## 🍕 More dets on running validators

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<img width="547" alt="Screen Shot 2022-09-23 at 8 46 39 PM"  width="70%" src="https://user-images.githubusercontent.com/1130416/192078957-0ed3b60b-7354-4e02-b439-332b92ff0613.png">
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### tl;dr

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- the validator is responsible for creating a new block and sending it out to other nodes on the network.
- to participate as a validators, a user must deposit 32 ETH into the deposit contract and run 3 pieces of software: 
      - an execution client 
      - a consensus client
      - the engine api
- once activated, validators receive new blocsk from peers (the txs delivered in the block are re-executed, and the block signature is checked).
- the validator then sends a vote (attestation) in favor of that block across the network.
- the timing of blocks is not determined by the mining difficult anymore, but it's fixed:
     - slots (12 seconds)
     - epochs (32 slots)
- in every slot, a committee of validators is randomly chosen, whose votes are used to determine the validity of the block being proposed.
- the first block in each epoch is a checkpoint.

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### validator lifecycle

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The sequence of states that a validator can exist in:

1. deposited: At least 32 ETH has been deposited to the deposit contract by the validator.
2. pending: the validator is in the activation queue waiting to be voted into the network by existing validators.
3. active: currently attesting and proposing blocks.
4. slashing: the validator has misbehaved and is being slashed.
5. exiting: the validator has been flagged for exiting the network, either voluntarily or because they have been ejected.

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### the JSON-RPC interface

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* interface that allows us to write programs that use an Ethereum client as a gateway to an Ethereum network and blockchain.
* the RPC interface is offered as an HTTP service on port 8545. For security reasons it is restricted, by default, to only accept connections from localhost.

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### setting a dedicated hardware

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##### execution client

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* [check estimate of the blockchain size](https://bitinfocharts.com/ethereum/).
* minimum specs:
  - CPU with 4+ cores
  - 16 GB+ RAM
  - fast SSD with at least 1TB free space, up to 12TB+ (bottleneck for your hardware is mostly disk space.
  - interent bandwith ~1.2-1.3 GB download and ~0.9-1 GB upload per hour.


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##### consensus client

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* ~200GB for beacon data.

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##### engine api

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* in order to connect a consensus client, the execution client must generate a jwtsecret:


```
openssl rand -hex 32 > jwtsecret
```

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##### other considerations

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* after downloading a client release and its signature, use some PGP to verify them.
* your router and firewall needs to accept connections on listening ports. By default Ethereum clients use a listener (TCP) port and a discovery (UDP) port, both on 30303 by default.
* execution clients offer RPC API endpoints that you can use to submit transactions, interact with or deploy smart contracts on Ethereum.
* the consensus clients all expose a Beacon API that can be used to check the status of the consensus client or download blocks and consensus data.
* a privacy-preserving way to set up a publicly reachable endpoint is to host the node on your own Tor onion service.