Horizontal discovery with patterns has four phases, just as horizontal discovery with
probes does. However, for the last two phases, Discovery triggers operations from a pattern,
rather than additional sets of probes.
Scanning phase
- Discovery first takes the
Shazzam probe (and then port
probes) and places it in a request in the External Communication Channel (ECC)
queue.
- The MID Server checks the ECC queue, retrieves the discovery request, and runs the
probes against the host and discovers open ports.
- The port probes scan common ports using several protocols, such as WMI, HTTP, SSH, and
SNMP.
- If one or more ports respond, the Shazzam probe sends information about the port back
to the ECC queue through the MID Server.
- Discovery checks the ECC queue to find out which ports responded, which identifies the
type of machine. For example, if Shazzam detects that the machine is listening on port
22, Discovery treats the machine as a UNIX or Linux machine.
Classification phase
- The Discovery application determines which classification probe to send to the newly
discovered device by using information in the record of the port probe that successfully
responded.
- Discovery puts the classification probe into the ECC queue.
- The MID Server checks the ECC queue, retrieves the discovery request, and runs the
classification probe.
- The classification probe retrieves additional information, such as which version of
the operating system is running on a machine. This information determines the class of
the CI that Discovery found. There is only one classification probe per discovered
device.
- The classification probe sends information back to the instance ECC queue through the
MID Server.
The Identification and Exploration phases
Patterns unify the Identification and Exploration phases of discovery.
- Discovery determines which classifier to use based on the class of the CI and the criteria
specified in all CI classifier records. The classifier specifies the Horizontal Pattern
probe, which in turn specifies which pattern to launch. The Horizontal pattern probe
also contains a sensor which does the actual work of updating the CMDB.
Note: Patterns need
applicative credentials to find applications running on host machines. Make sure you have
applicative credentials configured along with the credentials required to access the host
machine itself.
- The operations in the pattern specify the actions that Discovery needs to take for both the
identification and exploration phases. Discovery knows which identification rules to use based
on the CI type in the pattern, and Discovery makes inserts or updates to the CMDB based on
these rules. Only the Horizontal Discovery Sensor is used. Other probes and sensors are not
used.
