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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

usage: netlab connect [-h] [-v] [-q] [--dry-run] [--snapshot [SNAPSHOT]] host

Connect to a network device or an external tool

positional arguments:
  host                  Device or tool to connect to

options:
  -h, --help            show this help message and exit
  -v, --verbose         Verbose logging
  -q, --quiet           No logging
  --dry-run             Print the commands that would be executed, but do not execute them
  --snapshot [SNAPSHOT]
                        Transformed topology snapshot file

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

Collecting Device Data

netlab connect uses the lab snapshot file (default: netlab.snapshot.yml) to read device information. You can overwrite the default snapshot file with the --snapshot command line parameter.

Using Inventory Data

netlab connect command uses the following device data (most of it derived from device group_vars):

  • ansible_connection: Use docker exec if the connection is set to docker1. Use ssh if the connection is set to ssh, paramiko2, network_cli3 or netconf4. Fail for all other connection types.

  • 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.

If you want to process the results of the command executed on a lab device, use netlab connect -q to remove the “we are going to connect to device X” message.

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).

Warning

Do not use netlab connect in production environment.

1

FRR and Linux devices running under containerlab

2

Linux virtual machines, including Cumulus VX and Nokia SR Linux.

3

Devices with traditional networking CLI, including Cisco IOSv, Cisco IOS-XE, Cisco Nexus OS, and Arista EOS.

4

Junos