Zenoss and the Art of Network Monitoring

Now, let's set up our Linux systems so they can talk to the Zenoss server. After installing and configuring the operating systems on our other Linux servers, install the Net-SNMP package on each using the following command on the Ubuntu server:

sudo apt-get install snmpd

And, on the Fedora server use:

yum install net-snmp 

Once the Net-SNMP packages are installed, edit out any other lines in the Access Control sections at the beginning of the /etc/snmp/snmpd.conf, and add the following lines:

##      sec.name  source      community
com2sec local     localhost   whatsourclearanceclarence
com2sec mynetwork 192.168.142.0/24   whatsourclearanceclarence

##  group.name  sec.model  sec.name
group MyROGroup	v1         local
group MyROGroup	v1         mynetwork
group MyROGroup	v2c        local
group MyROGroup	v2c        mynetwork

##         incl/excl subtree  mask
view all   included  .1        80

##             context sec.model sec.level prefix  read   write  notif
access MyROGroup ""      any       noauth  exact    all    none   none

Do not edit out any lines beneath the last Access Control Sections. Please note that the above is only a mildly restrictive configuration. Consult the snmpd.conf file or the Net-SNMP documentation if you want to tighten access. On the Ubuntu server, you also may have to change the following line in the /etc/snmp/default file to allow SNMP to bind to anything other than the local loopback address:

SNMPDOPTS='-Lsd -Lf /dev/null -u snmp -I -smux -p /var/run/snmpd.pid'

On the Windows server, access the Add/Remove Programs utility from the Control Panel. Click on the Add/Remove Windows Components button on the left. Scroll down the list of Components, check off Management and Monitoring Tools, and click on the Details button. Check Simple Network Management Protocol in the list, and click OK to install. Close the Add/Remove window, and go into the Services console from Administrative Tools in the Control Panel. Find the SNMP service in the list, right-click on it, and click on Properties to bring up the service properties tabs. Click on the Traps tab, and type in the community name. In the list of Trap Destinations, add the IP address of the Zenoss server. Now, click on the Security tab, and check off the Send authentication trap box, enter the community name, and give it READ-ONLY rights. Click OK, and restart the service.

Return to the Zenoss management Web page. Click the Devices link to go into the subclass of /Devices/Servers/Windows, and on the zProperties tab, enter the name of a domain admin account and password in the zWinUser and zWinPassword fields. This account gives Zenoss access to the Windows Management Instrumentation (WMI) on your Windows systems. Make sure to click Save at the bottom of the page before navigating away.

Now that our systems have SNMP, we can add them into Zenoss. Devices can be added individually or by scanning the network. Let's do both. To add our Ubuntu server into Zenoss, click on the Add Device link under the Management navigation section. Enter the IP address of the server and the community name. Under Device Class Path, set the selection to /Server/Linux. You could add a variety of other hardware, software and Zenoss information on this page before adding a system, but at a minimum, an IP address name and community name is required (Figure 1). Click the Add Device button, and the discovery process runs. When the results are displayed, click on the link to the new device to access it.

Figure 1. Adding a Device into Zenoss

To scan the network for devices, click the Networks link under Browse By section of the navigation menu. If your network is not in the list, add it using CIDR notation. Once added, check the box next to your network and use the drop-down arrow to click on the Select Discover Devices option. You will see a similar results page as the one from before. When complete, click on the links at the bottom of the results page to access the new devices. Any device found will be placed in the /Discovered class. Because we should have discovered the Fedora server and the Windows server, they should be moved to the /Devices/Servers/Linux and /Devices/Servers/Windows classes, respectively. This can be done from each server's Status tab by using the main drop-down list and selecting Manage→Change Class.

If all has gone well, so far we have a functional SNMP monitoring system that is able to monitor heartbeat/availability (Figure 2) and performance information (Figure 3) on our systems. You can customize other various Status and Performance Monitors to meet your needs, but here we will use the default localhost monitors.

Figure 2. The Zenoss Dashboard

Figure 3. Performance data is collected almost immediately after discovery.