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ServiceNav offers the ability to discover the devices in the environment to be managed.
It can be used to obtain general information about the hosts (IP address, type, name, services in operation, active monitoring protocols, etc …), and to bring the device under monitoring.
The goal is to discover the devices on the network with a view to accelerating the deployment of monitoring.
A host’s disk partitions and network ports are discovered from the outset.
Discovery utilises the raw data returned by open-source tools and network discovery protocols (NMAP, SNMP, WMI …).
The diagram below shows the sequence of operations performed for each active IP address in the target discovery range:
Prerequisites for use:
The following 2 monitoring accounts must be configured:
– Windows Admin (to allow reading of WMI counters)
– SNMP or SNMPv3 Community Strings
In this example we will discover a single IP address and bring it under management; incorporating the automatically discovered elements (disk partitions/network ports).
Complete discovery documentation is available here => http://coservit.com/servicenav/en/documentation/monitoring-deployment/
There is also a short video on discovery which brings some of the points discussed “to life”: http://coservit.com/servicenav/en/servicenav-feature-videos/
A discovery is initiated by clicking on the Discovery button.
All that is required is to enter the address range or a comma-separated list of addresses to be interrogated.
NOTE: It is not possible to use DNS names for discovery.
The Account tab allows you to supply the necessary information in respect Windows Admin and SNMP accounts.
By default, credentials are inherited from site monitoring accounts but it is possible to override them during the discovery.
Clicking the Apply button starts the discovery. A progress bar appears and this is automatically refreshed every 15 seconds. This makes it possible to visually see the progress of the discovery.
The results table is the core of the discovery module. It allows for review and use of data retrieved by the discovery.
The results show the success or failure of attempting to use the 3 tested protocols
ping: The monitoring box is able to ping the device
SNMP: The monitoring box can interrogate the devices MIB tree.
WMI: The monitoring box can make a successful WMI connection on Windows servers.
As previously mentioned, by default, partitions are discovered by the SNMP protocol as well as any network ports.
The discovery therefore makes it possible to automatically add checks for devices where SNMP access is successful.
This is very useful, especially when monitoring a switch that may have many network interfaces.
If the SNMP protocol is in CRITICAL (Red) status, then no components are discovered.
The good practice is to understand why the status is not OK before bringing any devices under monitoring.
Once the discovery is complete, devices may be monitored.
To do this, select the host and click on the “Add to monitoring” button.
If no host or service templates are applied when a host it is added to monitoring, and the check box “Add automatically discovered services” is checked, then the disk partitions and interfaces will be automatically added, and monitored.
PS: In some circumstances, the discovery of ports and partitions may not desirable; for example, in cases where devices always have the same configuration. It is then possible to create templates that will be applied to the devices without monitoring the automatically discovered elements.
When the host is added to monitoring, the result is as follows:
When a change is made to an already monitored device, some checks may no longer be appropriate or no longer.
Examples could be: the addition of a network card, a disk or partition.
Example scenario: I move a VM from one ESX host to another during a maintenance.
The monitored VM’s network card may send an alert or enter an unknown state.
When I look at the “Network Traffic VMware Virtual Ethernet Adapter for vmxnet3” service setting, the interface number is # 27
As I do not know the interface number assigned when the VM was moved, I will use the discovery module to find this number.
I go to the discovery module and I re-register my machine (even if it is already being monitored)
Now I see the number of the active interface. In this case, I must therefore replace the interface #27 with #12 in the service configuration.
Then my check will be operational again.