PostgreSQL Replication & HA — Docker Examples

Easy Testing

Tiga setup:

1. pg-replication-basic/ → Primary + Replica (belajar/testing, failover manual)
2. pg-cluster-haproxy/ → Primary + Replica + HAProxy (1 endpoint, failover manual)
3. pg-ha/ → Patroni + etcd + HAProxy (auto-failover, read/write split)

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Cara Jalankan

1) Basic

cd pg-replication-basic
docker compose up -d

# Test insert ke primary
docker exec -it pg_primary psql -U postgres -d mydb -c "INSERT INTO test_table(name) VALUES ('hello');"

# Cek data di replica
docker exec -it pg_replica psql -U postgres -d mydb -c "TABLE test_table;"

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2) Cluster + HAProxy

cd pg-cluster-haproxy
docker compose up -d

# Insert lewat HAProxy (port 5000)
PGPASSWORD=postgres psql -h localhost -p 5000 -U postgres -d mydb -c "INSERT INTO test_table(name) VALUES ('from haproxy');"

# Cek data di replica langsung
docker exec -it pg_replica1 psql -U postgres -d mydb -c "TABLE test_table;"

Failover manual: promote replica jika primary mati

docker exec -it pg_replica1 psql -U postgres -d mydb -c "SELECT pg_promote();"

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3) HA dengan Patroni

cd pg-ha
docker compose up -d

# Insert ke leader via HAProxy (port 5000 = write)
PGPASSWORD=postgres psql -h localhost -p 5000 -U postgres -d postgres -c "INSERT INTO test_table(name) VALUES ('from patroni leader');"

# Baca dari replica (port 5001 = read pool)
PGPASSWORD=postgres psql -h localhost -p 5001 -U postgres -d postgres -c "TABLE test_table;"

Test failover otomatis: stop leader

docker stop patroni1

Patroni otomatis promote node lain → HAProxy tetap arahkan backend ke leader baru di port 5000.

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Endpoint

• Basic

  • Primary → localhost:5432
  • Replica → localhost:5433

• Cluster HAProxy

  • Write → localhost:5000

• Patroni HA

  • Write (leader) → localhost:5000
  • Read (replica pool) → localhost:5001
  • HAProxy stats → http://localhost:8404