Node operator open application begins for Espresso Sequencer Cappuccino testnet

As the Espresso Sequencer edges closer to a production launch, we are looking to onboard more node operators to support our journey towards building a fully permissionless, credibly neutral interoperability layer for rollups.

The Espresso Sequencer runs on HotShot, a consensus protocol designed specifically to prioritize the high throughput and fast pre-confirmations that users have come to expect from rollups. The Espresso Sequencer also targets Ethereum-level security by scaling to thousands of nodes, while also enabling Ethereum validators to participate in securing the Espresso Sequencer network through Ethereum restaking.

Further decentralizing the Espresso Sequencer

Our current and fourth testnet, Gibraltar, is the first shared sequencer network run with external node operators. We have partnered with Blockdaemon, an industry leading public infrastructure company, to run four Espresso Sequencer nodes across North America, Asia, and Europe. This testnet release also sees the Espresso Sequencer support four rollup stacks (Arbitrum, Cartesi, Optimism and Polygon zkEVM) and several collaborations with rollup projects (see our ecosystem map). You can learn more about the Gibraltar release here.

In our upcoming fifth testnet, Cappuccino, we are looking to further decentralize the sequencer by onboarding more entities to run Espresso Sequencer nodes. We are excited to invite node operators to apply to run sequencer nodes on Cappuccino, which is scheduled for release in late Q1 2024.

Cappuccino will enable us to continue developing a seamless node onboarding process. As part of these efforts, we will provide basic metrics such as peer count, synchronization speed, stats on finalized blocks (time, number of transactions, size, etc.) as well as more advanced metrics that will be required for node operators participating in the Espresso Sequencer’s operation.

Cappuccino will implement other roadmap milestones such as fee payments, key management tooling, and verifiable information dispersal, which uses erasure coding to allow nodes to vote on a block without needing to download the whole block.

If you are interested in running an Espresso Sequencer for the Cappucinno testnet, please consider applying here.

Node operator expectations and specifications

We expect Cappuccino to run with approximately 100 nodes that are geographically dispersed, spanning several cloud and bare metal environments. We are looking to partner with organizations who will run nodes during our testnet, provide user feedback, and help us refine node specifications and onboarding for future releases.

Node operators will be expected to set up and run the testnet and provide occasional DevOps support during the Cappuccino testnet deployment. To support the onboarding process, selected node operators will be provided with technical documentation, an onboarding guide, and a metrics API. Espresso Systems will support node operators by providing documentation, a shared Slack channel, and incident response via on-call procedures.

Node technical specifications

The Espresso Sequencer supports a basic module for nodes participating in consensus and data availability (DA). There are additional, optional modules to run an HTTP server that comes with healthcheck and version endpoints, a query service for history, filesystem and SQL storage, submitting a transaction for sequencing, and checking status.

It is also possible to run a DA node. DA nodes will need to store a certain number of blocks at a time on-demand until an archival node can obtain the DA data, with rough guidelines on storage in the below specifications. Non-DA nodes have no need to persist block data and therefore have negligible storage requirements.

Hardware requirements are still in flux as we refine our testnets and add new features, but for now we recommend the following:

• RAM: 16–32 GB.
• CPU: 2–4 cores.
• Storage (DA node): 20 GB minimum, ability to scale to 3 TB on demand.
• Storage (non-DA node): Negligible, 10s-100s of bytes.

The detailed expected technical specifications for the Cappuccino testnet are available here.

Timeline

We are opening up the application process for node operators for two weeks, from February 2 until February 16, 2024. We’ll aim to announce selected node operators by the middle of March 2024.

To show prospective node partners what it’s like running an Espresso Sequencer node, we’ll be hosting an AMA with the Blockdaemon team in our Discord on February 6, 2024 at 11 AM EST. We’ll outline the experience of onboarding as a node operator partner, the support model Espresso Systems provides, and what you can expect if you are selected to run an Espresso Sequencer node. If you’re interested in running an Espresso Sequencer node, please consider attending.

We’re looking forward to hearing from those interested in running an Espresso Sequencer node! Please note that although we will not be able to respond to all applicants individually, we will share progress updates and selection decisions in our Discord via the #node-operators-updates channel.

The node operator questionnaire for the Cappuccino testnet is available here.