinks MultiViews ExecCGI Includes
</Directory>

AddHandler cgi-script .cgi .pl				
AddHandler server-parsed .html

Preparing to run OMS

You need to copy the OMS fileset. OMS files are going to be located in the /usr/local/plm directory. The files are for OMS database management, OMS Web application, and OMS configuration. The following commands should be run as oms user account.

# cd /usr/local
# tar xvf plm-monitoring-tool.tar

The extracted directories and files' owner and group should be oms. If they are not, change ownership using the chown command.

Make sure that files have proper permission set, as follows:

• At least 644 for *.html
• At least 755 for *.pl
• At least 755 for directories

Configuring OMS

To run OMS, the OMS configuration file (/usr/local/plm/conf/grouplist.cfg) should contain the Partition Load Manager group name, Partition Load Manager policy file name, total CPU number, and the number for total memory (MB) for each Partition Load Manager group.

For example, the OMS configuration file looks like the following:

Group_svr3 policy.test 16  131072

Creating RRD database files

First, root authority is required for this operation. After creating the RRD files, change owner and group of the RRD files to oms.

# /usr/local/plm/bin/oms-create-rrd.pl

Changing the logo and OMS title

Replace /usr/local/plm/htdocs/images/client-logo.gif with your organization's logo image file; the recommended size is 100x35. The header title can be modified in /usr/local/plm/htdocs/header.html.

Registering OMS update script to the cron table of the root

The OMS update script should be added to cron table of the root using the crontab -e command, as follows:

####### OMS (PLM Monitoring System) data feeding every minute 
0,5,10,15,20,25,30,35,40,45,50,55 * * * * * /usr/local/plm/bin/oms-update.pl 2>/dev/null

Starting and stopping OMS

To start OMS, only IBM HTTP Server needs to be started. After starting IBM HTTP Server, OMS can be accessed with a Web browser, as follows:

# /usr/HTTPServer/bin/apachectl start

To stop OMS, IBM HTTP Server needs to be stopped, as follows:

# /usr/HTTPServer/bin/apachectl stop

If you want to stop using the OMS update script, comment out the cron entry.

Restrictions

Partition addition or deletion is not supported. The only way to do this is by recreating the OMS database file using oms-create-rrd.pl script -- but all the data will be lost.

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Table of contents

• Introduction
• How it works
• Installing OMS
• Preparing to run OMS
• Starting and stopping OMS
• Restrictions
• Download
• Resources
• About the author
• Comments

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