Part 2 — DevOps Concepts Every Network Engineer Should Know

Bridging the Mindset Gap

When software developers adopted DevOps, they made a conscious philosophical shift: treating infrastructure like software. This meant applying the same rigor, testing, and collaboration practices that worked for applications. Network engineers must make a similar mindset shift, but the principles are immediately relevant to network operations.

Infrastructure as Code (IaC): The Foundation

What IaC Actually Means: Instead of logging into devices and typing commands, you define your infrastructure in code files. A router configuration becomes a text file in Git. A firewall ruleset becomes declarative YAML. VLANs become data structures.

Why This Matters for Networks:

Before IaC, network documentation lived separately from reality. A network diagram might show VLAN 100 on the access layer, but the actual device might have VLAN 100 configured on the core layer due to forgotten change requests or incomplete implementations.

With IaC, the source code IS the truth. You git diff a configuration change the same way developers git diff application code. You can see exactly what changed, who changed it, when, and why.

IaC Benefits for Network Operations:

• Consistency Across Environments: Define a data center network layout once as code. Deploy it identically in production, disaster recovery, and test environments
• Repeatable Deployments: Building a new branch office network isn’t unique snowflake work; it’s running a playbook
• Version Control and Audit: Every change lives in Git with commit history. Compliance audits become trivial—you can prove exactly what was deployed when
• Disaster Recovery: Your entire network infrastructure definition is in code. Rebuild it in a different datacenter or cloud region by running the playbook again

CI/CD Pipelines Explained for Network People

Continuous Integration/Continuous Deployment (CI/CD) represents a fundamental shift in how changes reach production. Instead of submitting change requests, waiting for approvals, and manually implementing changes:

CI/CD Pipeline Flow:

1. Developer commits code → change is automatically tested
2. Automated tests pass → change is merged to main branch
3. Deployment triggered → infrastructure changes applied to production
4. Monitoring validates → system confirms change achieved intended outcome

This might seem risky for networks, but it’s actually safer than manual processes.

Why CI/CD Reduces Risk:

Traditional manual processes have a single failure point: the engineer implementing the change. If they’re tired, distracted, or don’t fully understand the network topology, mistakes happen. CI/CD removes human error through automation.

Pre-deployment validation checks catch configuration errors before they touch production. Post-deployment monitoring confirms the change worked.

If something breaks, automated rollback reverts the change in seconds. Compare this to traditional troubleshooting where operators spend hours identifying root cause.

Git and Version Control: Your Network’s Documentation System

Git transformed software development by making collaboration frictionless. Network engineers can apply the same benefits.

Network-Specific Git Benefits:

• Configuration History: Compare any two versions of a router config with git diff. See exactly what changed, line-by-line
• Rollback Capability: If a change breaks something, git revert rolls back to the previous version
• Blame and Accountability: git log shows who made changes and when, with commit messages explaining why
• Branching for Testing: Create a test branch, try experimental configurations, merge only when validated
• Collaboration: Multiple engineers can work on different config files simultaneously without overwriting each other’s work

Practical Git Workflow for Networks:

Engineer makes a change to router config → commits to feature branch → opens pull request → peer reviews changes → automated tests validate syntax → merge to main → CI/CD pipeline applies to production

This workflow catches mistakes in peer review before they touch production. Documentation (commit messages) is built in automatically.

Idempotency: The Secret to Safe Automation

Idempotency is perhaps the most important concept in network automation. An idempotent operation produces the same result whether you run it once or 100 times.

Example: Configuring an interface is idempotent. If you run an Ansible playbook configuring interface Gi0/0 with IP 192.168.1.1/24, it applies the config. If you run the exact same playbook again, it detects that the interface is already configured correctly and does nothing.

This is fundamentally different from imperative scripts that execute commands sequentially. Idempotent automation is safe to run repeatedly because it only makes changes if the current state differs from desired state.

Why This Matters:

You can run your entire network automation playbook daily without worrying it will break something that’s already correct. If a device reboots and loses a config, the playbook runs again and restores it. If someone makes a manual change and breaks something, the playbook detects the drift and fixes it.

Immutable vs Mutable Infrastructure

Traditional networking is mutable: you build a router, patch it, modify it, and update it over years. Each device becomes unique—a snowflake.

Immutable infrastructure means: when a change is needed, you don’t update the existing device. Instead, you provision a new device with the change and retire the old one.

For cloud networking, immutability is standard. For on-premises networks, it’s emerging through network virtualization. Either way, understanding immutability changes how you approach network design and automation.

Key Takeaway

DevOps mindset isn’t about coding skills—it’s about philosophy. It’s about treating infrastructure changes with the rigor of software development: version control, testing, peer review, and automated deployment. These practices reduce risk while accelerating change velocity.

Try this now: Put one device config in a Git repo and make a trivial change through a branch + PR workflow to practice the cycle.

Next: Part 3 — Essential tools you’ll use on day one.