Use this Knowledge Script to check the health of the DNS server by monitoring memory and CPU usage for the DNS process and attempting a basic address look-up (nslookup) request. With this Knowledge Script, you can set separate thresholds for the maximum percentage of CPU and memory the DNS process should be using.
This script raises an event if:
CPU used by the DNS process exceeds the threshold
Memory used by the DNS process exceeds the threshold
The DNS process fails to respond to the look-up request
Because temporary spikes or increases in memory or CPU consumption are typically of less concern than look-up failures, the default event severity level signalling that the memory or CPU threshold has been crossed is a Warning event. For look-up failures, the default severity level indicates that the failure is a Severe event.
You can only use this Knowledge Script on computers that are running a DNS server.
Network folder
The default interval for this script is Every 30 minutes.
Set the following parameters as needed:
|
Description |
How to Set It |
|---|---|
|
Event if CPU usage is over threshold? (y/n) |
Set to y to raise events for CPU usage over the threshold in the interval. The default is y. |
|
Event if memory usage is over threshold? (y/n) |
Set to y to raise events for memory usage over the threshold in the interval. The default is y. |
|
Event if bind not running or nslookup fails? (y/n) |
Set to y to raise events when the DNS process is down or the look-up request fails in the interval. The default is y. |
|
Collect CPU usage data? (y/n) |
Set to y to collect CPU data for charts and reports. If set to y, the script returns the average percentage of CPU used. The default is n. |
|
Collect memory usage data? (y/n) |
Set to y to collect data for charts and reports. If set to y, the script returns the average percentage of memory the DNS process used. The default is n. |
|
Maximum CPU usage (%) threshold |
Enter a threshold for maximum percentage of CPU the DNS process should be allowed to use before raising an event. The default is 90% of available CPU. |
|
Maximum memory usage (%) threshold |
Enter a threshold for maximum percentage of memory the DNS process should be allowed to use before raising an event. The default is 50% of available memory. |
|
Site name to look for using nslookup |
Enter the name of the site you want the DNS server to look for using nslookup. |
|
Event severity when CPU usage (%) over the threshold |
Set the event severity level, from 1 to 40, to indicate the importance of the event reported when the percent of CPU usage crosses the threshold. The default is 15. |
|
Event severity when memory usage (%) over the threshold |
Set the event severity level, from 1 to 40, to indicate the importance of the event reported when the percent of memory usage crosses the threshold. The default is 15. |
|
Event severity when DNS is down or nslookup fails |
Set the event severity level, from 1 to 40, to indicate the importance of the event reported when the DNS is down or when nslookup fails. The default is 5. |
|
Event severity for internal failure |
Set the event severity level, from 1 to 40, to indicate the importance of an event in which this job experienced an internal error. The default is 5. |
|
Enable debugging? (y/n) |
Set to y to enable debugging. The default is n. |