68 lines
2.2 KiB
Markdown
68 lines
2.2 KiB
Markdown
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# Lighthouse Validator Client
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The Validator Client (VC) is a stand-alone binary which connects to a Beacon
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Node (BN) and fulfils the roles of a validator.
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## Roles
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The VC is responsible for the following tasks:
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- Requesting validator duties (a.k.a. shuffling) from the BN.
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- Prompting the BN to produce a new block, when a validators block production
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duties require.
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- Completing all the fields on a new block (e.g., RANDAO reveal, signature) and
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publishing the block to a BN.
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- Prompting the BN to produce a new shard atteststation as per a validators
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duties.
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- Ensuring that no slashable messages are signed by a validator private key.
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- Keeping track of the system clock and how it relates to slots/epochs.
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The VC is capable of managing multiple validators in the same process tree.
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## Implementation
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_This section describes the present implementation of this VC binary._
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### Services
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Each validator is represented by two services, one which tracks the validator
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duties and another which performs block production duties.
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A separate thread is maintained for each service, for each validator. As such,
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a single validator utilises three (3) threads (one for the base VC and two for
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each service) and two validators utilise five (5) threads.
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#### `DutiesManagerService`
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Polls a BN and requests validator responsibilities, as well as a validator
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index. The outcome of a successful poll is a `EpochDuties` struct:
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```rust
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EpochDuties {
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validator_index: u64,
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block_prodcution_slot: u64,
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}
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```
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This is stored in the `EpochDutiesMap`, a `HashMap` mapping `epoch ->
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EpochDuties`.
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#### `BlockProducerService`
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Polls the system clock and determines if a block needs to be produced. Reads
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from the `EpochDutiesMap` maintained by the `DutiesManagerService`.
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If block production is required, performs all the necessary duties to request,
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complete and return a block from the BN.
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### Configuration
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Presently the validator specifics (pubkey, etc.) are randomly generated and the
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chain specification (slot length, BLS domain, etc.) are fixed to foundation
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parameters. This is temporary and will be upgrade so these parameters can be
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read from file (or initialized on first-boot).
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## BN Communication
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The VC communicates with the BN via a gRPC/protobuf connection.
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