Open-source alternatives to Zookeeper

This project is a comprehensive Java backend engineering guide and technical reference focused on high-concurrency design, distributed systems, and microservices architecture. It provides detailed strategies for decomposing monolithic applications, managing service discovery, and implementing the architectural patterns required for scalable backend environments. The repository distinguishes itself through an extensive collection of big data algorithmic references and database scaling strategies. It covers memory-efficient techniques for analyzing massive datasets, such as Top-K element extrac

etcd is a distributed, strongly consistent key-value store designed to provide reliable storage for critical system metadata and coordination primitives. It functions as a distributed consensus engine, utilizing a replicated log and leader-based state machine to ensure that all nodes in a cluster maintain a synchronized view of data. By providing atomic operations and linearizable reads and writes, it serves as a foundational component for distributed systems requiring high availability and fault tolerance. The system distinguishes itself through its multi-version concurrency control, which e

userver is a comprehensive C++ backend application platform and asynchronous framework designed for building scalable microservices. It provides a high-performance execution environment for deploying services that communicate via gRPC and HTTP using a middleware-based request pipeline. The platform distinguishes itself through a distributed service orchestration toolset that manages shared state, distributed locking, and dynamic configuration updates without requiring process restarts. It utilizes a coroutine-based asynchronous execution model and event-loop network I/O to handle high-concurr

BullMQ is a Redis-backed message queue library and background processor designed for distributed task queueing. It functions as a distributed queue manager and task scheduler, utilizing Redis to manage asynchronous job processing and persistence. The system distinguishes itself through its role as a job workflow orchestrator, enabling the definition of complex parent-child job dependencies and hierarchies for multi-step workflows. It provides sandboxed process execution to isolate heavy workloads and prevent event loop blocking, alongside distributed rate limiting to protect downstream servic

Skynet is a distributed game server framework designed for building scalable online game backends. It utilizes distributed actor-based clusters and real-time network communication to manage high-concurrency session coordination across multiple nodes. The framework includes a cluster management orchestrator for coordinating services via cluster-wide messaging and dynamic configuration updates. It features a multi-protocol network gateway supporting TCP, UDP, and WebSockets, alongside a data encoding layer using BSON and Sproto serialization for efficient information transfer between distribute

This project is a Chinese language translation of the original research paper detailing the Raft consensus protocol. It serves as a technical research translation and a consensus protocol guide, making the specifications of the Raft algorithm accessible to Chinese speakers. The documentation covers the core mechanisms of distributed systems, including leader election, log replication, and safety protocols. It provides a detailed explanation of how to maintain a single source of truth across multiple servers to achieve fault-tolerant cluster management. The material addresses distributed stat

Redis is a high-performance in-memory key-value store that functions as a distributed cache, message broker, and NoSQL database. It provides sub-millisecond read and write access to data stored in RAM and can operate as a vector database for indexing high-dimensional embeddings. The system supports a wide range of data storage and synchronization primitives, including the management of strings, hashes, lists, sets, and JSON documents. It enables real-time data operations through atomic transactions, hybrid persistence using snapshots and append-only logs, and high-availability configurations

Hazelcast is a distributed data platform that combines an in-memory data grid with a stream processing engine to support real-time analytics and event-driven applications. It functions as a partitioned, distributed key-value store that replicates data across cluster nodes to provide low-latency access and high availability. The platform also serves as a distributed SQL query engine, allowing users to execute standard SQL statements against both in-memory datasets and external data sources. What distinguishes Hazelcast is its use of a distributed consensus subsystem to maintain strongly consis

ToyDB is a distributed SQL database that provides a system for storing and querying data across multiple nodes. It focuses on maintaining strong consistency and fault tolerance through the implementation of a distributed consensus algorithm. The project distinguishes itself by supporting historical data versioning, enabling time-travel queries to retrieve the state of the database from a specific point in the past. It utilizes multi-version concurrency control to manage ACID transactions and ensure data integrity during concurrent operations. The system covers relational data modeling with t

This is a Raft consensus library and distributed consensus engine implemented in Go. It provides the primitives necessary to build fault-tolerant distributed services by implementing a replicated state machine that ensures a group of servers agree on a shared system state through leader election and log replication. The project distinguishes itself through a pluggable architecture for storage backends and snapshot storage, decoupling the consensus logic from physical persistence. It includes specialized mechanisms for leadership transfer, protocol version management to support rolling upgrade

Pigsty is a comprehensive database infrastructure orchestration platform designed to automate the full lifecycle of high-availability PostgreSQL clusters. It functions as an infrastructure-as-code framework that manages cluster coordination, node provisioning, and service discovery through idempotent playbooks. By integrating distributed consensus mechanisms, the platform ensures automated failover and consistent state enforcement across diverse environments, including bare metal and virtualized infrastructure. The platform distinguishes itself through a robust suite of operational capabiliti

RedisInsight is a graphical user interface and management tool for browsing, analyzing, and administering Redis databases. It provides a visual environment for exploring key-value data structures, managing database instances, and performing data analysis across different operating systems and deployments. The tool distinguishes itself by providing dedicated visual managers for complex operations, including a vector database manager for configuring embeddings and similarity searches, a query workbench for executing raw commands and Lua scripts, and a performance monitoring dashboard for tracki

This project provides educational materials and courseware focused on the theoretical and practical foundations of distributed systems design. It serves as a comprehensive curriculum covering the disciplines of consensus, data consistency, reliability engineering, and scalability. The instructional content focuses on achieving cluster agreement through consensus algorithms and managing system-wide state via coordination frameworks. It includes a dedicated guide to data theory, exploring replication strategies, consistency models, and data convergence. The courseware covers a broad capability

OceanBase is a distributed SQL database designed for high availability and strong consistency across multiple nodes and regions. It functions as a hybrid transactional and analytical processing engine, allowing real-time analytics and transactions to execute on a single data copy. The system also serves as a vector database engine for indexing and querying vector data to power semantic search and recommendation systems. The platform features native compatibility layers for MySQL and Oracle, enabling the migration of legacy workloads without rewriting SQL code. It utilizes a Paxos-based distri

Patroni is a high availability manager and cluster orchestrator for PostgreSQL. It functions as an automatic failover controller and replication manager that ensures continuous database availability by automating leader election and promoting standby nodes during failures. The system maintains a consistent cluster state by acting as a distributed consensus coordinator. It synchronizes configuration and manages leader elections through integration with distributed configuration stores such as etcd, ZooKeeper, or Consul. Its broader capabilities include managing both synchronous and asynchrono

This project serves as a comprehensive technical reference for the architecture and design of data-intensive applications. It provides a structured analysis of the fundamental principles required to build reliable, scalable, and maintainable software systems, covering the core trade-offs inherent in modern data infrastructure. The repository explores the mechanics of distributed data management, including strategies for replication, partitioning, and achieving consensus across multiple nodes. It details the design of storage engines, indexing techniques, and transaction management models, whi

Vespa is a distributed search engine, vector database, and machine learning ranking engine. It serves as an AI search platform designed to handle large-scale document indexing and complex query processing across a cluster of nodes, combining keyword retrieval with high-dimensional embedding storage for semantic similarity search. The platform distinguishes itself by integrating machine learning models directly into the search pipeline to perform real-time inference and ranking. It converts these models into ranking expressions to score and order results based on relevance, while providing a s

Apollo is a microservice configuration management system and dynamic configuration center. It serves as a centralized platform for storing, distributing, and syncing application settings across distributed environments to maintain consistency across various clusters. The system distinguishes itself through a dynamic configuration orchestrator that supports real-time updates to connected applications, eliminating the need for manual service restarts. It features a grayscale configuration deployment tool for rolling out changes to a small subset of service instances and a version control system

This project is a web-based management interface designed for the administration, monitoring, and configuration of Nginx server instances. It functions as a centralized platform for managing reverse proxy settings, traffic routing, and server lifecycles, providing a visual dashboard to replace manual configuration file editing. The platform distinguishes itself through integrated infrastructure automation and observability tools. It supports distributed environments by synchronizing configuration states across multiple nodes and containerized services, while offering artificial intelligence a

RoadRunner is a high-performance application server and process manager designed to serve PHP applications using a persistent worker model. It eliminates bootload overhead and initialization time by keeping application processes alive between requests, acting as a protocol-agnostic proxy that routes traffic to a pool of supervised workers. The server is built with a plugin-based modular architecture, allowing it to be extended with custom Go plugins and compiled into tailored binaries. It distinguishes itself by providing a unified execution model for a wide array of communication protocols,

Ignite is a distributed in-memory data grid and compute platform. It functions as a distributed SQL database and storage engine designed to store and process large datasets in RAM to minimize latency and increase calculation speed. The system is distinguished by a multi-tier storage engine that manages data placement across memory and disk to balance high-speed access with large capacity. It features a distributed compute grid that executes custom logic directly on the nodes where data resides to reduce network traffic. The platform provides a broad set of capabilities including ACID transac

InternetArchitect is an educational collection of documents and source code designed as a high concurrency architecture course. It serves as a distributed systems implementation guide, providing technical patterns and practical examples for designing scalable internet architectures that maintain stability under heavy traffic loads. The project focuses on high-performance database optimization and microservices design patterns. It covers strategies for reducing latency and increasing throughput via database sharding and proxy layers, as well as coordinating global state across distributed clus

Otter is a distributed database synchronization system and change data capture tool designed to replicate data between databases across multiple geographic regions. It functions as a synchronization orchestrator and ETL data pipeline that mirrors records and associated files in real time. The system employs incremental log parsing to capture database changes and utilizes a consistency-based convergence algorithm and loop-avoidance logic to manage bi-directional replication. It processes data through a pipeline of selection, extraction, transformation, and loading to handle joins and format co

Redsync is a distributed lock manager and Go Redis client extension designed to ensure exclusive access to shared resources. It implements mutual exclusion across multiple processes by using a Redis backend to coordinate synchronization and prevent race conditions in distributed environments. The library maintains lock validity through quorum-based consensus, requiring successful writes to a majority of independent Redis nodes. It utilizes Lua-scripted atomic operations for acquisition and release, while employing value-based ownership validation and time-to-live expiration to prevent deadloc

This project provides a version of the Redis 3.0 codebase featuring detailed technical commentary and annotations. It serves as a technical resource for studying the internal design and implementation of an in-memory key-value store and the architecture of a networked NoSQL database. The documentation focuses on the implementation of the Redis Sentinel system, covering the mechanisms used for monitoring instance health, managing automatic failover, and notifying clients of primary node changes. The project covers broader architectural areas including in-memory data storage, high availability

Redis is an in-memory, key-value database designed to provide sub-millisecond latency for read and write operations. It functions as a versatile data platform, serving as a distributed cache, a message broker, a NoSQL document store, and a vector database. The system utilizes an event-driven, single-threaded loop to process requests efficiently, while maintaining data durability through append-only persistence logs and asynchronous snapshotting mechanisms. What distinguishes Redis is its ability to handle complex data structures—including strings, hashes, lists, sets, and sorted sets—alongsid

This project is a comprehensive educational repository providing technical documentation and learning materials across a wide range of computer science and software engineering domains. It serves as a centralized knowledge base for developers, covering core programming concepts, database management, distributed systems, and system design principles. The content spans fundamental Java programming, including collection frameworks and runtime environments, alongside deep dives into web communication protocols and browser internals. It also provides extensive resources on database internals, such