What Are Monitors
As the name suggests, monitors are a special type of modules used to monitor devices at specific intervals, and then to report any problems that have occurred inside the device or with certain services within the selected device. Each monitor automatically boots up every 5 minutes. You can, of course, run the monitor manually using the appropriate action in the table.
In order to assign the monitor to a device, go to the ‘Monitors’ section presenting the list of monitors assigned to the selected device. To assign a new monitor, enter the ‘Assign Monitor To Device’ form. Then, select the type of a monitor you are interested in in the ‘Select The Monitor Type’ field. After you have assigned the monitor to a device, you need to set the monitor configuration.
You can assign any number of monitors to a single device. Some of them can be assigned multiple times, such as Port Monitor or TCP Monitor. This way, you can monitor several interfaces, as well as host names or IP addresses selected in the configuration, on a single server.
One of the predefined monitors is Ping Monitor, which verifies if the device is available. The configuration of the monitor consists in determining the value of the warning threshold in milliseconds, as well as specifying the host name or IP address that will be monitored. If the warning threshold is exceeded, the monitor status is set to ‘problem’ and the system returns the corresponding error. In case the device is available in a timely manner, the monitor status will be set to ‘up’. Otherwise, the status will be set to ‘down’.
Ping Monitor uses the system command ‘fping’ to determine whether the device is available. Hostname is used as a parameter to an ‘fping’ command or, if hostname is empty, the system downloads device’s IP address. Basing on it, it checks if the device is achievable. If a warning threshold is exceeded, the monitor status is set to ‘problem’ and the system returns a specific error. If the device is available in a timely manner then the monitor status is set to ‘up’, otherwise the monitor status is set to ‘down’.
Port monitor regularly checks if the port does not exceed the set in the configuration limits. The configuration of this monitor is as follows:
- Monitored Port - the list of available ports for the device
- Units - units in which we want to set limit
- Limit Inbound Traffic - limit value for inbound traffic, 0 if we don’t want to use this limit
- Limit Outgoing Traffic - limit value for outgoing traffic, 0 if we don’t want to use this limit
- Limit Overall Traffic - limit value for inbound and outgoing traffic, 0 if we don’t want to use this limit
- Turn off interface once limit has been exceeded - determines whether the system should try to disable the port if the limit is exceeded
- Send an email once limit has been exceeded - determines if the system has to try to send an email to the administrator if the limit is exceeded
- Warning Threshold Inbound Traffic - the value of the alert threshold for incoming traffic, 0 if you do not want to use the limit
- Warning Threshold Outgoing Traffic - the value of the alert threshold for outgoing traffic, 0 if you do not want to use the limit
- Warning Threshold Overall Traffic - similar as above but for incoming and outgoing traffic
- Turn off interface once level has been exceeded - determines if the system should try to disable the port if the warning threshold is exceeded
- Add notification once level has been exceeded - determines if the system should try to add the system notification if the warning threshold is exceeded
TCP Monitor checks the host on the port for the response that will be returned. The response is matched to a regular expression for correctness and used to determine the monitor status.
IPMI Connection Monitor
Additionally, the system offers the possibility to verify the connection using the IPMI protocol. The verification is carried out by the IPMI Connection Monitor that regularly checks whether the connection is properly established.