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Configure for The Merge

New user?

This guidance is targeted at users who are running a node and/or validator using pre-Merge configuration. If you're starting from scratch, see our Quickstart.

Select a configuration#

Merge preparation checklist#

Prysm v3.1.2 supports post-Merge configuration.

If you've ever set the USE_PRYSM_VERSION environment variable to use a release candidate, either clear it via UNSET USE_PRYSM_VERSION (Linux/MacOS) or set USE_PRYSM_VERSION= (Windows).

Verify that you're running Prysm v3.1.2 by issuing the following command: prysm.sh beacon-chain --version (Linux) prysm.bat beacon-chain --version (Windows).

The Before and now section below gives you a high-level comparison between pre-Merge and post-Merge configuration. See the Ethereum.org Merge announcement and Merge readiness checklist for more detailed information.

Review the post-Merge system requirements section below. Note that a 2TB+ SSD is highly recommended.

Use geth version to check Geth's version. See Geth's releases page and join their Discord to stay up to date as we approach Mainnet Merge.

Geth 1.10.22 contains a regression. Update to v1.10.23+ if you haven't already.

If you're not using IPC to connect your beacon node and execution node, ensure that both your execution node and beacon node are configured to use JWT authentication. These instructions are included below, and are also available here: Configure JWT

If you're not using IPC to connect your beacon node and execution node, your beacon node will need to connect to its execution node on port 8551. Previously, port 8545 was used. If your beacon node and execution node are on different host machines, ensure that your firewall rules are updated accordingly, and refer to Configure ports and firewalls for improved network connectivity for general connectivity improvement tips.

If you're running a validator, configuring a fee recipient address will allow you to earn what were previously miners' transaction fee tips. Instructions are provided below, and also here: Configure a Fee Recipient address.

See Check node and validator status to learn how to check the status of your execution node, beacon node, and validator node.

The Merge: Before and now#

BeforeNow
You don't need to run a local execution client. You can use a service like Infura instead.You do need to run an execution client. You can't use Infura as an execution endpoint provider.
The HTTP connection between beacon node and execution node doesn't need to be authenticated using a JWT token.The HTTP connection between beacon node and execution node does need to be authenticated using a JWT token.
Beacon nodes connect to execution nodes on port 8545 by default when using HTTP.Beacon nodes connect to execution nodes on port 8551 by default when using HTTP.
Miners receive transaction fee tips.Validators receive transaction fee tips. The "fee" is now a base fee that's burned - block producers earn only transaction fee tips.
A fee recipient address does not need to be specified.A fee recipient address does need to be specified.
A 1TB hard drive is enough.A 2TB+ SSD is highly recommended.

Post-Merge system requirements#

Node typeBenefitsRequirements
Execution + beacon
  • Contributes to the security of Ethereum's ecosystem.
  • Lets you access the Ethereum network directly without having to trust a third party service.
  • Lets you run a validator post-Merge.
  • Software: Execution client, beacon node client (instructions for clients below), curl
  • OS: 64-bit Linux, Mac OS X 10.14+, Windows 10+ 64-bit
  • CPU: 4+ cores @ 2.8+ GHz
  • Memory: 16GB+ RAM
  • Storage: SSD with at least 2TB free space
  • Network: 8 MBit/sec broadband
ValidatorLets you stake ETH, propose + validate blocks, earn staking rewards + transaction fee tips.
  • Everything above, plus...
  • Software: Validator client, browser-based crypto wallet (instructions below)
  • Hardware: (Recommended) A new machine that has never been connected to the internet that you can use to securely generate your mnemonic phrase and keypair
  • 32 ETH (Mainnet)
  • 32 testnet ETH (Testnets)

Best practices#

Configure JWT authentication

The HTTP connection between your beacon node and execution node needs to be authenticated using a JWT token. There are several ways to generate this JWT token:

  • Use an online generator like this. Copy and paste this value into a jwt.hex file.
  • Use a utility like OpenSSL to create the token via command: openssl rand -hex 32 | tr -d "\n" > "jwt.hex".
  • Use an execution client to generate the jwt.hex file.
  • Use Prysm to generate the jwt.hex file:
## Optional. This command is necessary only if you've previously configured USE_PRYSM_VERSIONUSE_PRYSM_VERSION=v3.1.2
## Required../prysm.sh beacon-chain generate-auth-secret

Prysm will output a jwt.hex file path.

Ensure that the script, user, or terminal window used to create and access your JWT token has the permissions it needs. Windows users may need to run command windows as Administrator.

Configure execution node#

Your execution node needs to expose a new port and then use the JWT token to authenticate your beacon node's connection to that port.

Using the latest version of your execution client software, issue the following command to configure your execution node's JWT token and Engine API endpoint:

Download and run the latest 64-bit stable release of the Geth installer for your operating system from the Geth downloads page.

Note that Geth 1.10.22 contains a regression. Update to v1.10.23+ if you haven't already.

Navigate to your execution directory and run the following command to start your execution node:

geth --http --http.api eth,net,engine,admin --authrpc.jwtsecret /path/to/jwt.hex

See Geth's command-line options for parameter definitions.

Syncing can take a long time - from hours to days. You can proceed to the next step while your execution node syncs.

Configure beacon node#

Next, we'll configure your beacon node to consume your JWT token so it can form an authenticated HTTP connection with your execution node.

In this step, you'll run a beacon node using Prysm.

Use the following command to start a beacon node that connects to your local execution node:

./prysm.sh beacon-chain --execution-endpoint=http://localhost:8551 --jwt-secret=path/to/jwt.hex --suggested-fee-recipient=0x01234567722E6b0000012BFEBf6177F1D2e9758D9

If you're running a validator, specifying a suggested-fee-recipient wallet address will allow you to earn what were previously miner transaction fee tips. See How to configure Fee Recipient for more information about this feature.

Your beacon node will now begin syncing. This usually takes a couple days, but it can take longer depending on your network and hardware specs.

Congratulations - you’re now running a full, Merge-ready Ethereum node. To check the status of your node, visit Check node and validator status.

Configure validator node#

Verify that your beacon node and execution node are both fully synced. If you're not fully synced, you risk being penalized and losing some of your staked ETH.

Other than ensuring that you're using the latest stable Prysm release, validator client configuration doesn't need to be updated for The Merge. A fee recipient address can optionally be configured on your validator node if you want redundancy or multiple fee recipient addresses. See Configure a Fee Recipient address to learn more.

Ensure that you're not running multiple instances of the same validator public key, especially if you're using scripts or other forms of automation. If the Ethereum network detects two instances of the same validator key submitting proposals, attestations, or votes, it may assume malicious intent and slash accordingly.

Congratulations!

You’re now running a post-Merge configuration. If you have any questions, feel free ask them on our Discord.

Frequently asked questions#

I'm currently running a validator on Ethereum Mainnet. When should I make changes?
You should make these changes now, regardless of the network you're running on.

Can I use IPC post-Merge?
Yes. You also won't have to worry about JWT if you use IPC. See our Quickstart for IPC instructions.

Can I use a light node with Prysm, or do I need to run a full execution node?
No - at this time, a full node is required.