Juniper Network Automation: Ansible, PyEZ, JSNAPy, and SaltStack

Juniper Network Automation: Ansible, PyEZ, JSNAPy, and SaltStack

In modern networking, automation is a requirement.
Juniper’s ecosystem provides mature tools to reduce manual effort, minimize errors, validate intent, and accelerate delivery.

Table of Contents

• 1. Ansible juniper.device Collection
• 2. PyEZ
• 3. JSNAPy
• 4. SaltStack
• 5. Comparison Matrix
• 6. When to Use Which Tool
• 7. Sample End-to-End Pipeline
• 8. Summary

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1. Ansible juniper.device Collection

Official Ansible collection for Junos (agentless, NETCONF or local execution).

Docs: https://ansible-juniper-collection.readthedocs.io/

Key Capabilities

• Facts collection (system / RE / chassis)
• Config load (merge / replace / set), diff & commit
• Operational CLI commands
• NETCONF RPC execution
• JSNAPy test invocation
• Software image upgrades
• Local (on-box) PyEZ path or remote NETCONF

Installation

ansible-galaxy collection install juniper.device
pip install junos-eznc ncclient

Inventory (INI)

[junos_devices]
router1 ansible_host=192.0.2.1
router2 ansible_host=192.0.2.2

[junos_devices:vars]
ansible_user=netadmin
ansible_password=juniper123
ansible_connection=local
ansible_python_interpreter=/usr/bin/python3

Example: Gather Facts

---
- name: Gather Junos facts
  hosts: junos_devices
  gather_facts: no
  collections:
    - juniper.device
  tasks:
    - name: Retrieve facts
      juniper.device.facts:
      register: facts_output

    - name: Show facts
      debug:
        var: facts_output

Notable Modules

Module	Purpose
facts	Gather system / RE / chassis facts
config	Load, diff, commit configurations
command	Run CLI operational commands
rpc	Execute NETCONF RPCs
jsnapy	Run JSNAPy validation suites
software	Manage Junos OS upgrades
ping	Test reachability from the device

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2. PyEZ

Python library (junos-eznc) for programmatic Junos interaction; best for custom logic.

Features

• Open NETCONF session (Device)
• Structured facts access
• Invoke RPCs (XML / JSON)
• Load / compare / commit configs (Config)
• Table/View abstraction for structured data
• Embed in Python services / CI tooling

Install

pip install junos-eznc

Example

from jnpr.junos import Device
from jnpr.junos.utils.config import Config

dev = Device(host='192.0.2.1', user='netadmin', password='juniper123')
dev.open()
print(dev.facts)
with Config(dev, mode='exclusive') as cu:
    cu.load('set system host-name demo-router', format='set')
    if cu.diff():
        cu.commit()
dev.close()

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3. JSNAPy

State validation & snapshot comparison framework.

Use Cases

• Pre / post change validation
• Compliance & golden-state checks
• Regression testing
• Intent assurance

Install

pip install jsnapy

Workflow

1. Define tests (e.g. test_bgp.yml)
2. Pre-change snapshot:

   jsnapy --snap pre_change -f test_bgp.yml -t hosts.yml
   

3. Apply changes
4. Post-change snapshot + compare:

   jsnapy --check pre_change post_change -f test_bgp.yml -t hosts.yml
   

Sample Test (Excerpt)

tests:
  - test_bgp_neighbors:
      rpc: get-bgp-summary-information
      iterate:
        id: peer-address
        xpath: //bgp-peer
        tests:
          - is-equal: peer-state, Established

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4. SaltStack

Event-driven automation & orchestration using Junos proxy minions.

Strengths

• Real-time reactor (event -> action)
• Scales to many devices centrally
• Declarative state enforcement
• Extensible modules & returners

Minimal Libraries

pip install junos-eznc jxmlease

Example

salt 'router1' junos.cli "show version"

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5. Comparison Matrix

Aspect	Ansible (juniper.device)	PyEZ	JSNAPy	SaltStack
Style	Declarative playbooks	Imperative Python	Validation snapshots	Event / state driven
Transport	NETCONF / local	NETCONF	NETCONF	NETCONF via proxy
Best For	Multi-step workflows	Custom tooling	Intent & state validation	Real-time orchestration
Learning Curve	Low–Medium	Medium	Low	Medium–High
Diff Support	Config diff built-in	Manual (script)	Snapshot comparison	State reports
Multi-Vendor	Yes	No	Limited (Junos focus)	Limited (focus on managed types)
Extensibility	Roles / collections	Full Python	YAML tests	Modules / reactors / engines
CI/CD Integration	Common	Common	Validation stage	Possible (extra setup)
Event Handling	Indirect	Scripted	None (batch)	Native

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6. When to Use Which Tool

Goal	Recommended Tool
Fast repeatable config rollout	Ansible
Deep custom device logic	PyEZ
Pre/post change assurance	JSNAPy
Event-triggered remediation	SaltStack
Unified multi-vendor automation	Ansible
Python service integration	PyEZ
Compliance & drift detection	JSNAPy (+ Ansible)
Large scale realtime orchestration	SaltStack

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7. Sample End-to-End Pipeline

1. JSNAPy: pre-change validation
2. Ansible: deploy config (juniper.device.config)
3. JSNAPy: post-change comparison (intent confirmation)
4. PyEZ: custom inventory export or complex logic
5. SaltStack: reactor watches for anomalies & triggers rollback / alert

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8. Summary

Use each where it excels:

• Ansible: orchestration & standardized config
• PyEZ: granular programmable control
• JSNAPy: confidence & compliance validation
• SaltStack: scale & event-driven operations

Combined they form a robust Junos automation toolchain.