Nornir connection plugin for SRLinux
Project description
nornir-srl
This module provides a Nornir connection plugin for Nokia SRLinux devices. It uses the gNMI management interface of SRLinux to fetch state and push configurations and the PyGNMI Python module to interact with gNMI.
Rather than limiting the connection plugin to primitives like open_connection
, close_connection
, get
, set
, etc, this module provides also methods to get information from the device for common resources. Since the device model tends to change between releases, it was considered a better approach to provide this functionality as part of the connection plugin and hide complexity of model changes to the user or Nornir tasks.
In addition to the connection plugin, there is a set of Nornir tasks that use the connection plugin to perform common operations on the device, like get BGP peers, get MAC table, get subinterfaces, etc. These Nornir tasks are called by a command-line interface fcli
that provides a network-wide CLI to perform show commands across an entire set or subset for SRLinux nodes.
The current functionality is focused on a read-only network-wide CLI to perform show commands across an entire set or subset for SRLinux nodes, as defined in the Nornir inventory and through command-line filter options. It shows output in a tabular format for easy reading. Following versions may focus on configuration management and command execution on the nodes.
Installation
Docker-based installation
This is the easiest way to get started. It requires Docker and optionally Containerlab to be installed on your system.
NOTE: if you have issues connecting to the docker network of containerlab, make sure proper
iptables
rules are in place to permit incomming traffic on the docker network interface. For example, on Ubuntu 20.04, you can use the following command:
iptables -I DOCKER-USER -o docker0 -j ACCEPT -m comment --comment "allow inter-network comms"
To run fcli, create an alias in your shell profile, for example, assuming that you have a clab_topo.yml
file in your current directory and lab is up and running:
CLAB_TOPO=clab_topo.yml alias fcli="docker run -t --rm -v /etc/hosts:/etc/hosts:ro -v ${PWD}/${CLAB_TOPO}:/topo.yml wdesmedt/srl-fcli -t /topo.yml"
To run a report, specify the report name as the first argument to the alias, for example:
fcli sys-info # for system information like NOS version, uptime, etc
fcli bgp-peers # for BGP peers
Python-based installation with pip
Create a Python virtual-env using your favorite workflow, For example:
mkdir nornir-srl && cd nornir-srl
python3 -m venv .venv
source .venv/bin/activate
Following command will install the the nornir_srl
module and all its dependencies, including Nornir core.
pip install wheel
pip install -U nornir-srl
Use
Currently, only the network-wide report functionality is supported via the fcli
command
$ fcli --help
Usage: fcli [OPTIONS] REPORT
Options:
-c, --cfg TEXT Nornir config file [default: nornir_config.yaml]
-i, --inv-filter TEXT filter inventory, e.g. -i site=lab -i role=leaf
-f, --field-filter TEXT filter fields with <field-name>=<glob-pattern>,
e.g. -f state=up -f admin_state="ena*"
-b, --box-type TEXT box type of printed table, e.g. -b
minimal_double_head. 'python -m rich.box' for
options
-r, --report-options TEXT report-specific options, e.g. -o route_fam=evpn
-o route_type=2 for 'bgp-rib report
-t, --topo-file TEXT CLAB topology file, e.g. -t topo.yaml
--cert-file TEXT CLAB certificate file, e.g. -c ca-root.pem
--help Show this message and exit.
REPORT
is a mandatory argument and specifies the report to run. To know which reports are supported, specify a dummy report name:
$ fcli test
Report test not found. Available reports: ['bgp-peers', 'subinterface', 'ipv4-rib', 'mac-table', 'sys-info', 'nwi-itfs', 'lldp-nbrs']
Nornir-based inventory mode
In this mode, a Nornir configuration file must be provided with the -c
option. The Nornir inventory is polulated by the InventoryPlugin
and associated options as specified in the config file. See below for an example with the included YAMLInventory
plugin and the associated inventory files.
Create the Nornir confguration file, for example:
# nornir_config.yaml
inventory:
# plugin: SimpleInventory
plugin: YAMLInventory
options:
host_file: "./inventory/hosts.yaml"
group_file: "./inventory/groups.yaml"
defaults_file: "./inventory/defaults.yaml"
runner:
plugin: threaded
options:
num_workers: 20
Create the inventory files as referenced in the above configuration file, for example:
## hosts.yaml
clab-4l2s-l1:
hostname: clab-4l2s-l1
groups: [srl, fabric, leafs]
clab-4l2s-l2:
hostname: clab-4l2s-l2
groups: [srl, fabric, leafs]
clab-4l2s-s1:
hostname: clab-4l2s-s1
groups: [srl, fabric, spines]
## groups.yaml
global:
data:
domain: clab
srl:
connection_options:
srlinux:
port: 57400
username: admin
password: admin
extras:
path_cert: "./root-ca.pem"
spines:
groups: [ global ]
data:
role: spine
type: ixr-d3
leafs:
groups: [ global ]
data:
role: leaf
type: ixr-d2
The root certificate is specified once for all devices in group srl
via the connection_options.srlinux.extras.path_cert
parameter.
This mode is used for real hardware-based fabric.
CLAB-based inventory mode
In this mode, the Nornir inventory is populated by a containerlab topology file and no further configuration files are needed. The containerlab topo file is specified with the -t
option.
fcli
converts the topology file to a hosts and groups file and only nodes of kind=srl are populated in the host inventory. Furthermore, the prefix
parameter in the topo file is considered to generate the hostnames. The presence of labels in the topo file is mapped into node-specific attribs that can be used in inventory filters (-i
option).
Filtering
Filtering
Optionally, you can specify filters to control the output. There are 2 types of filters:
- inventory filters, specified with the
-i
option, filter on the inventory, e.g.-i hostname=clab-4l2s-l1
or-i role=leaf
based on inventory data - field filters, specified with the
-f
option. This filters based on the fields shown in the report and a glob pattern, e.g.-f state="esta*"
. Multiple field filters can be specified by repeated-f
options - report-specific options are options specific to a report, if applicable. Currently, the only report that needs extra arguments is 'bgp-rib', i.e.
route_fam=evpn|ipv4|ipv6
androute_type=1|2|3|4|5
. The latter relates to EVPN route-trypes and is optional. Defaults to '2' (mac-ip-routes).
Demo
Prerequisites
- Containerlab binary installed
nornir-srl
installed as described above:pip install -U nornir-srl
in a Python virtual-env- sufficient resources to run 8 SRLinux containers
- big screen estate to show the output (or small font size)
Run the demo
clone the nornir-srl
repo and cd into the demo
folder
git clone https://github.com/srl-labs/nornir-srl.git
cd nornir-srl/demo
./run_demo.sh
It will spin up a 6-node SRLinux fabric and run all the available fcli
reports sequentially.
Remove the lab with clab destroy -t demo.clab.yaml
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