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· 4 min read
Damian Nadales

Consensus Quarterly Update​

2022-12 - 2023-01​

Main achievements​

UTxO HD​

The prototype is feature complete and thoroughly tested at the consensus level. In particular, we invested a lot of time in writing property-test for the mempool, and other crucial new parts of the prototype. Now we are ready to run integration tests and system-level benchmarks.

Genesis​

We identified and fixed a slowdown in cross-era forecasting that was inhibiting our efforts to benchmark the ChainSync Jumping prototype. This resulted in a 7% speedup in full sync times in the baseline.

We also started prototyping a self-contained implementation of the Genesis dynamics (in particular of the parts intentionally not part of the ChainSync Jumping prototype) that furthered our understanding of subtleties and edge cases.

Support​

  • We worked on designing integration of new VRF and KES crypto into consensus.
    • Crypto class was split into two parts: Crypto and HeaderCrypto.
    • With the Ledger team's help, we refactored cardano-ledger to use a proxy type for VRF.

Conway era​

  • PR went through its second review round. It is about to be merged, but it got delayed due to people's availability during Christmas break.

Technical debt​

  • We improved the capabilities of our io-sim library, which is key for testing and simulating Cardano components.
  • We removed thunks from epoch translations in the ledger, which is important for reducing memory consumption of the Cardano node.

Fostering collaboration​

  • We added a tutorial on how to instantiate the Consensus layer to run custom ledgers. This should be a valuable resource to people looking to roll their own custom blockchain (either for commercial or research purposes).
  • We added an overview of consensus to the top level documentation of ouroboros-network. This overview describes the consensus components and adds a hyperlinked map to the modules documentation.

Next steps​

UTxO HD​

  • Evaluate the extensibility of the prototype. Moving the UTxO to disk is only the first step towards reducing the memory requirements of Cardano node, and ensuring its long term sustainability. In the future, we plan on moving other large maps, such as delegation maps. The prototype should be able to accommodate these changes without any major modifications.
  • Start the integration with other downstream components, such as the wallet and db-sync. The idea is to identify and address any potential pain points that might arise during this integration.
  • Run integration tests and system-level benchmarks.

Genesis​

  • Finish benchmarking and tuning the fast-path ChainSync Jumping prototype
  • Expand and optimize the self-contained implementation of the Disconnect Rule (including density comparisons and the LoE)
  • Develop documentation and smoke tests for these components.
  • Start modifying the ChainSync Client for the LoP and LoR.

Support​

  • Help the Network team with diagnosing performance regression in block production.

Tech debt​

  • Fix property-test failures concerning iterators (#3999 and #4183).

Fostering collaboration​

Risks​

UTxO HD​

  • Moving other parts of the ledger state to disk might require a major redesign of the prototype. For instance, if it turns out that the epoch change rules require access to the full ledger state. If this is the case, we might accept this risk and do the redesign after the initial release of UTxO-HD.
  • Integration with downstream clients might require more work than we anticipate.
  • Access to the benchmarking's team time and resources.
  • Benchmarking results might show significant performance degradation, which will require additional work if such performance degradation is not accepted by other stakeholders.
  • The prototype's performance might not be accepted by other stakeholders. Here we need to clearly communicate that this is necessary to ensure that as the blockchain size grows, the node can operate within reasonable memory constraints.

· 5 min read
Marcin Szamotulski

Network Quarterly Update​

2022-11 - 2023-01​

Summary​

The primary goal of the networking team was to focus on the single relay release of P2P. We fixed a number of small late bugs, and concluded QA & performance testing. Although it was discovered a regression in performance of block production when P2P is enabled, relaying with P2P performs better comparing to a non p2p. We concluded that this is not a blocker for the Single Relay Release which is planned shortly.

Peer sharing has gone through review and final review is just being done right now. After merging it will still be disabled (hidden behind a flag) as it's not safe without eclipse evasion. We started implementing light peer sharing (i.e. include inbound peers into known peer set of the outbound governor).

We started a detailed eclipse evasion design, it will continue in the next quarter.

We also made a major revision of package structure of the network packages. We ended up with a very clean dependency graph (pr #4155).

Armando Santos delivered a talk at the ODOPIS 2022 conference on principles of distributed systems in Brussels. The slides are available here.

Neil Davies gave an invited seminar on DeltaQ at Université Catholique de Louvain.

We also found and fixed a few of bugs:

  • a bug in keep alive mini-protocol which resulted in warm to cold transitions to be always executed through a timeout path rather than do a clean demotion ([pr #4168]).

  • fixed an assetion failure in the outbound governor (issue #4177)

Next steps​

We will work towards the next release of P2P for block producer nodes. This includes:

  • analysing performance regression for BP nodes when using P2P
  • finish the work on controlling the block forger through node kernel (pr #3800)
  • address issue #3907 and write a script to analyse deployment of P2P relays

We would like also to push forward eclipse evasion. Although most of the work has be done already the release of io-sim on Hackage will happen in the next quarter.

We would also like to address chain-sync timeout issue recently diagnosed by Karl Knutsson.

If time permits we would also like to address some technical debt, especially:

Risks​

The performance regression for block producer with P2P needs to be investigated in the near future. This is blocker for the release of P2P on BP nodes.

Detailed log​

Contributions to Ouroboros-Network​

  • We added TraceDemoteLocalAsynchronous, which enables notification of critical issues for SPOs
  • We fixed cardano-ping compatibility with NodeToNodeV_10 (P2P, pr #4165)
  • We fixed a bug in demotion peers to cold which affected P2P nodes (commit-61058aa5c2)
  • Karl Knutsson enhanced SendFetchRequest (commit-bb1c3dddee), open-source contribution)
  • We turned SizeInBytes into a newtype.
  • We extended CONTRIBUTING.md, README.md, added CODE_OF_CONDUCT.
  • We fixed DNS test failure issue #4191
  • We fixed a simulation bug found in issue #4258
  • [pr #4168]
  • issue #4177

Contributions to Cardano-Node​

  • We maintained the Single Relay Release pr #4612, (e.g. fixing CI issues, Rebasing it when necessary, publishing packages to Cardano Haskell Packages);
  • We enhanced JSON serialisation / deserialisation of NodeToNodeVersion and NodeToClientVersion;

Contributions to IOSim​

  • We started to use Cardano Haskell Packages for IOSim (pr #48)
  • We updated change log files
  • We added support of ghc-9.4 (pr #50)

We also addressed the following issues in pr #57 in order to prepare the package for publication on Hackage:

  • refactored io-classes timers API (issue #46);
  • created a new package si-timers which exposes an interface using SI units and is safe on 32-bit systems (issue #59);
  • added monad transformers instances for classes defined in io-classes (issue #58);
  • created io-classes-mtl package which includes (experimental) instances for monad transformers;
  • provide MonadMonotonicTimeNSec in io-classes and MonadMonotonicTime in si-timers (so that io-classes follow the base package);
  • added registerCancellableDelay in si-timers (which allowed us to hide fancy timer api and clean io-classes)
  • added support for js_HOST_ARCH (the new GHC JS backend)

Note the pr #57 contains almost 40 commits, and was a major step forward for io-sim ecosystem. We also prepared a draft pr #4281 which updates ouroboros-network.

Other changes for 1.0.0.0 release on Hackage:

  • Refactored test suite (pr #47)
  • Updated documentation, cabal files, CONTRIBUTING, SECURITY documents, etc in pr #60, currently under review.

· 3 min read
Marcin Szamotulski

Open Source Quarterly Update​

2022-11 - 2023-01​

Summary​

In the last quarter the open-source initiative delivered a comprehensive report on the state of our repositories. As part of this work stream we identified the key open-source repositories for the cardano project across all the projects From a list of more than 500 repositories (some of which are forks) we identified key repositories which constitute the core of Cardano. 20 of them were identified as to be transferred to the future MBO which will govern Cardano development. Some where excluded (like io-sim and typed-protocols), to be govern by IOG, since they have a much broader application than Cardano itself, and thus we think their open-source future will be better outside of the Cardano umbrella.

Christian Taylor identified a number of ways we can improve our repositories to make them more attractive for open-source contributions by analysing each of them. This includes adding or improving various documentation files, like CONTRIBUTING files, adding code of conduct, improving readme files, issue & pull request templates etc. Christian also computed various interesting metrics which gives a very good insight into the development practices: e.g. average merge ratio, average number of reviews, comments and many more! The presentation is available here.

We followed with work on the Cardano Engineering Handbook. We included a standard code of conduct which is now used by most important projects in the Cardano space. We included cardano-node's security policy and added a responsible disclosure policy. We also described how roles and responsibilities should be clarified. This progress was made by a collaborative effort of the Cardano Core, Plutus and Architecture teams, and it wouldn't be possible without Michael Peyton Jones, Arnaud Bailly, Kevin Hammond, Jared Corduan and Marcin Szamotulski.

We also improved the documentation of key repositories, by adding description, improving their README file & CONTRIBUTING files, adding code of conducts following the Cardano Engineering Handbook. This includes improvements to:

And also

The work was carried by Marcin Szamotulski, Addie Girouard and Jared Corduan.

In this quarter we also identified a number of projects which can be published to Hackage (Haskell's package repository) or crate (Rust package repository). The list contains 21 packages, 2 of which (hedgehog-extras and quickcheck-dynamic) are already published on Hackage and another 5 (from the io-sim repository) are close to be published.

Detailed log​

The progress of the open-source project is tracked in this project.

· 4 min read
Damian Nadales

Consensus Quarterly Update​

2022-09 - 2022-11​

Main achievements​

UTxO HD​

  • As a consequence of the errors observed when running distributed mempool benchmarks, we re-designed the UTxO HD mempool integration, which fixed these errors and lead to a simpler and more maintainable design.

  • We focused on increasing test coverage for the UTxO-HD prototype. In particular, we added property tests for:

    • Backing store (work ongoing)
    • Era transitions

  • The property tests we added uncovered several bugs, which is a great result given the exponential increase in the cost of finding bugs as they are closer to deployment.

  • One of the errors found by our tests required us to work on improvements in the Haskell bindings for LMDB. This work is ongoing.

  • We started working on the mempool property tests that will exercise the new code paths that UTxO HD introduced.

  • We developed, benchmarked and tested an implementation of sequences of differences based on "anti-diffs". Performance results of diff sequence operations show that we achieved a speedup of about 4x across several scenarios. Note: this speedup is taking into account diff sequence operations only, so the consensus-wide speedup is less than 4x.

  • We integrated the "anti-diff" prototype into the UTxO HD feature branch.

Genesis​

  • We wrote a simulator that demonstrates soundness of an abstract implementation of the new chain selection rule.
  • We elaborated a draft specification for the Genesis implementation (currently awaiting feedback from other architects).
  • We elaborated a draft specification for the ChainSync Jumping optimization. In particular, this includes a proof sketch that the latter preserves liveness and safety in all cases.
  • With the Networking team, we co-designed the eclipse avoidance mechanism, specifically its coherence with the Genesis implementation plan's security and its dependence on the new ChainSync Jumping optimization.
  • We implemented a prototype for ChainSync Jumping. Initial benchmarks showed a performance degradation wrt the baseline. Our optimization attempts so far have brought the performance closer to the baseline, but not yet to parity.

Conway era​

  • We did most of the heavy lifting required to integrate the Conway era into the Consensus layer.

Technical debt​

  • We started working on enabling CI nightly tests, which revealed several test failures due to thunks being found it data structures used by the ledger and consensus. We made a lot of progress fixing those thunk errors, but some errors still remain.

  • We elaborated a db-analyser benchmark for the ledger operations. This led us to the identification of high processing time at epoch boundaries, and we could not observe any performance degradation that can be attributed to era changes.

  • We fixed a source of flakiness in the ChainDB QSM test.

  • We clarified a common source of confusion around VRF tie-breaking and cross-era chain selection.

  • We fixed a bug in the maximum-allowed ledger major protocol version.

Fostering collaboration​

  • We spent time making cardano-updates the central source of information for the core teams stakeholders.
  • We went through the Galois gap analysis and extracted actionable points to take on next.
  • Bart and Yogesh continued with their onboarding and stated making substantial contributions to consensus.

Next steps​

UTxO HD​

  • Finish the mempool property tests.
  • Benchmark the latest version of the prototype.
  • Elaborate a document that describes new integration test scenarios and pass it to the SDET team.
  • Bring query UTxO by address command performance on par with the baseline version.

Genesis​

  • Receive and incorporate Duncan's feedback on the first draft specification for the Genesis implementation.
  • Begin prototyping the first genesis implementation, unless the first draft needs major changes.
  • Draft a second revision of the Genesis report.
  • Review the second revision with a wider audience, which includes at least Alexander Russell. That feedback will drive a third and hopefully final revision.
  • Investigate how to mitigate the ~30% slowdown we have observed so far in the ChainSync jumping prototype, and try to mitigate it. In particular, we might need to optimize the existing BlockFetch logic.

Tech debt​

  • Enabling nightly CI tests.

Fostering collaboration​

  • Merge the tutorial document Galois wrote; requires CI integration.
  • Come up with our own documentation improvements, many of which were suggested in the Galois gap analysis.
  • Try to hire a new team member.

· 4 min read
Marcin Szamotulski

Network Quarterly Update​

2022-09 - 2022-11​

Summary of most important improvements​

During this quarter the networking team delivered low level specification of peer sharing & eclipse evasion. We held a session with the consensus & the scientists; we got a positive feedback on the design.

Further we focused on implementation of peer sharing. We produced a detail design and an early implementation.

We prepared the P2P Single Relay Release (cardano-node-1.35.5). It includes over 130 patches of network stack improvements over the previous version 1.35.4, which were accomplished over a longer period of time. Among them are both bug fixes and UX improvements for stake pool operators like simplified format of the topology file, or improvements in the logged messages:

We also provide better integration with systemd (socket activation improvements) or improvements in the networking stack:

  • exit policies,
  • peer metrics improvements,
  • DNS TTL improvements (which make it harder to misconfigure the system, an issue discovered by the performance & monitoring team),
  • do not trigger inbound idle timeout for node-to-client connections (pr #3844), an issue reported to us by Matthias Benkort from Cardano Foundation.

Duncan has been making progress with the input endorsers demo. His simulation provides a useful animated visualisation and live quantification of behaviour of the modeled design.

We also improved our e2e diffusion simulation by implementing header-body split, similar to what the real implementation does.

We also made some advances towards our future goals of P2P release for block producer nodes (pr #3800 - in review) & for Daedalus users (pr #3690 - merged).

Detailed log​

  • We expanded diffusion simulation with block-fetch protocol bringing it closer to the production system.

  • We addressed some additional technical depth in diffusion simulation

  • We slightly improved documentation & CI of io-sim and typed-protocols repositories for open-source contributors.

  • We closed a number of issues towards publishing io-sim on Hackage (only two essential issues are left open).

  • We pushed a branch of typed-protocols which captures one of the developer UX problems in the API which we need to solve.

  • We identified and fixed an issue related to systemd sockets.

  • We identified and fixed an issue in consensus initialisation not giving feedback on early errors.

  • We deployed RT View, identified a number of issues which were communicated to the performance & monitoring team.

  • We finished high level & detailed design of peer sharing, very early implementation of peer sharing is done (note that peer sharing cannot be safely deployed without eclipse evasion & genesis).

  • We finished high level design of eclipse evasion, and started working on a detailed design.

  • We were assigned the role of release engineer for 1.35.5 release (the P2P single relay release); we prepared a cardano-node for 1.35.5 release which contains more than 130 patches of just network stack improvements done over last few months.

  • We diagnosed and fixed an tricky bug in the peer state actions (a component which sits between outbound governor and connection manager). That bug was introduced earlier this year and never released. It was caught by the QA testing framework. We expanded our diffusion simulation to cover such case and also mitigated a chance for reintroducing such a bug in future.

  • We identified and quite likely mitigated a misconfiguration in the benchmarking cluster (next benchmarking run will confirm our hypothesis).

  • We simplified the format of p2p topology file, we got positive feedback from SPOs.

  • We raised severities of some of the logging messages, which is an important improvement for SPOs, exchanges and other users of the system.

  • We worked on input endorsers simulation which gives both animated and quantified live feedback on network operation, using a simplified model of a TCP/IP network.

Next quarter​

  • Release the Single Relay P2P Release 1.35.5.

  • Carry on with Peer Sharing (review, testing).

  • Deliver a talk at Conference on Principles of Distributed Systems 2022 in Brussels, Belgium.

  • Present Detailed Design of Eclipse Evasion and start implementation phase.

  • Work on P2P Block Producer release.

  • Carry on with publishing of io-sim on Hackage.

· 2 min read
Jared Corduan

Ledger Quarterly Update​

2022-09 - 2022-11-04​

  • We finished a minimal ledger era capable of master key rotation. This will be re-purposed our upcoming work.
  • We have the humble beginnings of a proper ledger API.
  • We improved the problematic cost model serialization (recall the song and dance about updating the cost model one epoch after the hard fork).
  • We have added benchmarks for problematic areas.
  • Massive repository restructure and cleanup.
    • Unified and consistent variable name schemes (not completely finished, but nearly there).
    • Massive reduction in type constraints, which causes a lot of developer friction, in our code and also downstream.
    • More organized module structures.
    • Improved generators for our property tests.
    • We removed our dependency on cardano-prelude.
  • The formal ledger model has come a long way.
    • We created a fork of Agda that provides some meta-programming support for the ledger rules.
    • We have a large amount of the basic UTxO support in the model.
    • We can generate a good looking PDF from the model.
    • We can produce Haskell from the model.
    • We have a nice finite set theory library that we can use for many of the ledger rules.
    • We have nix support for the model.

Next steps​

  • Individual tracking of deposits. [issue-3113]
  • Versioned CBOR encoders/decoders. [issue-3014]
  • New ledger era transaction body (and the surround work associated with it).
  • Designs for the next ledger era.

· 2 min read
Jordan Millar

Node-Api-Cli Quarterly Update​

2022-09 - 2022-11-04​

  • Various improvements to tests/CI/GHC 9.2.4 preparations/upgrade to cabal-3.8.1.0
  • Major clean up of stale iusses + PRs.
  • Implementation of stale-bot to mitigate against a proliferation of outdated issues and PRs
  • cardano-api refactoring with the aim of exposing more user friendly functions, particularly concerning transaction construction and querying the node.
  • cardano-cli refactoring with the aim of moving reusable functions to cardano-api. We have made strides here and have managed to improve the interface of transaction construction and validation.
  • General documentation updates and improvements
  • Addition of tx-mempool command which allows users to:
    • Query the node about the current mempool's capacity and sizes
    • Request the next transaction from the mempool's current list
    • Query if a particular transaction exists in the mempool
  • Initial refactoring of cardano-testnet

Next quarter

  • cardano-api
    • Working with Konstantinos and his team to make cardano-api better for dapp developers - we have a google doc for this, I can send it to you privately.
  • cardano-testnet
  • Serenity
    • Continued refactoring of cardano-api and cardano-cli, with the particular focus on extracting re-usable components of cardano-cli and moving them to cardano-api. This is harder to define but will manifest in stuff moving from cardano-cli to cardano-api and is tied in to the cardano-api work specified above.
  • General bug fixing and smaller feature requests for the api/cli that are always coming in. Robert is primarily handling this at the moment as he is relatively new.