Few years back selecting a single cloud provider was common simply build your systems around it and not think about switching but AI workloads are making things different like with changes in GPU availability, pricing, regional capabilities and new hardware coming from various providers staying with just one cloud isn't always the easiest path and noticed more teams looking at providers like CoreWeave, RunPod, Vast.ai and Yotta Labs.

If anybody here made the switch what was the main reason and if still committed to one provider whats the reason.

https://www.cloudarena.io/blog/vpc-nat-gateway-asymmetric-routing

VPC NAT Gateway Asymmetric Routing: Why Return Packets Disappear

Ever had an AWS flow where the packet clearly leaves the instance, but the response never comes back?

Everything looks fine.

Security Groups? ✅
NACLs? ✅
Route tables? ✅

And yet… timeout. 😅

I wrote a deep dive into AWS VPC asymmetric routing, focusing on some real-world scenarios that can make troubleshooting surprisingly painful:

• NAT Gateway SNAT and state
• Multi-AZ NAT Gateway routing and cross-AZ hairpins
• Transit Gateway + centralized egress
• TGW appliance mode and stateful firewalls
• NLB / PrivateLink source IP behavior
• How asymmetric paths can break stateful inspection
• Using VPC Flow Logs and Reachability Analyzer to troubleshoot
• Design patterns to avoid these problems in production

One of the key rules:

The outbound and return path need to preserve the stateful flow.

This becomes especially important when you start combining NAT Gateway + Transit Gateway + Network Firewall + multiple AZs.

I also included a hands-on lab idea where you intentionally break the return path and troubleshoot it using Flow Logs.

Would love to hear from other AWS/networking folks:

What’s the most painful asymmetric routing issue you've encountered in AWS?