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] [-q] [--dry-run] [--snapshot [SNAPSHOT]] [-s SHOW [SHOW ...]] 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 -s SHOW [SHOW ...], --show SHOW [SHOW ...] Show command to execute on the device The rest of the arguments are passed to SSH or docker exec command
The –show option must be used after the host parameter, as the –show option consumes all arguments specified after it.
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_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_passto specify password (default: use SSH keys)
ansible_portto specify alternate SSH port (used primarily in VirtualBox environment)
netlab_show_command: command to execute when using
--showoption. Primarily used to deal with FRR/Cumulus Linux running
vtyshto execute show commands.
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.
Executing a Show Command¶
You can run netlab connect with –show args option to execute a show command on a lab device. In most cases, this is equivalent to running netlab connect host show args (see above), the major exceptions are FRR and Cumulus Linux.
For example, this is how you could execute show ip route command on Cumulus Linux or FRR container without worrying about the FRR
$ netlab connect r2 --show ip route Connecting to container clab-X-r2, executing sudo vtysh -c "show ip route" Use vtysh to connect to FRR daemon Codes: K - kernel route, C - connected, S - static, R - RIP, O - OSPF, I - IS-IS, B - BGP, E - EIGRP, N - NHRP, T - Table, v - VNC, V - VNC-Direct, A - Babel, D - SHARP, F - PBR, f - OpenFabric, > - selected route, * - FIB route, q - queued, r - rejected, b - backup t - trapped, o - offload failure O>* 10.0.0.1/32 [110/20] via 10.1.0.1, swp1, weight 1, 00:23:17 O 10.0.0.2/32 [110/0] is directly connected, lo, weight 1, 00:23:24 C>* 10.0.0.2/32 is directly connected, lo, 00:23:36 O 10.1.0.0/30 [110/10] is directly connected, swp1, weight 1, 00:23:24 C>* 10.1.0.0/30 is directly connected, swp1, 00:23:35
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.