etcd vs Infinispan

etcd is an open-source, strongly consistent distributed key-value store for data used by distributed systems and clusters of machines. It arranges values in hierarchical directories and lets clients watch keys or directories for changes. Clients can read and write values with standard HTTP tools such as curl, and keys may have optional time-to-live expiration. The project uses the Raft protocol and handles leader elections during network partitions, including when a leader machine fails. etcd is a core Kubernetes component and its primary datastore. The project provides pre-built binaries, source builds, and container images. Linux on AMD64 and ARM64 is tier 1; Darwin and Windows on either architecture are tier 3, and other platforms are unsupported. TLS and client-certificate authentication are supported for client and peer connections, but neither is enabled by default. The software is self-hosted and licensed under Apache 2.0, with a listed price of free. The integrations listing includes Kubernetes, CoreDNS, and language client libraries, while warning that third-party tools and libraries there are not tested or maintained by the etcd team.

Infinispan is a free, open-source distributed in-memory database that combines caching with full-text and vector search. Its search capabilities include distributed vector indexes, kNN similarity queries, semantic search, retrieval-augmented generation, and semantic caching. Applications can connect through Hot Rod, REST, Redis, or Memcached, with listed client libraries for Java, Go, JavaScript, C++, .NET, and Python. It can run as an embedded library, standalone server, or container image. Deployment options include a Kubernetes Operator and container images on OpenShift, AWS EC2, Azure, and GCP. Listed cache stores include filesystem, JDBC, SQL, RocksDB, and remote Infinispan clusters. Security features include role- and permission-based access control, security realms, and encryption for inter-cluster traffic and remote endpoints. It supports distributed transactions with optimistic or pessimistic locking, configurable isolation levels, and XA recovery. Native integrations listed include Spring AI, LangChain4j, LangChain, and Quarkus LangChain4j. Infinispan is released under the Apache 2.0 license. Its support policy covers only the latest minor release of a major version, with full, limited, and limited-client support distinctions.