Device Discovery Optional Arguments

optional_args on a scope entry is passed to the NAPALM driver. What a key does depends on how the driver reaches the device:

• SSH drivers, which is most of them: ios, iosxr, nxos_ssh, every *_ssh driver, the other CLI drivers, and eos with transport: ssh. They connect with Netmiko, which opens the SSH session with paramiko. NAPALM forwards every Netmiko connection argument it finds in optional_args, except the six it sets itself: ip, host, username, password, device_type and timeout. The keys in Connection settings work on every SSH driver.
• API and NETCONF drivers: nxos, eos over eAPI (its default), junos, iosxr_netconf, nokia_sros, aruba_aoscx, aruba_osswitch, cisco_asa and paloalto_panos. They read only their own keys: the custom drivers' under Driver-specific keys, the core drivers' in NAPALM's list. A key with a Netmiko name keeps the driver's meaning there: port is the API or NETCONF port on most of them, and junos also reads ssh_config_file, key_file and keepalive (30 by default), so jumphosts set up with ProxyCommand work with it too. Its NETCONF client ignores ProxyJump and connects directly, and so does iosxr_netconf's. The other Netmiko keys are ignored, except by iosxr_netconf (see iosxr_netconf).

Apart from iosxr_netconf, a key a driver does not know is ignored without a warning.

scope:
  - hostname: 192.0.2.10
    driver: ios
    username: admin
    password: ${DEVICE_PASSWORD}
    optional_args:
      ssh_config_file: /opt/orb/ssh-napalm.conf
      read_timeout_override: 30

Connection settings (SSH drivers)

These are the commonly useful ones. Any other argument of Netmiko's BaseConnection is forwarded the same way.

Timeouts

Netmiko waits 10 seconds for each command's output (iosxr waits the target's timeout, 60 seconds by default), so a device that answers more slowly can fail discovery with a read timeout. Raise the wait with read_timeout_override, as in the example above.

It replaces every read wait the driver uses, including the longer ones some drivers set for heavy commands, such as the 120 seconds hp_procurve allows for show running-config. A value below those shortens them. On iosxr it replaces the target's timeout too, so keep it above that, or raise timeout instead.

When it is the connection that is slow, for example through a jumphost, raise conn_timeout and banner_timeout together. conn_timeout bounds the whole handshake, banner included, and banner_timeout bounds the banner on its own, so raising only one gains a few seconds at most.

timeout has no effect inside optional_args on the SSH drivers: NAPALM drops it there. The target's own timeout, beside hostname, applies to most API and NETCONF drivers (not aruba_aoscx or paloalto_panos) and to iosxr as its per-command wait, but not to the other SSH drivers.

iosxr_netconf

iosxr_netconf reads port (830 by default), key_file, ssh_config_file, config_lock and config_encoding, and passes every other key to its NETCONF client, ncclient, which accepts only its own (such as hostkey_verify, look_for_keys, allow_agent and keepalive) and refuses the rest. timeout and most Netmiko keys, such as read_timeout_override, conn_timeout, banner_timeout, secret or use_keys, therefore stop it from connecting. By default it is one of the drivers tried when a target has no driver, so set driver on a target that uses those keys, or leave iosxr_netconf out of discovery_drivers.

Driver-specific keys

The core NAPALM drivers (ios, iosxr, iosxr_netconf, nxos, nxos_ssh, eos and junos) also take the keys in NAPALM's list, such as transport for eos and canonical_int for ios.