ToR switch VLAN Configurator Python Script
============================================

### Purpose ###
This script is used to create VLAN(s) on multiple Cisco ToR switch nodes to ensure consistency of VLAN configuration.

### Essential files in working directory ###
1. "vlan_configurator.py"
2. "device_hostname.txt"
3. "vlan_config.txt"

### Required Packages ###
1. Recommend to create virtual environment in your working directory. Then activate the venv and install packages.

  python3 -m venv net-env
  source net-env/bin/activate
  
2. Install netmiko package

  pip install netmiko
  
3. Verify require package has been installed

### Pre-conditions for script use ###
1. SSH access enabled on all Cisco nodes.
2. User must have a working credential to access the device (username & password).
3. The VLAN configuration commands to execute has been prepared (e.g., create VLANs)

### Running the Script ###
1. Activate python virtual environment on your working directory

  source net-env/bin/activate

2. Run the script
  
  python3 vlan_configurator.py
  
3. Once done running script, de-activate pythone venv

  deactivate


### Sample Run ###

(net-env) ruvasb@aklab:~/vlan_configurator$ python3 vlan_configurator_smart.py
Enter SSH username: cisco
Enter SSH password:

?? Connecting to 10.140.18.182 ...
? Connected to t-labsw-r501 (10.140.18.182)
? Creating VLAN 3901 on t-labsw-r501
configure terminal
Enter configuration commands, one per line.  End with CNTL/Z.
t-labsw-r501(config)#vlan 3901
t-labsw-r501(config-vlan)#name TEST_VLAN_A
t-labsw-r501(config-vlan)#end
t-labsw-r501#
? Creating VLAN 3902 on t-labsw-r501
configure terminal
Enter configuration commands, one per line.  End with CNTL/Z.
t-labsw-r501(config)#vlan 3902
t-labsw-r501(config-vlan)#name TEST_VLAN_B
t-labsw-r501(config-vlan)#end
t-labsw-r501#
? Creating VLAN 3903 on t-labsw-r501
configure terminal
Enter configuration commands, one per line.  End with CNTL/Z.
t-labsw-r501(config)#vlan 3903
t-labsw-r501(config-vlan)#name TEST_VLAN_C
t-labsw-r501(config-vlan)#end
t-labsw-r501#
?? Config saved on t-labsw-r501


?? Connecting to 10.140.18.183 ...
? Failed to configure 10.140.18.183: TCP connection to device failed.

Common causes of this problem are:
1. Incorrect hostname or IP address.
2. Wrong TCP port.
3. Intermediate firewall blocking access.

Device settings: cisco_ios 10.140.18.183:22



?? Connecting to 10.140.18.184 ...
? Connected to t-labsw-r503 (10.140.18.184)
? VLAN 3901 already exists on t-labsw-r503, skipping.
? VLAN 3902 already exists on t-labsw-r503, skipping.
? Creating VLAN 3903 on t-labsw-r503
configure terminal
Enter configuration commands, one per line.  End with CNTL/Z.
t-labsw-r503(config)#vlan 3903
t-labsw-r503(config-vlan)#name TEST_VLAN_C
t-labsw-r503(config-vlan)#end
t-labsw-r503#
?? Config saved on t-labsw-r503