How long does migrating to Google Cloud Application Load Balancer take?

Typically 4-12 weeks for mid-sized setups—discovery eats 1-2, testing/cutover the rest. Depends on bespoke rule count.

What if my load balancer has custom scripts Google doesn't support?

Use Service Extensions: Write in Go/Rust/C++, inject at edge. High-perf, but recode required—not 1:1.

Is Google Cloud Load Balancing cheaper than on-prem hardware?

Yes, for variable traffic—pay-per-use vs. CapEx. Watch add-ons like Armor.

5 Phases to Migrate On-Prem Load Balancers to Google Cloud ALB

Your ancient on-prem load balancer's humming along, riddled with custom scripts from a decade ago. Google Cloud promises a clean break to their Application Load Balancer—but is it really that simple, or just polished PR?

Dev Digest Apr 14, 2026 4 min read

Diagram of Google Cloud Application Load Balancer migration phases from on-prem hardware

⚡ Key Takeaways

Four-phase migration: Discovery, mapping, test, canary cutover—prioritize declarative over code. 𝕏
80% of rules map to ALB natives like URL maps; 20% need Service Extensions edge compute. 𝕏
Beware lock-in with custom extensions; hedge with OSS like Envoy. 𝕏
Real win: Scalability + cost savings, but audit rules first to nuke dead code. 𝕏