After starting the TNSR CLI, the administrator is in basic mode and not
configuration mode. To enter configuration mode, enter the
command. This command may be abbreviated to
config and it is also acceptable
terminal after, as a convenience for administrators familiar with
IOS who type it out of habit.
All of the following commands are equivalent:
tnsr# configure tnsr# configure terminal tnsr# config tnsr# conf t
After entering any one of the above commands, the prompt changes to reflect the new configuration mode:
tnsr# configure terminal tnsr(config)#
After entering other configuration commands, the new configuration is stored in the candidate database. A candidate database may be committed either when all of the required information is present, or when exiting the current context. Some commands are committed immediately.
exit command until the prompt returns to basic mode. At that
point, if no errors have been encountered by TNSR, all changes will have been
committed to the running database:
tnsr(config-interface)# exit tnsr(config)# exit tnsr#
Items are removed or negated using
no, for example, to remove an interface
tnsr(config)# interface GigabitEthernet0/14/1 tnsr(config-interface)# no description
If a change to the candidate database fails a validation check or application of the change to the system fails for some reason, it is discarded automatically by default. TNSR resets the candidate database to the current contents of the running database to avoid further attempts to apply the faulty configuration contained in the candidate database.
This automatic behavior can be changed, however, in cases where power users want more control to troubleshoot failed configuration transactions:
tnsr# configure tnsr(config)# no cli option auto-discard
When auto-discard is disabled, if a configuration commit fails the candidate database retains the faulty configuration data. Further configuration commands may apply additional changes to the candidate database. However, until the configuration data which caused the failure is removed or set to a value which can be successfully applied, no further commit will succeed.
Disabling the auto-discard feature only persists for the duration of the current CLI session in which it was disabled. At the start of a new CLI session, auto-discard will again be enabled by default.
A faulty candidate can be viewed with the
show configuration candidate
command, as described in Configuration Database
There are three approaches to rectify this situation:
Issue alternate commands that directly correct the faulty configuration.
Abandon the attempted configuration:
tnsr# configure tnsr(config)# configuration candidate discard
Removed the fault from the candidate configuration by reverting to the running configuration:
tnsr# configure tnsr(config)# configuration copy running candidate tnsr(config)# configuration candidate commit