initial

README.md

@@ -1,2 +1,85 @@
-# postgres15replicate
+# postgres15
+
+Implement automatic primary and standby
+
+## Primary
+
+Example `compose.yaml` for **primary** instance.
+
+```yaqml
+services:
+  db:
+    image: pendragon.zone/docker/postgres15replicate
+    restart: unless-stopped
+    shm_size: 128mb
+    environment:
+      POSTGRES_PASSWORD: ${DB_ROOT_PASSWORD}
+      REPLICATOR_PASSWORD: ${REPLICATOR_PASSWORD}
+      MAX_CONNECTIONS: "400"
+
+    network_mode: bridge
+    ports:
+      - 5432:5432
+
+    volumes:
+      - data:/var/lib/postgresql/data
+      - /docker/postgres_wal:/wal_archive
+
+volumes:
+  data:
+```
+
+- Volume `/wal_archive` **must** be mapped to a location available by **all** replication participants.
+
+- `DB_ROOT_PASSWORD` _required_, must be the same for all replication participants.
+
+- `REPLICATOR_PASSWORD` _required_, must be the same for all replication participants.
+
+- `UPSTREAM` **must not** be set for **primary** instance.
+
+- `WAL_ARCHIVE` _default: `/wal_archive`_ use different location for write-ahead-logs.
+
+- `TRIGGER_FILE` _default: `i_am_primary`_, name of the file that promotes a standby instance to primary instance, if it exists in directory `/var/lib/postgresql/data`.
+
+- `WAL_KEEP_SIZE` _default: `1GB`_
+
+- `REPLICATOR_NAME` _default: `replicator`_ name of user for replication.
+
+- `MAX_CONNECTIONS` _optional_, change default value of `max_connections` configuration value.
+
+
+## Standby
+
+Example `compose.yaml` for **standby** instance.
+
+```yaqml
+services:
+  db:
+    image: pendragon.zone/docker/postgres15replicate
+    restart: unless-stopped
+    shm_size: 128mb
+    environment:
+      POSTGRES_PASSWORD: ${DB_ROOT_PASSWORD}
+      REPLICATOR_PASSWORD: ${REPLICATOR_PASSWORD}
+      UPSTREAM: ${UPSTREAM}
+
+    network_mode: bridge
+    ports:
+      - 5432:5432
+
+    volumes:
+      - data:/var/lib/postgresql/data
+      - /docker/postgres_wal:/wal_archive
+
+volumes:
+  data:
+```
+
+- Volume `/wal_archive` **must** be mapped to a location available by **all** replication participants.
+
+- `DB_ROOT_PASSWORD` _required_, must be the same for all replication participants.
+
+- `REPLICATOR_PASSWORD` _required_, must be the same for all replication participants.
+
+- `UPSTREAM` _required_, name of the node to replicate from. Can either be **primary** or a different **standby** instance.