---
tags: eth2devs
description: Notes from the regular proof of stake [Eth2] implementers call
image: https://benjaminion.xyz/f/favicon-96x96.png
---
# PoS Implementers’ Call #77 - 2021-12-02
[Quick contemporaneous notes by Ben Edgington; fka "Eth2 Implementers' Call"]
Agenda: https://github.com/ethereum/pm/issues/429
Livestream: https://youtu.be/1fIg_t6hZ8U
## Intro
Note: Arrow Glacier hard fork on Eth1 next Wednesday: update your Eth1 nodes!!
Updates to consensus layer specs: [v1.1.6](https://github.com/ethereum/consensus-specs/releases) - fork choice fixes are in.
## Kintsugi office hours
v3 of the Merge specs just released. Validation errors are more expressive. Minor updates to Eth1 EIPs. Engine API update to alpha.5. Devnet-3 will target these specs.
Marius has been organising mass Merge testing :raised_hands:
### Merge-devnet-2
Devnet-0 was broken by running two sister blocks with TTD. Half of consensus clients chose one; half the other. We need to be able to handle this, and be able to override the terminal PoW block hash as well on the consensus layer. [Mikhail] The first PoS block proposer should sort this out - the network should not split over this. However, something went wrong... It's still running and is available for a post-mortem.
Devnet-1 had a bug in Geth.
Devnet-2 is running well. Hit TTD and switched to PoS 2 days ago. Making deposits for new validators is fine, and lots of testers are sending Txs. Things looking fine. Teku joined and is proposing as of yesterday. Lighthouse has a majority, other clients allocated 5% each for now. No blocker to making this equal between clients.
Marius got all 5 consensus clients working with Geth to follow the chain.
Teku--Nethermind is not working currently - Nethermind to investigate.
Devnet-3 next week will target v3 specs.
Kintsugi testnet launch targeted for the 14th, and plan is to run it for a longer period of time.
### Updates
**Nethermind**
Devops team is writing some docs on how to run with various consensus clients. Also testing merge MEV plug-in. Fixing interop with Teku and Nimbus.
**Lighthouse**
Merged Kintsugi into "unstable" branch today; should migrate to "stable" in a couple of weeks.
### Discussion
[Mikhail] [Proposal](https://github.com/ethereum/execution-apis/issues/137) to add `engine_getBlockBodies` bodies to API. This can be used to de-duplicate the blocks between layers - the Eth1 payloads could be stored only on the execution client side, and the consensus client would fetch (and store) them as necessary.
[AdrianS] What would happen if the execution client is offline? [Mikhail] You would be unable to serve blocks to other clients. This might result in being downscored in gossip, but that's likely not your biggest problem at this stage.
[Mikhail] Optimistic sync: what should a validator do while the sync is in progress? Is it allowed to attest while syncing? Probably should not be attesting in this case. See [this issue](https://github.com/ethereum/consensus-specs/issues/2735.) [Alex] Feels like validators should wait until fully synced, otherwise we are in "lazy validator" territory. [Mikhail] If a block is fully verified, it _might_ make sense to attest to it, and it has some value for FFG, but might open other issues: need to analyse how it affects safety and liveness if we allow it.
[Mikhail] [transition edge case scenario](https://github.com/ethereum/consensus-specs/issues/2636#issuecomment-960647404). Some execution clients might have changed their fork choice to PoS. Should they be switched back? Recommend not. **Action** please review the issue and add any thoughts. Mikhail plans to close it next week.
[Dustin] has been looking at optimistic sync. Current [descriptions](https://hackmd.io/Ic7VpkY3SkKGgYLg2p9pMg#Implementation-requirements) mix general properties and specific implementation details. Would like to see a cleaner separation of concerns around: (1) explanatory material, (2) spec requirements, and (3) implementation details.
[Marius] Noticed when switching between consensus clients, they all try to import all the blocks again (leading to re-execution on the execution layer). Optimistic sync should fix this. Please test opt syncing not only from beginning, and also when switching consensus client. [Mikhail] This should all work out fine. [Marius] Could memoise the execution of the block hash to avoid the overhead.
## Spec discussion and AOB
[Hsiao-Wei] There has been [a fix](https://github.com/ethereum/consensus-specs/pull/2760) to the proposer boost score. This will be in the next spec release (not in the recent one).
[Leo] Want to continue to increase the number of standard metrics across clients. Currently eight are well supported. Will continue discussions with client teams.
[Tim] [Call next week](https://github.com/ethereum/pm/issues/423) around MEV in Eth2 - review of FlashBots' proposal.
[Pooja] PEEPanEIP planning to have a call to explain Merge testnet setup, and another with Mikhail on RANDOM opcode EIP during December (sorry, not swift enough to catch the dates).
[Trent] tomorrow is the [Merge Community call](https://github.com/ethereum/pm/issues/419).
[Hsiao-Wei] Naming! Opened [an issue](https://github.com/ethereum/pm/issues/430). Consensus on consensus upgrades is star names; uncertain for execution upgrades. Looking for name starting with "B". Please nominate candidates in the issue. Deadline Dec 13th. Can choose top four and put it to a community vote (as we did for Altair). Or we could just decide in the next call. [Tim] suggest separate breakout room to discuss naming things rather than this call. Also can do async.
* * *
# Chat highlights
From stokes to Everyone 02:07 PM
: https://hackmd.io/@n0ble/kintsugi-spec
From parithosh to Everyone 02:19 PM
: If anyone wants to start validating from genesis in devnet-3, please do let me know
From Mikhail Kalinin to Everyone 02:22 PM
: https://github.com/ethereum/execution-apis/issues/137
From Mikhail Kalinin to Everyone 02:30 PM
: https://github.com/ethereum/consensus-specs/issues/2735
https://github.com/ethereum/consensus-specs/issues/2636#issuecomment-960647404
From Dustin Brody to Everyone 02:37 PM
: https://hackmd.io/Ic7VpkY3SkKGgYLg2p9pMg#Implementation-requirements
From Hsiao-Wei Wang to Everyone 02:44 PM
: naming discussion: https://github.com/ethereum/pm/issues/430
From protolambda to Everyone 02:47 PM
: @Marius The replay of blocks you are seeing on start-up might just be the last 2 epochs, some CLs don't persist the unfinalized part in their state db, and instead apply the blocks again.
From Hsiao-Wei Wang to Everyone 02:50 PM
: https://github.com/ethereum/consensus-specs/pull/2760
^^^^ fork-choice proposer boost score bugfix
From Tim Beiko to Everyone 02:53 PM
: https://github.com/ethereum/pm/issues/423
From Trenton Van Epps to Everyone 02:53 PM
: tomorrow is the Merge Community call
https://github.com/ethereum/pm/issues/419
1400 UTC, 9 EST
From Mikhail Kalinin to Everyone 03:00 PM
: CL-EL = Star-City after the merge makes sense to me, as there could be pure CL and pure EL upgrades. Having different naming conventions to distinguish the two is good