Migrating from Legacy Network to VPC Network with Minimal Downtime: Seeking Advice and Shared Experi

[EranB]

Hey everyone,

I'm part of a team migrating our infrastructure from a Legacy Network to a VPC Network. Given the critical nature of our services, we're exploring ways to execute this with the least possible downtime. Our current strategy involves setting up a VPN between the Legacy and VPC networks to facilitate a gradual migration of VMs, moving them one at a time to ensure stability and minimize service disruption.

Has anyone here gone through a similar migration process? I'm particularly interested in:

1. Your overall experience: Do you think the VPN approach is practical? Are there any pitfalls or challenges we should be aware of?

2. Downtime: How did you manage to minimize downtime? Was live migration feasible, or did you have to schedule maintenance windows?

3. Tooling and Strategies: Are there specific tools or strategies you'd recommend for managing the migration smoothly? Would you happen to have any automation tips?

4. Post-migration: After moving to a VPC, have any surprises or issues cropped up? How did you mitigate them?

I aim to balance minimizing operational risk and ensuring a smooth transition. I'd greatly appreciate any insights, advice, or anecdotes you can share from your experiences. I am looking forward to learning from the community!

UPDATE:
We want to migrate to the new VPC network in-order to use GKE (k8s) in the same network.

[Rfelizardo]

Hi @EranB,

Welcome to the Google Cloud Community!

If your purpose is to convert Legacy Network to a VPC Network, you may want to consider checking out this documentation. Using this tool can convert your Legacy network to a VPC network without any network disruption as your resources continue to operate seamlessly. If the network conversion encounters an error, it will automatically roll back.

Using the VPN approach is possible but it would be best to take in to consideration that this would incur additional cost. Additionally, review the best strategies and practices to implement when migrating.

Hope you find this information helpful. Thank you

[EranB]

Hi,

Thank you for the information and for welcoming me to the Google Cloud Community!

I'm considering the VPN approach for the conversion of our Legacy Network to a VPC Network. Given the importance of minimal downtime for our operations, we plan to have the VPN active only for a couple of hours. Could you provide an estimate of the costs involved, assuming about 50GB of data transfer? I would expect this to be around $100, but please correct me if I'm wrong.

Additionally, I have a few queries:

1. Can we view the migration tool's source code? Understanding its workings will help us evaluate its reliability and security.
2. Does this tool simply change the current instance's network settings?
3. What is the typical latency when using this VPN? This information is crucial since our operations are sensitive to delays.
4. How can I set up such a VPN?

Please note that all our operations are confined to a single region, which should simplify the setup.

Looking forward to your guidance on these points.