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· One min read
Damian Nadales

High level summary

  • Assisted with Node release 9.0:
    • Performed security audits, engaged with other teams, implemented improvements, and released Consensus packages.
  • We are now running additional NoThunks tests, which help us safeguard against memory leaks in the node.
  • Reviewed Milestone 13 of Genesis, which improves the code documentation of Genesis, and implements some fixes and optimizations.

· 2 min read
Jean-Philippe Raynaud

High level overview

This week, the Mithril team worked on supporting Cardano node version 9.0.0 and started working on a new Mithril distribution. They also continued implementing the certification of Cardano transactions in Mithril networks. They fixed some bugs blocking the REST API during transactions import, causing resource exhaustion on the aggregator Cardano node, and creating some exceptions in the explorer. They also kept redacting a draft CIP for the diffusion of Mithril signatures through the Cardano network.

Finally, the team worked on enhancing the artifact production in the aggregator to avoid blocking the certification and finalized enforcing the linting of all the files in the repository with the CI.

Low level overview

  • Completed the issue Upgrade Cardano node 9.0.0 #1787
  • Completed the issue Aggregator/Signer preload transactions when Cardano transactions certification is not activated #1782
  • Completed the issue Explorer does not handle invalid transaction hashes #1784
  • Completed the issue Cardano transactions import blocks aggregator and signer #1797
  • Completed the issue Resource exhausted on Cardano node socket #1803
  • Completed the issue Certificate pending route overwhelms the Cardano node in aggregator #1804
  • Completed the issue Optimize Cardano transaction prover performances with parallelization #1756
  • Completed the issue Lint Markdown/JavaScript files in repository #1754
  • Worked on the issue CIP for Mithril signature diffusion through Cardano network #1775
  • Worked on the issue Release 2428 distribution #1810
  • Worked on the issue Non blocking artifact production in aggregator #1792
  • Worked on the issue Cardano transaction importer does not import the last block advertised as certified #1785

· 2 min read
Marcin Szamotulski

High-level overview of sprint 65

Karl Knutsson (CF) fixed a bug which prevented a node using bootstrap peers to sync using them, for a more detailed description see ouroboros-network#4899.

Earlier this year we fixed bugs in IOSimPOR which prevent us from using it in ouroboros-network (io-sim#153, io-sim#159); since ouroboros-network#4872 was merged we have a large number of tests that are using IOSimPOR's schedule exploration. In the last sprint we fixed some bugs discovered by IOSimPOR in ouroboros-network:

We continued working on new tx-submission logic: ouroboros-network#3311 as well as on Genesis. The work on Genesis is split in a few PRs which are currently in review process:

  • Big Ledger Peer Targets for Genesis - ouroboros-network#4832
  • Feed peer selection governor with big ledger peers obtained from a snapshot - ouroboros-network#4850
  • Introduction of serialization instances in support of ledger peer snapshot - ouroboros-network#4851
  • Verification of big ledger peer snapshot file - [ouroboros-network#4888]

High-level overview of sprint 64

Karl Knutsson (CF) modified peer sharing behaviour to not share peers whith which connections failed, see ouroboros-network#4883 for more details.

We fixed inbound governor counters tracer, see ouroboros-network#4885.

· 3 min read
John Lotoski

High level summary

The SRE team continues work on cardano environment improvements and general environment maintenance.

Some notable recent changes, updates or improvements include:

  • Cardano-node 9.0.0 is now deployed to mainnet, preprod, preview, private and shelley-qa environments. The last several weeks have been very busy with pre-release and release activity and environment upgrades involving cardano-node versions 8.9.3, 8.9.4, 8.12.0-pre, 8.12.1, 8.12.2 and now 9.0.0 as of this update.

  • Sanchonet environment remains pinned at cardano-node version 8.11.0-pre until the next respin which will support 9.0.0 or greater.

  • Ogmios service and package options were added to cardano-parts.

  • Four documents were added to cardano-playground to better explain some operational procedures: debugging of peer-to-peer connections; governance voting with the playground stakepools; faucet setup; faucet pool de-delegation. Found at: docs/explain

  • One document was added to cardano-mainnet to explain cardano-snapshot operations. Found at: docs/explain

  • Private chain was stopped and re-spun with 2 hr epochs for testing.

  • Hydra and performance cluster machines had their configuration updated to be more robust to transient nix store caches outages which may re-occur in the future.

  • All machines in cardano-playground and cardano-mainnet clusters were updated to nixpkgs 24.05.

Lower level summary


  • Sets cardano-node to 8.12.2 as well as usage of a custom gc delay parameter branch for bootstrap nodes. Updates all machines to nixpkgs to 24.05 with openssh 9.8p1. Adds one new explainer readme document, new alerts and various script, recipe, and other improvements. See the PR description for more details: cardano-mainnet-pull-16


  • Bumps to cardano-node 9.0.0, adds coredump metrics, adds OOM/coredump alerting, adjusts systemd stop timeout to avoid some unneccesary chain replays: cardano-ops-compare


  • Sets cardano-node (release) and cardano-node-ng (pre-release) versions to 8.12.2 and cardano-db-sync-ng to sancho-5-0-0. Updates nixpkgs to 24.05. Includes nixosModule, dashboard, metric, alert and recipe improvements and new features. More detail is available in the PR description: cardano-parts-pull-43


  • Adjusts nix config to avoid R2 500 errors on transient cache problems and adds explorer to perf class: cardano-perf-compare


  • Sets cardano-node (release) and cardano-node-ng (pre-release) versions to 8.12.2 and cardano-db-sync-ng to sancho-5-0-0. Updates all machines to nixpkgs to 24.05 with openssh 9.8p1. Respins private chain and KES rotates multiple chains. Adds four new explainer readme documents, new alerts and various script, recipe, and other improvements. See the PR description for more details: cardano-playground-pull-27



  • Updates deployers with recent nixpkgs, nix, refactors to preserve legacy nixops usage, adds starship and fzf: ops-lib-pull-134

  • Bumps openssh to 9.8p1 ops-lib-pull-135

· 2 min read
Alexey Kuleshevich

High level summary

This period we added some last minute changes that were necessary for improving resilience and safety of Conway implementation:

  • Authorization of hot credentials for constitutional committee members is now only possible for cold credentials that are present in the ledger state, either in the current committee or in one of the proposals.
  • Voting is restricted to entities that are present in the ledger state
  • DRep votes will be removed whenever DRep unregisters
  • Pricing model for the size of reference scripts was changed from linear to exponential. Moreover, extra limits on the total size of reference scripts being used have been put in place.

Low level summary


  • pull-4430 - CostModel json parsing
  • pull-4438 - Fix UTXOW era in diagrams for Conway
  • pull-4443 - Make reference scripts fee grow exponentially with size
  • pull-4436 - Authorize known cc members only
  • pull-4433 - Improve resilience of future PParams
  • pull-4453 - Tx refscript size check
  • pull-4452 - Prevent votes for non existent entities
  • pull-4450 - BBODY refscript size check


  • pull-4417 - constrained-generators: use consistent warning pragma
  • pull-4431 - constrained-generators: fix flakyness in set generator
  • pull-4312 - Convert AlonzoValidTxUTXOW to ImpTest (Part 1)
  • pull-4386 - Increase the size of the committee for testing
  • pull-4425 - Conformance test plumbing: EPOCH
  • pull-4442 - Update executable-spec SRP
  • pull-4405 - Add more scripts to alonzo utxosspec
  • pull-4445 - Conformance tests plumbing: NEWEPOCH
  • pull-4460 - Remove unnecessary allocation in non-integral reference code
  • pull-4457 - Conformance: POOL: Translate and adjust

Infrastructure and releasing