Enable WAL replication on postgres 10

README.md

Setup master server:

Create a user for the replication:

$ psql postgres
postgres=# CREATE USER replica REPLICATION LOGIN ENCRYPTED PASSWORD 'so-secret';

Change your postgres.conf:

$ sudo vim /etc/postgresql/10/main/postgresql.conf

Set this:

listen_addresses = '*'
wal_level = replica
max_wal_senders = 3
wal_keep_segments = 64

Change your pg_hba.conf:

$ sudo vim /etc/postgresql/10/main/pg_hba.conf

Add at the end of the file:

host    replication     replica      <slave-ip-address>/32            md5

Restart your master server:

$ sudo systemctl restart postgresql

Setup slave server:

Stop postgres server:

$ sudo systemctl stop postgresql

As postgres user:

$ sudo -i
$ su - postgres
$ rm -rf /var/lib/postgresql/10/main/*
$ pg_basebackup -h <master-ip-address> -D /var/lib/postgresql/10/main/ -P -U replica --wal-method=stream
Password: so-secret
$ vim /var/lib/postgresql/10/main/recovery.conf

Add this:

standby_mode          = 'on'
primary_conninfo      = 'host=<master-ip-address> port=5432 user=replica password=so-secret'
trigger_file          = '/tmp/MasterNow'

Start postgres:

$ sudo systemctl start postgresql