Substrate genesis blocks not matching

Question

I am currently doing this tutorial. When I am following it as described and execute the alice and bob nodes both on the same machine it works as expected: the nodes are connecting and are creating and finalizing blocks. Now I want to get the same done but over the internet and on different machines. So I execute the bootnode on my PC and the other node on my Laptop. I compiled both from the same code and also forwarded the ports in my router. So now I expect the same behavior as when I am running both on my local machine. So when I execute them I see network traffic printed in both consoles but the bob node prints a warning: Bootnode with peer id '12D3KooWEyoppNCUx8Yx66oV9fJnriXwCcXwDDUA2kj6vnc6iDEp' is on a different chain (our genesis: 0xbfbd…3144 theirs: 0x8859…14c4) and they are not connected (Idle 0 peers).

So from the warning I conclude they have not the same genesis blocks which is obviously necessary to run as a blockchain. But from my understanding the joining node should copy the current state of the chain from the bootnode. How can I change bobs part to use alices state of the chain?

Both machines are running rust version 1.50.0

Thanks for your help!

Answer 1

Rust compilations are not deterministic, thus the exact same code for the exact same blockchain compiled on two computers will unfortunately not have the same genesis hash. (Specifically because part of the genesis of that chain is the Wasm Runtime blob, which is compiled non-deterministically with Rust).

You need to create a chainspec file to use for all other nodes. Note that you want to generate this on one computer, and pass the file to other nodes (don't re-generate it, as the genesis code will differ, as you ran into) before you then start other nodes using the correct chainspec and manually specifying boot nodes.