Add pgpool2 configuration

Author: parisk

compose.yml

@@ -1,31 +1,37 @@
 x-base:
   &base
-    secrets:
-      - postgres-password
-      - replicator-password
-    environment:
-      POSTGRES_PASSWORD_FILE: /run/secrets/postgres-password
-      POSTGRES_CIDR: ${POSTGRES_CIDR:-172.54.32.0/24}
-    command: ["postgres", "-c", "log_statement=all"]
+  secrets:
+    - postgres-password
+    - replicator-password
+  environment:
+    POSTGRES_PASSWORD_FILE: /run/secrets/postgres-password
+    POSTGRES_CIDR: ${POSTGRES_CIDR:-172.54.32.0/24}
+  command: ["postgres", "-c", "log_statement=all"]
 
 services:
   primary:
     <<: *base
     build:
-      context: .
+      context: postgres
       target: primary
     volumes:
       - primary_data:/var/lib/postgresql/data
 
   secondary:
     <<: *base
     build:
-      context: .
+      context: postgres
       target: secondary
     restart: on-failure:3
     volumes:
       - secondary_data:/var/lib/postgresql/data
 
+  pgpool2:
+    build:
+      context: pgpool2
+    secrets:
+      - postgres-password
+
 secrets:
   postgres-password:
    file: dev/secrets/postgres-password

pgpool2/Dockerfile

@@ -0,0 +1,19 @@
+FROM ubuntu:22.04 as pgpool
+
+# https://www.pgpool.net/mediawiki/index.php/Apt_Repository
+
+ENV DEBIAN_FRONTEND noninteractive
+
+RUN apt-get update
+RUN apt-get install -y wget gnupg
+RUN echo "deb http://apt.postgresql.org/pub/repos/apt jammy-pgdg main" > /etc/apt/sources.list.d/pgdg.list
+RUN wget --quiet -O - https://www.postgresql.org/media/keys/ACCC4CF8.asc | apt-key add -
+RUN apt-get update
+RUN apt-get install -y pgpool2 libpgpool2 postgresql-16-pgpool2
+RUN apt-get install -y gettext-base 
+
+COPY pgpool2/ /etc/pgpool2/
+COPY bin/docker-entrypoint.sh /usr/local/bin/docker-entrypoint.sh
+
+ENTRYPOINT [ "docker-entrypoint.sh" ]
+CMD [ "pgpool", "-n" ]

pgpool2/bin/docker-entrypoint.sh

@@ -0,0 +1,14 @@
+#! /bin/bash
+
+set -ex
+
+export POSTGRES_PASSWORD=$(cat /run/secrets/postgres-password)
+cat /etc/pgpool2/pgpool.conf.tpl | envsubst > /etc/pgpool2/pgpool.conf
+cat /etc/pgpool2/pool_passwd.tpl | envsubst > /etc/pgpool2/pool_passwd
+unset POSTGRES_PASSWORD
+
+export POSTGRES_PASSWORD_MD5=$(md5sum /run/secrets/postgres-password | awk '{print $1}')
+cat /etc/pgpool2/pcp.conf.tpl | envsubst > /etc/pgpool2/pcp.conf
+unset POSTGRES_PASSWORD_MD5
+
+exec "$@"

pgpool2/pgpool2/pcp.conf.tpl

@@ -0,0 +1,4 @@
+# PCP Client Authentication Configuration File
+# ============================================
+
+postgres:${POSTGRES_PASSWORD_MD5}

pgpool2/pgpool2/pgpool.conf.tpl

@@ -0,0 +1,101 @@
+# ----------------------------
+# pgPool-II configuration file
+# ----------------------------
+#
+# Docs: https://www.pgpool.net/docs/latest/en/html/configuring-pgpool.html#:~:text=conf%20is%20the%20main%20configuration,%24prefix%2Fetc%2Fpgpool.
+
+#------------------------------------------------------------------------------
+# BACKEND CLUSTERING MODE
+#------------------------------------------------------------------------------
+
+backend_clustering_mode = 'streaming_replication'
+
+
+#------------------------------------------------------------------------------
+# CONNECTIONS
+#------------------------------------------------------------------------------
+
+# - pgpool Connection Settings -
+
+listen_addresses = '*'
+port = 5432
+
+# - pgpool Communication Manager Connection Settings -
+
+pcp_listen_addresses = 'localhost'
+pcp_port = 9898
+
+# - Backend Connection Settings -
+
+backend_hostname0 = 'primary'
+backend_port0 = 5432
+backend_weight0 = 1
+backend_data_directory0 = '/var/lib/postgresql/data'
+backend_flag0 = 'ALLOW_TO_FAILOVER'
+backend_application_name0 = 'primary'
+
+backend_hostname1 = 'secondary'
+backend_port1 = 5432
+backend_weight1 = 1
+backend_data_directory1 = '/var/lib/postgresql/data'
+backend_flag1 = 'ALLOW_TO_FAILOVER'
+backend_application_name1 = 'secondary'
+
+# - Authentication -
+
+enable_pool_hba = on
+
+# - SSL Connections -
+
+#------------------------------------------------------------------------------
+# LOGS
+#------------------------------------------------------------------------------
+
+# - Where to log -
+log_per_node_statement = on
+
+
+#------------------------------------------------------------------------------
+# LOAD BALANCING MODE
+#------------------------------------------------------------------------------
+
+load_balance_mode = on
+
+
+#------------------------------------------------------------------------------
+# STREAMING REPLICATION MODE
+#------------------------------------------------------------------------------
+
+# - Streaming -
+
+sr_check_period = 2
+sr_check_user = 'postgres'
+sr_check_password = '${POSTGRES_PASSWORD}'
+sr_check_database = 'postgres'
+
+
+#------------------------------------------------------------------------------
+# HEALTH CHECK GLOBAL PARAMETERS
+#------------------------------------------------------------------------------
+
+health_check_period = 30
+health_check_timeout = 20
+health_check_user = 'postgres'
+health_check_password = '${POSTGRES_PASSWORD}'
+health_check_database = 'postgres'
+health_check_max_retries = 3
+health_check_retry_delay = 10
+
+#------------------------------------------------------------------------------
+# FAILOVER AND FAILBACK
+#------------------------------------------------------------------------------
+failover_command = 'PGPASSWORD=${POSTGRES_PASSWORD} psql --host secondary -U postgres -c "SELECT pg_promote();"'
+failover_on_backend_error = on
+failover_on_backend_shutdown = on
+detach_false_primary = on
+
+#------------------------------------------------------------------------------
+# ONLINE RECOVERY
+#------------------------------------------------------------------------------
+
+auto_failback = on

pgpool2/pgpool2/pool_hba.conf

@@ -0,0 +1,9 @@
+# https://www.pgpool.net/docs/latest/en/html/auth-pool-hba-conf.html
+
+# "local" is for Unix domain socket connections only
+local   all         all                               trust
+# IPv4 local connections:
+host    all         all         127.0.0.1/32          trust
+host    all         all         ::1/128               trust
+
+host all all all scram-sha-256

pgpool2/pgpool2/pool_passwd.tpl

@@ -0,0 +1 @@
+postgres:TEXT${POSTGRES_PASSWORD}