9.3 DNSHealthCheck

Use this Knowledge Script to monitor the availability, CPU usage, memory usage, and name resolution of the Domain Name System (DNS) service. By default, this script attempts to restart the DNS service if the service is not running.

9.3.1 Resource Object

DNS service object

9.3.2 Default Schedule

The default interval for this script is Every five minutes.

9.3.3 Setting Parameter Values

Set the following parameters as needed:

Parameter	How to Set It
Event when DNS service is down?	Set to y to raise an event when the DNS service is down. The default is y.
Event when DNS name resolution fails?	Set to y to raise an event when name resolution fails. If set to y, the script attempts to resolve the specified hostname to the specified IP address. If the name resolution fails, an event is raised. If set to n, the script does not perform a name resolution lookup, and the Hostname for name resolution and Host IP address that should be returned parameters are ignored. The default is y.
Event when DNS CPU usage is over threshold?	Set to y to raise an event when the percentage of CPU consumed by the DNS service exceeds the threshold. The default is y.
Event when DNS memory usage is over threshold?	Set to y to raise an event when the amount of memory consumed by the DNS service exceeds the threshold. The default is y.
Collect data for DNS service up/down?	Set to y to collect data for charts and reports. If enabled, data collection returns: 100 -- the DNS service is running, or 0 -- the service is not running. The default is n.
Collect data for DNS CPU usage?	Set to y to collect data for charts and reports. If enabled, data collection returns the percentage of CPU consumed by the DNS service. The default is n.
Collect data for DNS memory usage?	Set to y to collect data for charts and reports. If enabled, data collection returns the amount of memory, in kilobytes (KB), consumed by the DNS service. The default is n.
Auto-start service?	Set to y to automatically restart the DNS service if it is down. The default is y.
Event severity level for service down; restart failed	Set the event severity level, from 1 to 40, to indicate the importance of an event in which the DNS service is down and the script cannot restart the service. The default is 5 (red event indicator).
Event severity level for service down; restart succeeded	Set the event severity level, from 1 to 40, to indicate the importance of an event in which the DNS service is down and the script successfully restarted the service. The default is 25 (blue event indicator).
Event severity level for service down; don’t restart	Set the event severity level, from 1 to 40, to indicate the importance of an event in which the DNS service is down and the Auto-start service? parameter is set to n. The default is 18 (yellow event indicator).
Event severity level for NS lookup failed	Set the event severity level, from 1 to 40, to indicate the importance of an event in which the DNS name resolution function fails. The default is 8 (red event indicator).
Event severity level for CPU usage exceeded threshold	Set the event severity level, from 1 to 40, to indicate the importance of an event in which CPU usage exceeds the threshold. The default is 8 (red event indicator).
Event severity level for memory usage exceeded threshold	Set the event severity level, from 1 to 40, to indicate the importance of an event in which memory usage exceeds the threshold. The default is 8 (red event indicator).
Event severity level for external command failed to execute	Set the event severity level, from 1 to 40, to indicate the importance of an event in which a system error prevents the execution of the DNS service. The default is 8 (red event indicator).
DNS process % CPU maximum threshold	Specify the maximum percentage of CPU resources that can be consumed by the DNS process before an event is raised. The default is 10%.
DNS process memory usage maximum threshold	Specify the maximum amount of memory resources that can be consumed by the DNS process before an event is raised. The default is 1024 KB.
Hostname for name resolution	Specify the name of the host to look up if you are using this script to test the hostname-to-IP address resolution. Default is localhost.
Host IP address that should be returned	Specify the correct IP address that should be returned by the DNS service if you are using this script to test the hostname-to-IP address resolution. The default is 127.0.0.1.