Config Management

etcd51.7k★

etcd is the distributed key-value store that Kubernetes trusts with its cluster state. Raft consensus, strong consistency, and a watch API that notifies you when keys change. If Kubernetes depends on it for everything, it's probably reliable enough for you too. If you need a strongly consistent config store or service discovery backend, etcd is proven at scale. Consul from HashiCorp bundles service discovery, health checking, and a KV store in one package — more features, more complexity. ZooKeeper is the legacy option that etcd replaced in many architectures. Commercially, AWS has Parameter Store and Secrets Manager for simpler config management. The watch API is underrated. Subscribe to key changes and react in real-time — great for dynamic configuration, leader election, or distributed locks. The catch: etcd wasn't designed for large data volumes. It's a config store, not a database. Keep values small (default limit is 1.5MB per request). Running etcd outside of Kubernetes means operating a distributed consensus cluster yourself, which requires understanding quorum, backup strategies, and cluster recovery. Most teams use it indirectly through Kubernetes without realizing it.

Consul29.8k★

Consul is HashiCorp's Swiss Army knife for service networking — service discovery, health checking, KV store, and service mesh in one binary. In a microservices world where services come and go, Consul keeps track of what's running where. If you're running distributed services and need them to find each other, Consul does the job. etcd is the alternative for pure KV and config storage (simpler, used by Kubernetes). ZooKeeper is the legacy option. Eureka from Netflix handles service discovery for Java shops. Commercially, cloud service discovery (AWS Cloud Map, GCP Service Directory) are simpler if you're single-cloud. Consul Connect adds mTLS between services without code changes. The multi-datacenter support is genuinely useful for hybrid cloud setups. The catch: HashiCorp moved Consul to the BSL license, which restricts competing hosted services from offering it. For internal use it's fine, but the community trust took a hit. Also, Consul tries to do everything — discovery, KV, mesh, DNS — and teams often end up using just one feature while paying the operational cost of the full platform. If you only need service discovery, something simpler (like DNS-based discovery in Kubernetes) might suffice.