Information Technology Reference
In-Depth Information
Creating Alarms
As you've already learned, there are many different types of alarms that administrators might
want to create. These could be alarms that monitor resource consumption—such as how much
CPU time a VM is consuming or how much RAM an ESXi host has allocated—or these alarms
could monitor for specii c events, such as whenever a specii c distributed virtual port group is
modii ed. In addition, you've already learned that alarms can be created on a variety of different
objects within vCenter Server. Regardless of the type of alarm or the type of object to which that
alarm is attached, the basic steps for creating an alarm are the same. In the following sections,
we'll walk you through creating a few different alarms so that you have the opportunity to see
the options available to you.
Creating a Resource Consumption Alarm
First, let's create an alarm that monitors resource consumption. As discussed in Chapter 9,
“Creating and Managing Virtual Machines,” vCenter Server supports VM snapshots. These
snapshots capture a VM at a specii c point in time, allowing you to roll back (or revert) to that
state later. However, snapshots require additional space on disk, and monitoring disk space
usage by snapshots is an important task. In vSphere, vCenter Server lets you create an alarm
that monitors VM snapshot space.
Before you create a custom alarm, though, you should ask yourself a few questions. First, is
there an existing alarm that already handles this task for you? Browsing the list of predei ned
alarms available in vCenter Server shows that although some storage-related alarms are pres-
ent, there is no alarm that monitors snapshot disk usage. Second, if you're going to create a new
alarm, where is the appropriate place within vCenter Server to create that alarm? This refers to
the earlier discussion of scope: On what object should you create this alarm so that it is properly
scoped and will alert you only under the desired conditions? In this particular case, you'd want
to be alerted to any snapshot space usage that exceeds your desired threshold, so a higher-level
object such as the datacenter object or even the vCenter Server object would be the best place to
create the alarm.
You Must Use vCenter Server for Alarms
You can't create alarms by connecting directly to an ESXi host; vCenter Server provides the alarm
functionality. You must connect to a vCenter Server instance in order to work with alarms.
Perform the following steps to create an alarm that monitors VM snapshot disk space usage
for all VMs in a datacenter:
1.
Launch the vSphere Web Client if it is not already running, and connect to a vCenter
Server instance.
2.
Navigate to an inventory view, such as Hosts And Clusters or VMs And Templates.
