switchdiscover [-h| –help]

switchdiscover [-v| –version]

switchdiscover [noderange|–range ip_ranges] [-V] [-w][-r|-x|-z][-s scan_methods]


The switchdiscover command scans the subnets and discovers all the swithches on the subnets. The command takes a list of subnets as input. The default subnets are the ones that the xCAT management node is on. It uses nmap command to discover the switches. However, you can specify other discovery methods such as lldp with -s flag. You can write the discovered switches into xCAT database with -w flag. This command supports may output formats such as xml(-x), raw(-r) and stanza(-z) in addition to the default format.

To view all the switches defined in the xCAT databasee use lsdef -w “nodetype=switch” command.

For lldp method, please make sure that lldpd package is installed and lldpd is running on the xCAT management node. lldpd comes from xcat-dep packge or you can get it from http://vincentbernat.github.io/lldpd/installation.html.



The switches which the user want to discover. If the user specify the noderange, switchdiscover will just return the switches in the node range. Which means it will help to add the new switches to the xCAT database without modifying the existed definitions. But the switches’ name specified in noderange should be defined in database in advance. The ips of the switches will be defined in /etc/hosts file. This command will fill the switch attributes for the switches defined.


Display usage message.


Specify one or more IP ranges. Each can be an ip address ( or an ip range ( If the range is huge, for example,, the switch discover may take a very long time to scan. So the range should be exactly specified.

For nmap scan method, it accepts multiple formats. For example,, 40-41.1-2.3-4.1-100.

If the range is not specified, the command scans all the subnets that the active network interfaces (eth0, eth1) are on where this command is issued.


Display Raw responses.


It is a comma separated list of methods for switch discovery. The possible switch scan methods are: lldp and nmap. The default is nmap.


Command Version.


Verbose output.


Writes output to xCAT database.


XML formated output.


Stanza formated output.


0 The command completed successfully.

1 An error has occurred.



To discover the switches on some subnets:

switchdiscover –range,,


To do the switch discovery and save them to the xCAT database:

switchdiscover –range -w

It is recommended to run makehosts after the switches are saved in the DB.


To use lldp mathod to discover the switches:

switchdiscover -s lldp