# Ethereum Merge Guide - Lighthouse/Geth ## Introduction This guide is intended for anyone currently running mainnet for validators using Lighthouse/Geth. These updates are current as of Sep 4, 2022, installing Lighthouse-V3.1.0 and Geth -V.1.10.25. After completing these updates, your validator will be ready for the Bellatrix hard fork \~Sep 6 and the mainnet merge \~Sep 15!
{% hint style="info" %} This guide is for informational purposes only. Always practice on [testnet](https://someresat.medium.com/guide-to-staking-on-ethereum-ubuntu-g%C3%B6erli-lighthouse-8d0a2a811e6e) first. Feel free to reach out to the [EthStaker Discord](https://discord.io/ethstaker) if you have any questions. {% endhint %} ## Summary 1. Update Geth installation, username, and directory 2. Create JWT Token 3. Geth 1. Update Geth 2. Add `--authrpc.jwtsecret` to geth.service file 4. Lighthouse 1. Update Lighthouse 2. Add `--execution-jwt` and `--execution-endpoint` to lighthousebeacon.service file 3. Add `--suggested-fee-recipient` to lighthousevalidator.service ## New Guides and Improvements There have been a few changes to [Somer Esat's Guides](https://github.com/SomerEsat/ethereum-staking-guides) over time, and we need to make a few updates to keep in line with best practice. The changes include: 1\) Username changed from Goeth to Geth 2\) Rename Geth directory from `/var/lib/goethereum` to `/var/lib/geth` 3\) Remove Personal Package Archive (PPA) installation and switch to using curl {% hint style="info" %} While PPA is convenient, You may not want Geth to update every time you run `sudo apt update`, especially if the latest version has a bug. By using`curl` , you can choose which version to install and run. {% endhint %} ### Geth Changes {% hint style="info" %} These changes won't affect the chain data, and geth will not need to re-sync. {% endhint %} 1\) **Stop Geth:** ``` sudo systemctl stop geth ``` 2\) **Remove Geth:** ``` sudo apt remove -y geth ``` 3\) **Remove Geth PPA:** ``` sudo add-apt-repository --remove ppa:ethereum/ethereum ``` 4\) **Check latest version of Geth:** {% hint style="info" %} Find the most current update [here](https://github.com/ethereum/go-ethereum/releases). This code in this guide is updated for v1.10.25 and current as of Sep 5, 2022. {% endhint %} 5\) **Change to Home directory:** ``` cd ~ ``` 6\) **Use curl to download latest version (be sure to update version):** ``` curl -LO https://gethstore.blob.core.windows.net/builds/geth-linux-amd64-1.10.25-69568c55.tar.gz ``` **7) Extract, Copy, and Clean up (update version):** ``` tar xvf geth-linux-amd64-1.10.25-69568c55.tar.gz cd geth-linux-amd64-1.10.25-69568c55 sudo cp geth /usr/local/bin cd ~ rm geth-linux-amd64-1.10.25-69568c55.tar.gz rm -r geth-linux-amd64-1.10.25-69568c55 ``` 8\) **Rename geth username and group (`goeth` -> `geth`):** ``` sudo usermod -l geth goeth sudo groupmod -n geth goeth ``` 9\) **Rename geth directory to `/var/lib/geth`** ``` sudo mv /var/lib/goethereum /var/lib/geth ``` 10\) **Set permissions for data directory:** ``` sudo chown -R geth:geth /var/lib/geth ``` 11\) **Update other programs:** ``` sudo apt -y update && sudo apt -y upgrade ``` ### Modify geth.service file {% hint style="info" %} ### Note on Code Readability This blob is simply informational, no need to copy any code from here. This guide uses line breaks "`\`" to list each flag on it's own line and make the code easier to understand. The two code examples below are identical, just with different layouts. **Single line layout:** ``` ExecStart=/usr/local/bin/geth --mainnet --datadir /var/lib/geth --authrpc.jwtsecret /var/lib/jwtsecret/jwt.hex ``` **Same code with line breaks:** ``` ExecStart=/usr/local/bin/geth \ --mainnet \ --datadir /var/lib/geth \ --authrpc.jwtsecret /var/lib/jwtsecret/jwt.hex ``` As you can see, the line breaks make the code more readable and clearly identifies each flag. This guide will use line breaks to make the service files more readable. {% endhint %} 1\) **Open geth.service for editing:** ``` sudo nano /etc/systemd/system/geth.service ``` 2\) **Modify geth.service:** {% hint style="info" %} It's easiest to delete everything already in the file, then copy/paste the updated code You can't highlight/delete in the terminal, so just tap `delete` or `backspace`. {% endhint %} 3\) **Copy/Paste the following text into the empty geth.service file:** {% code overflow="wrap" %} ``` [Unit] Description=Geth Execution Client (Mainnet) After=network.target Wants=network.target [Service] User=geth Group=geth Type=simple Restart=always RestartSec=5 ExecStart=/usr/local/bin/geth \ --mainnet \ --datadir /var/lib/geth \ --authrpc.jwtsecret /var/lib/jwtsecret/jwt.hex [Install] WantedBy=default.target ``` {% endcode %} ### Geth service file should look like this: {% hint style="info" %} Once finished, use `` to Exit, `` to save, and `` to confirm {% endhint %}

Your geth.service file should match this image

4\) **Reload Daemon:** ``` sudo systemctl daemon-reload ``` 5\) **Start Geth:** ``` sudo systemctl start geth ``` 6\) **Check Geth logs:** {% hint style="info" %} Geth logs will show an error until you create the JWT token in the next step. {% endhint %} ``` sudo journalctl -fu geth.service ``` ## Create JWT Token The JWT token is used by Execution Engine (Geth) and Consensus Client (Lighthouse) to securely communicate back and forth. These steps will generated a random 32 byte hex that will be referenced by both clients. 1\) **Create directory to store the JWT file:** ``` sudo mkdir -p /var/lib/jwtsecret ``` 2\) **Generate the JWT hex file using `openssl`:** ``` openssl rand -hex 32 | sudo tee /var/lib/jwtsecret/jwt.hex > /dev/null ``` 3\) **Use `ls` (list) to confirm the hex file exists at /`var/lib/jwtsecret`:** ``` ls /var/lib/jwtsecret ``` {% hint style="success" %} If the terminal responds with "`jwt.hex`" as shown below, then the JWT token was successfully created and stored at `/var/lib/jwtsecret` {% endhint %}
## Update Lighthouse Check the most current Lighthouse release [here](https://github.com/sigp/lighthouse/releases). {% hint style="info" %} This guide demonstrates updating to v3.1.0. If a newer version is available, you will need to update the code to the current version on the release page {% endhint %} 1\) **Change directory to the Home folder:** ``` cd ~ ``` 2\) **Remove any old lighthouse file that may exist:** {% hint style="info" %} **Note:** You might get an error if the files don't exist. No worries, just continue. {% endhint %} ``` rm lighthouse rm -r lighthouse ``` **Download Lighthouse software (update version):** ``` curl -LO https://github.com/sigp/lighthouse/releases/download/v3.1.0/lighthouse-v3.1.0-x86_64-unknown-linux-gnu.tar.gz ``` 3\) **Stop Lighthouse services**: ``` sudo systemctl stop lighthousevalidator && sudo systemctl stop lighthousebeacon ``` 4\) **Extract binary from archive (update version)**: ``` tar xvf lighthouse-v3.1.0-x86_64-unknown-linux-gnu.tar.gz ``` 5\) **Copy binary into /usr/local/bin:** ``` sudo cp lighthouse /usr/local/bin ``` 6\) **Start Lighthouse services:** ``` sudo systemctl start lighthousebeacon && sudo systemctl start lighthousevalidator ``` 7\) **Remove old files (update version):** ``` rm lighthouse-v3.1.0-x86_64-unknown-linux-gnu.tar.gz rm lighthouse ``` {% hint style="success" %} Congratulations, Lighthouse is now running on the most current version! {% endhint %} ## Update Beacon config file 1\) **Stop Beacon:** ``` sudo systemctl stop lighthousebeacon ``` 2\) **Open the beacon service file for editing:** ``` sudo nano /etc/systemd/system/lighthousebeacon.service ``` **Copy/paste the following into the terminal:** {% hint style="info" %} Delete everything in the file and copy the text below {% endhint %} ``` [Unit] Description=Lighthouse Consensus Client BN (Mainnet) Wants=network-online.target After=network-online.target [Service] User=lighthousebeacon Group=lighthousebeacon Type=simple Restart=always RestartSec=5 ExecStart=/usr/local/bin/lighthouse bn \ --network mainnet \ --datadir /var/lib/lighthouse \ --http \ --execution-endpoint http://127.0.0.1:8551 \ --execution-jwt /var/lib/jwtsecret/jwt.hex [Install] WantedBy=multi-user.target ``` ### Beacon file should look like this: {% hint style="info" %} Once finished, use `` to Exit, `` to save, and `` to confirm {% endhint %}

Your beacon file should match this image

**2) Reload the daemon:** ``` sudo systemctl daemon-reload ``` 3\) **Restart Beacon:** ``` sudo systemctl restart lighthousebeacon ``` ## Update Validator config file {% hint style="warning" %} After the merge, your validator will receive tips from any blocks you propose. It is important that you send tips to a valid Ethereum address you can access. Be sure to update the `--suggested-fee-recipient` flag as shown below {% endhint %} 1\) **Open the lighthousevalidator.service file for editing:** ``` sudo nano /etc/systemd/system/lighthousevalidator.service ``` **2) Copy/Paste the information below into the terminal** {% hint style="info" %} Delete everything in the file and copy the text below**.** **Don't forget to update the `--suggested-fee-recipient`** {% endhint %} ``` [Unit] Description=Lighthouse Consensus Client VC (Mainnet) Wants=network-online.target After=network-online.target [Service] User=lighthousevalidator Group=lighthousevalidator Type=simple Restart=always RestartSec=5 ExecStart=/usr/local/bin/lighthouse vc \ --network mainnet \ --datadir /var/lib/lighthouse \ --suggested-fee-recipient YourFeeRecipientAddress [Install] WantedBy=multi-user.target ``` {% hint style="info" %} Once finished, use `` to Exit, `` to save, and `` to confirm {% endhint %} ### Merge-ready lighthousebeacon.service file: {% hint style="info" %} The following screenshot shows the fee address set as `0x8fCF8DB7Afaa8C865B693bEeD5858712ABBE4DDb` {% endhint %}

Your validator file should match this image (with different fee address)

3\) **Reload daemon:** ``` sudo systemctl daemon-reload ``` 4\) **Restart Lighthouse Validator:** ``` sudo systemctl restart lighthousevalidator ``` ## Check Logs & Status {% hint style="info" %} You can open multiple terminal windows if you'd like to view all 3 logs at once. Sometimes it helps to maximize the terminal window so you can read the logs more clearly. All services should be running without errors and appear "ready for merge" {% endhint %} 1\) **Check Geth output:** ``` sudo journalctl -fu geth.service ``` 2\) **Check Beacon output:** ``` sudo journalctl -fu lighthousebeacon.service ``` 3\) **Check Validator output:** ``` sudo journalctl -fu lighthousevalidator.service ``` ## Ready For Merge {% hint style="success" %} Congrats! You're all set for the Bellatrix hard fork on Sep 6, and the merge \~Sep 15! {% endhint %}
--- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://agstakingco.gitbook.io/ethereum-merge-guide-lighthouse-geth/ethereum-merge-guide-lighthouse-geth.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.