In this post series, we will cover one of the wonderful things with Junos, which is loading configurations to the devices. Compared to other vendors where you paste into a live configuration, Junus uses a candidate configuration for all changes. A great benefit of this is that there are a few ways to load configurations onto the devices.
The ways we can load the configurations are shown below.
factory-default Override existing configuration with factory default
merge Merge contents with existing configuration
override Override existing configuration
patch Load patch file into configuration
replace Replace configuration data
set Execute set of commands on existing configuration
update Update existing configuration
I want to briefly touch on a few of the commands.
The first command, factory-default, is a way to soft reset the configuration back to the factory configuration without losing any of the locally stored data. The alternate way is factory default the configuration is to use the request system zeroize command. The zerioze command will rest the device back to the factory configuration and remove all locally stored user data (logs, files, etc).
The second command, override, will discard the current configuration and replace it with what you load into the device. When doing this the Junos device will re-evaluate the entire configuration you have entered. By re-evaluating the config, it will treat everything like it is new and you will have an impact to the device. If you want to just update the config and not re-evaluate everything, then you would use load update, which we will cover in post 4.
For this post, we will cover merge, patch, replace, update, and set.