We solved container networking at massive scale (and you can learn how) 🚀

Ever wondered how we manage networking for tens of thousands of containers without breaking a sweat? 🤔

Traditional networking approaches fall apart when you're dealing with high-density containers that are constantly being created, destroyed, and moved around. Centralized systems become bottlenecks, and suddenly your infrastructure is more fragile than a house of cards.

So we built something different: a stateless mesh networking system that embeds routing information directly into IP addresses. No databases, no control planes, no drama. ✨

Here's what we achieved:

• 8,192 containers per VM (yes, you read that right!)
• Zero network bottlenecks through direct VM-to-VM communication
• Instant service discovery - new containers become routable immediately
• Predictable performance that scales with your infrastructure

The secret sauce? We borrowed inspiration from IPv6's IPv4-mapped addresses and embedded VM information right into the container IP addresses. When a packet needs routing, our custom ARP daemon extracts the target VM's IP from the destination address and creates direct point-to-point connections.

Our latest deep-dive article walks you through the entire technical implementation, from the initial challenges to the creative solutions we found in "reserved for future use" IPv4 space.

This is why your Upsun preview environments spin up in minutes, not hours. The networking just works - invisibly and instantly. 💪