you have 2 Options.
1. You can run EEM Script inside the device and push the config to TFTP Server.
2. you can have simple Linux script can get in each device and push the config to TFTP Server.
or simple tool Solarwinds Cattools does everything for you auto back all devices.
https://documentation.solarwinds.com/en/Success_Center/KCT/Content/KCT_AG_CatTools_Overview.htm
EEM Script example :
Supposed you need to back up your router configuration at a specific time every day, you can do this automatically using EEM.
If you are good with Linux you understand Cron command.
event manager environment filename 2900-1-confg
event manager environment tftploc tftp://192.168.1.101/
event manager applet backupcfg
event timer cron name job1 cron-entry “34 2 * * 0-6″
action 1.0 cli command “enable”
action 2.0 cli command “conf t”
action 3.0 cli command “file prompt quiet”
action 4.0 cli command “end”
action 5.0 cli command “copy start $tftploc$filename”
action 6.0 cli command “conf t”
action 7.0 cli command “no file prompt quiet”
Linus script for backup using pythpn.
http://www.techspacekh.com/automate-backup-cisco-router-switch-configuration-with-python-script/
