# amaters-cluster TODO
## Implementation Status
**Phase 1 (Raft Consensus)**: ✅ **COMPLETED** (January 2026)
- Core Raft state machine with Follower, Candidate, and Leader states
- Leader election with randomized timeouts
- Log replication with AppendEntries RPC
- Commit index advancement with quorum-based commits
- Comprehensive unit tests (39+ tests passing)
**Phase 2-6**: 📋 Planned for future implementation
## Implemented Modules
- `error.rs` - Raft-specific error types
- `types.rs` - Core types (NodeId, Term, RaftConfig, NodeState)
- `log.rs` - Log management with in-memory cache
- `state.rs` - Persistent and volatile state management
- `rpc.rs` - RequestVote and AppendEntries RPC messages
- `node.rs` - Main RaftNode implementation
## Phase 1: Raft Consensus ✅
### Core Raft Implementation ✅
- [x] State machine
- [x] Follower state
- [x] Candidate state
- [x] Leader state
- [x] State transitions
- [x] Leader election
- [x] Election timeout randomization
- [x] Vote request handling
- [x] Vote granting logic
- [x] Term management
- [x] Log replication
- [x] AppendEntries RPC
- [x] Log consistency checks
- [x] Commit index advancement
- [x] Apply to state machine
- [x] Safety guarantees
- [x] Election safety (term-based voting)
- [x] Leader append-only (log entries never deleted from leader)
- [x] Log matching (consistency checks via prev_log_index/term)
- [x] State machine safety (commit only after quorum replication)
### Log Management ✅
- [x] Log structure
- [x] Entry format (term, index, command)
- [x] Persistent storage interface
- [x] In-memory cache
- [ ] Log compaction (Future work)
- [ ] Snapshot creation
- [ ] Snapshot storage
- [ ] Snapshot transfer
- [ ] Log truncation
- [ ] Recovery (Future work)
- [ ] Load logs on startup
- [ ] Replay committed entries
- [ ] Handle corrupted logs
### Configuration ✅
- [x] Static configuration
- [x] Peer list
- [x] Node ID
- [x] Timeouts (election timeout range, heartbeat interval)
- [ ] Dynamic membership (Future work)
- [ ] Add server
- [ ] Remove server
- [ ] Joint consensus
- [ ] Configuration log entries
## Phase 2: Encrypted Logs 📋
### Encryption Layer
- [ ] Encrypt log entries
- [ ] Use client public keys
- [ ] Store encrypted commands
- [ ] Preserve operation metadata
- [ ] Integrity verification
- [ ] Hash-based verification
- [ ] Merkle tree for batch verification
- [ ] Detect tampering
- [ ] Key management
- [ ] Rotate encryption keys
- [ ] Handle key expiry
- [ ] Key revocation
### Verifiable Computation
- [ ] ZK-SNARKs integration
- [ ] Proof generation
- [ ] Proof verification
- [ ] Circuit design
- [ ] Proof storage
- [ ] Store proofs with log entries
- [ ] Compact proof representation
- [ ] Verification pipeline
- [ ] Verify before apply
- [ ] Handle invalid proofs
- [ ] Audit trail
## Phase 3: Sharding 📋
### Placement Driver (PD)
- [ ] Shard metadata
- [ ] Track shard locations
- [ ] Monitor shard sizes
- [ ] Track shard health
- [ ] Shard assignment
- [ ] Assign shards to nodes
- [ ] Handle node failures
- [ ] Balance load
- [ ] Metadata storage
- [ ] Persist shard mappings
- [ ] Replicate metadata
- [ ] Fast lookups
### Key Range Partitioning
- [ ] Range calculation
- [ ] Divide keyspace into ranges
- [ ] Handle hash-based distribution
- [ ] Support custom partitioners
- [ ] Range metadata
- [ ] Start/end keys
- [ ] Size estimates
- [ ] Access patterns
- [ ] Range queries
- [ ] Route to correct shards
- [ ] Merge results
- [ ] Handle shard splits
### Shard Operations
- [ ] Shard split
- [ ] Detect hot shards
- [ ] Split at median key
- [ ] Migrate data
- [ ] Update metadata
- [ ] Shard merge
- [ ] Detect cold shards
- [ ] Combine adjacent shards
- [ ] Migrate data
- [ ] Update metadata
- [ ] Shard transfer
- [ ] Copy data to new node
- [ ] Verify transfer
- [ ] Switch traffic
- [ ] Delete old data
### Load Balancing
- [ ] Metrics collection
- [ ] CPU usage per shard
- [ ] Memory usage per shard
- [ ] Request rate per shard
- [ ] Storage size per shard
- [ ] Rebalancing algorithm
- [ ] Detect imbalance
- [ ] Calculate moves
- [ ] Execute moves
- [ ] Verify balance
- [ ] Automatic rebalancing
- [ ] Background monitoring
- [ ] Trigger conditions
- [ ] Rate limiting
- [ ] Rollback support
## Phase 4: Fault Tolerance 📋
### Failure Detection
- [ ] Heartbeat mechanism
- [ ] Send periodic pings
- [ ] Detect missing heartbeats
- [ ] Configurable timeouts
- [ ] Health checks
- [ ] Node health status
- [ ] Shard health status
- [ ] Network health
- [ ] Failure types
- [ ] Node crash
- [ ] Network partition
- [ ] Slow nodes
### Recovery Mechanisms
- [ ] Automatic failover
- [ ] Elect new leader
- [ ] Redirect traffic
- [ ] Update metadata
- [ ] Data recovery
- [ ] Restore from replicas
- [ ] Replay log entries
- [ ] Verify consistency
- [ ] Split-brain prevention
- [ ] Quorum checks
- [ ] Fencing tokens
- [ ] Last-write-wins conflict resolution
## Phase 5: Observability 📋
### Metrics
- [ ] Cluster metrics
- [ ] Node count
- [ ] Leader status
- [ ] Election count
- [ ] Raft metrics
- [ ] Log size
- [ ] Commit index
- [ ] Applied index
- [ ] Term number
- [ ] Shard metrics
- [ ] Shard count
- [ ] Shard sizes
- [ ] Rebalance operations
- [ ] Performance metrics
- [ ] Throughput
- [ ] Latency
- [ ] Queue depths
### Monitoring
- [ ] Dashboard
- [ ] Cluster topology
- [ ] Node status
- [ ] Shard distribution
- [ ] Alerts
- [ ] Node failures
- [ ] Split-brain detection
- [ ] Slow operations
- [ ] Logs
- [ ] Structured logging
- [ ] Log levels
- [ ] Log aggregation
## Phase 6: Testing 📋
### Unit Tests
- [ ] Raft state machine tests
- [ ] Election tests
- [ ] Log replication tests
- [ ] Snapshot tests
- [ ] Sharding logic tests
### Integration Tests
- [ ] Multi-node cluster tests
- [ ] Leader election scenarios
- [ ] Log replication scenarios
- [ ] Membership changes
### Chaos Tests
- [ ] Random node failures
- [ ] Network partitions
- [ ] Clock skew
- [ ] Message delays
- [ ] Message loss
- [ ] Simultaneous failures
### Performance Tests
- [ ] Throughput benchmarks
- [ ] Latency benchmarks
- [ ] Scale tests (100+ nodes)
- [ ] Large log tests (1M+ entries)
## Dependencies
- [ ] `raft` or implement custom
- [ ] `amaters-core` - Core types
- [ ] `amaters-net` - Networking
- [ ] `tokio` - Async runtime
- [ ] `parking_lot` - Synchronization
## Configuration
- [ ] TOML-based configuration
- [ ] Environment variables
- [ ] Dynamic reconfiguration
- [ ] Configuration validation
## Documentation
- [ ] Architecture overview
- [ ] Raft protocol explanation
- [ ] Sharding strategy
- [ ] Failure scenarios
- [ ] Operations guide
- [ ] Troubleshooting guide
## Notes
- Raft requires odd number of nodes (3, 5, 7)
- Encrypted logs make debugging harder - plan accordingly
- ZK-SNARKs add verification overhead
- Test failure scenarios extensively
- Monitor cluster health continuously