2022-07-27 07:38:03 -05:00
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---
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title: Connecting to Consensus Clients
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sort_key: A3
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---
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2022-07-28 11:00:12 -05:00
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Geth is an [execution client][ex-client-link]. Historically, an execution client alone was enough to
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run a full Ethereum node. However, ever since Ethereum swapped from [proof-of-work][pow-link] (PoW) to
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[proof-of-stake][pos-link] (PoS) based consensus, Geth has needed to be coupled to another piece of
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software called a ["consensus client"][con-client-link].
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2022-07-29 03:48:04 -05:00
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There are five consensus clients available, all of which connect to Geth in the same way.
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This page will outline how Geth can be set up with a consensus client to form a complete Ethereum node.
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## Configuring Geth
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Geth can be downloaded and installed according to the instructions on the
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[Installing Geth](/docs/install-and-build/installing-geth) page. In order to connect to a consensus client,
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Geth must expose a port for the inter-client RPC connection.
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The RPC connection must be authenticated using a `jwtsecret` file. This is created and saved
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to `<datadir>/geth/jwtsecret` by default but can also be created and saved to a custom location or it can be
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self-generated and provided to Geth by passing the file path to `--authrpc.jwtsecret`. The `jwtsecret` file
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is required by both Geth and the consensus client.
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The authorization must then be applied to a specific address/port. This is achievd by passing an address to
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`--authrpc.addr` and a port number to `--authrpc.port`. It is also safe to provide either `localhost` or a wildcard
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`*` to `--authrpc.vhosts` so that incoming requests from virtual hosts are accepted by Geth because it only
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applies to the port authenticated using `jwtsecret`.
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A complete command to start Geth so that it can connect to a consensus client looks as follows:
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```shell
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geth --authrpc.addr localhost --authrpc.port 8551 --authrpc.vhosts localhost --authrpc.jwtsecret /tmp/jwtsecret
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```
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## Consensus clients
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There are currently four consensus clients that can be run alongside Geth. These are:
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[Lighthouse](https://lighthouse-book.sigmaprime.io/): written in Rust
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[Nimbus](https://nimbus.team/): written in Nim
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[Prysm](https://docs.prylabs.network/docs/getting-started/): written in Go
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[Teku](https://pegasys.tech/teku): written in Java
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[Lodestar](https://lodestar.chainsafe.io/): written in Typescript
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It is recommended to consider [client diversity][client-div-link] when choosing a consensus client.
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Instructions for installing each client are provided in the documentation linked in the list above.
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The consensus client must be started with the right port configuration to establish an RPC connection
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to the local Geth instance. In the example above, `localhost:8551` was authorized
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for this purpose. The consensus clients all have a command similar to `--http-webprovider` that
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takes the exposed Geth port as an argument.
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The consensus client also needs the path to Geth's `jwt-secret` in order to authenticate the RPC connection between them.
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Each consensus client has a command similar to `--jwt-secret` that takes the file path as an argument. This must
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be consistent with the `--authrpc.jwtsecret` path provided to Geth.
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The consensus clients all expose a [Beacon API][beacon-api-link] that can be used to check the status
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of the Beacon client or download blocks and consensus data by sending requests using tools such as
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[Curl](https://curl.se). More information on this can be found in the documentation for each consensus client.
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## Validators
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2022-07-28 11:00:12 -05:00
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Validators are responsible for securing the Ethereum blockchain. Validators have staked at least 32 ETH into a
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deposit contract and run validator software. Each of the consensus clients have their own validator software that
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is described in detail in their respective documentation. The easiest way to handle staking and validator
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key generation is to use the Ethereum Foundation [Staking Launchpad][launchpad-link]. The Launchpad guides users
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through the process of generating validator keys and connecting the validator to the consensus client.
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## Using Geth
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2022-07-28 11:00:12 -05:00
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Geth is the portal for users to send transactions to Ethereum. The Geth Javascript console is available
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for this purpose, and the majority of the [JSON-RPC API](/docs/rpc/server) will remain available via web3js
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or HTTP requests with commands as json payloads. These options are explained in more detail on the
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[Javascript Console page](/docs/interface/javascript-console). The Javascript console can be started
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using the following command in a separate terminal (assuming Geth's IPC file is saved in `datadir`):
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```shell
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geth attach datadir/geth.ipc
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```
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## Summary
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2022-07-29 03:48:04 -05:00
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Now that Ethereum has implemented proof-of-stake, Geth users are required to install and run a consensus client.
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Otherwise, Geth will not be able to track the head of the chain. There are five consensus clients to choose from.
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This page provided an overview of how to choose a consensus client and configure Geth to connect to it.
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[pow-link]:https://ethereum.org/en/developers/docs/consensus-mechanisms/pow
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[pos-link]:https://ethereum.org/en/developers/docs/consensus-mechanisms/pos
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[con-client-link]:https://ethereum.org/en/glossary/#consensus-client
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[ex-client-link]:https://ethereum.org/en/glossary/#execution-client
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[beacon-api-link]:https://ethereum.github.io/beacon-APIs
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[engine-api-link]: https://github.com/ethereum/execution-apis/blob/main/src/engine/specification.md
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[client-div-link]:https://ethereum.org/en/developers/docs/nodes-and-clients/client-diversity
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[execution-clients-link]: https://ethereum.org/en/developers/docs/nodes-and-clients/client-diversity/#execution-clients
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[launchpad-link]:https://launchpad.ethereum.org/
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[prater-launchpad-link]:https://prater.launchpad.ethereum.org/
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[kiln-launchpad-link]:https://kiln.launchpad.ethereum.org/
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[ropsten-launchpad-link]:https://ropsten.launchpad.ethereum.org/
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[e-org-link]: https://ethereum.org/en/developers/docs/nodes-and-clients/run-a-node/
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[checklist-link]:https://launchpad.ethereum.org/en/merge-readiness
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