Connecting to Lab Devices

netlab connect command uses information stored in Ansible inventory and reported by ansible-inventory command to connect to a lab device using SSH or docker exec. You could use it with an inventory file created with netlab create command or with any other Ansible inventory.


usage: netlab connect [-h] [-v] host

Connect to a network device

positional arguments:
  host           Device to connect to

optional arguments:
  -h, --help     show this help message and exit
  -v, --verbose  Verbose logging
  -d, --devices  Use netsim-devices.yml as inventory source

The rest of the arguments are passed to SSH or docker exec command

Collecting Inventory Data

When run with --devices argument, netlab connect reads inventory data from netsim-devices.yml file1. You can override the default file name with NETSIM_DEVICES environment variable.

In all other cases, netlab connect uses ansible-inventory command to fetch device data from Ansible inventory.

Using Inventory Data

netlab connect command uses the following device inventory variables:

  • ansible_connection: use docker exec instead of ssh if the connection is set to docker

  • ansible_host: IP address or alternate FQDN for the lab device (default: host name specified on the command line)

  • ansible_user: remote username for SSH session (default: not specified)

  • ansible_ssh_pass to specify password (default: use SSH keys)

  • ansible_port to specify alternate SSH port (used primarily in VirtualBox environment)

Executing a Single Command

Command line parameters specified after the device name are passed to ssh or docker exec command, allowing you to execute a single command on a lab device.

Handling SSH Keys

netlab connect command disables SSH host key checking and uses /dev/null as known hosts file to simplify lab connectivity (some virtual devices change SSH key on every restart).


Do not use netlab connect in production environment.


netsim-devices.yml inventory uses Ansible naming convention and contains information very similar to what ansible-inventory would return.