Specifications

Health monitors
BIG-IP® Reference Guide 4 - 139
Selecting the monitor template
Selecting a template is straightforward. Like icmp, each of the templates has
a type based on the type of service it checks, for example, http, https, ftp,
pop3, and takes that type as its name. (Exceptions are port-specific
templates, like https_443, and the external template, which calls a
user-supplied program.) To select a template, simply select the one that
corresponds in name and/or type to the service you want to check. If more
than one service is to be checked, for example http and https, more than
one monitor can be placed on the node. (This creates a rule, namely that the
node will not be considered up unless both monitors run successful checks.)
You may not want to check all services available on a node specifically. If
you want to verify only that the destination IP address is alive, or that the
path to it through a transparent node is alive, use one of the simple
templates, icmp or tcp_echo. If you want to verify TCP only, use the
monitor template tcp.
All monitor templates are contained in the read-only file
/etc/base_monitors.conf. The following sections describe each of the
monitor templates, its function, and the information required to configure a
monitor from it. The templates are divided into three groups based on the
types of monitors they support: simple monitors, ECV (Extended Content
Verification) monitors, and EAV (Extended Application Verification)
monitors. Also described are the port-specific monitor templates, which are
derived from the other types.
Working with templates for simple monitors
Simple monitors are those that check node addresses only and verify simple
connections only. Templates for these monitors are icmp and tcp_echo.
Note
The templates icmp and tcp_echo are both usable as is, that is, they may be
associated with nodes. It is important to understand, however, that using a
template as is means that you are using the default attribute values. To
change any of these values, you have to configure a custom monitor based
on the template.
Using icmp
The icmp template uses Internet Control Message Protocol to make a simple
node check. The check is successful if a response to an ICMP_ECHO
datagram is received. icmp has no attributes other than the standard
interval, timeout, and dest.
monitor icmp {
#type icmp
interval 5
timeout 16
dest *
}
Figure 4.54 The icmp monitor template