Module: ETCD

ETCD is a distributed, reliable key-value store for critical system configuration data.

Pigsty uses etcd as a DCS (Distributed Config Store). It is critical for PostgreSQL high availability and automatic failover.

The ETCD module depends on NODE. The PGSQL module requires ETCD. Install NODE to manage nodes before you install ETCD.

Deploy the ETCD cluster before any PGSQL cluster. For PostgreSQL high availability, patroni and vip-manager depend on etcd. They use it for HA and to bind the L2 VIP to the primary.

flowchart LR
    subgraph PGSQL [PGSQL]
        patroni[Patroni]
        vip[VIP Manager]
    end

    subgraph ETCD [ETCD]
        etcd[DCS Service]
    end

    subgraph NODE [NODE]
        node[Software Repo]
    end

    PGSQL -->|depends| ETCD -->|depends| NODE

    style PGSQL fill:#3E668F,stroke:#2d4a66,color:#fff
    style ETCD fill:#5B9CD5,stroke:#4178a8,color:#fff
    style NODE fill:#FCDB72,stroke:#d4b85e,color:#333

    style patroni fill:#2d4a66,stroke:#1e3347,color:#fff
    style vip fill:#2d4a66,stroke:#1e3347,color:#fff
    style etcd fill:#4178a8,stroke:#2d5a7a,color:#fff
    style node fill:#d4b85e,stroke:#b89a4a,color:#333

One etcd cluster serves multiple PostgreSQL clusters in each Pigsty deployment.

Pigsty enables RBAC by default. Each PostgreSQL cluster uses separate credentials to isolate tenants. Administrators use the etcd root user, which has full permissions over all PostgreSQL clusters.