Earlier this year, the Rayonism hackathon commenced to prototype the framework for Ethereum’s shift to proof of stake. This transition, frequently referred to as The Merge, will retain the current beacon chain (eth2) and execution layer (eth1) clients, and “combine” both chains by allowing the beacon chain to govern the execution layer’s consensus. This methodology is the latest in a succession of developments to the Ethereum roadmap (further details can be found here).
Although Rayonism demonstrated this to be a viable architecture, there remained numerous aspects to be designed, executed, and evaluated, including the actual transition from proof of work (PoW) to proof of stake (PoS). In order to facilitate this, client teams convened in person last week (similar to the Eth2 Interop from 2019) for a workshop dubbed Amphora 🏺.
Presented below is a summary of the primary achievements during the workshop, in addition to the roadmap leading to The Merge.
Amphora Milestones
The objective of the event was to enable the execution and consensus layer client teams to resolve outstanding challenges in the specifications and establish a series of development milestones. Each milestone advanced clients towards a fully operational merge devnet transitioning from PoW to PoS. Attending the workshop in person were representatives from Besu, Erigon, EthereumJS, Geth, Nethermind, Nimbus, Lighthouse, Lodestar, Quilt, and Teku. The Prysm team, alongside various members from the aforementioned teams, participated online.
The Amphora Milestones sought to firstly ensure that clients aligned with the specifications, then progressively introduce greater complexity while ultimately increasing the number of clients they could interoperate with.
The initial milestone, M1, only mandated clients to enact the merge specification. Most teams accomplished this even before the workshop commenced! To assist clients in confirming their implementations, several – testing – suites were made available.
Subsequently, milestones M2, M3, and M4 involved client teams establishing devnets with increasing technical intricacy and node variety. M2 required execution layer (EL) and consensus layer (CL) teams to collaborate one-on-one to launch a post-merge devnet. This confirmed that both layers could effectively communicate through the Engine API within a PoS framework.
M3 marked a progression from the Rayonism workshop: clients established ephemeral devnets that navigated the PoW to PoS transition.
The transition relied on PoW difficulty: once a block’s difficulty met or surpassed a designated threshold known as TERMINAL_TOTAL_DIFFICULTY, or TTD, it is deemed the final PoW block. The execution layer then commenced monitoring the PoS consensus layer for new blocks. To validate the robustness of each team’s implementation, EL teams were required to connect with two CL clients and vice versa to pass M3.
M4 represented the actual target of the event: to facilitate multiple EL & CL clients on a devnet that traversed the entirety of the PoW to PoS transition. In essence, while M3 focused on one-to-one devnets, M4 emphasized many-to-many interactions.
We accomplished this with a subset of the teams prior to the workshop’s conclusion, leading us to pursue our ambitious goal: M5.
Lasting Artifacts
This milestone aimed to evolve Amphora from a fleeting event into a long(er)-lived infrastructure available for community utilization. M5 necessitated client teams to initiate a devnet that would not only execute the entire transition with every combination of clients but would also endure beyond the Amphora event.
On the final day of the workshop, moments before the last dinner was served, M5 was reached: a network of 10,000 validators across 100 nodes and various client implementations launched under PoW, achieved the TERMINAL_TOTAL_DIFFICULTY, transitioned to PoS, and successfully finalized the chain 🎉!
The M5 devnet successfully finalizes post-merge, minutes before the workshop’s closing dinner. Photo by Ben Edgington.
Beyond Amphora
The achievements of Amphora generate significant momentum for The Merge. Client teams now have a definite list of tasks to tackle, and substantial progress has been made to engage with a broader segment of the Ethereum community.
Yesterday, a more stable iteration of the M5 Amphora devnet, Pithos, was introduced. With this network now operational (explorer here), anticipate public discussions on how developer tools and other essential Ethereum infrastructure can optimally prepare for the PoW to PoS transition.
Client teams and researchers will continue refining The Merge specifications to address issues identified during Amphora and act upon community feedback. In a few weeks, the specifications should be finalized, followed shortly thereafter by a new stable testnet being launched.
Thank you
The accomplishments during Amphora surpassed all expectations. For this, we extend our gratitude to the client teams and researchers, without whom none of the specifications would have been crafted or executed.
Furthermore, thanks to ConsenSys, Chainsafe and Ben Edgington for their outstanding coverage of the workshop.
