1. Change the password_encryption parameter
NOTE
It is possible that managed services (such as RDS/CloudSQL) will require a
different configuration.
2. Regenerate the Vault passwords
3. Change the authentication method in pg_hba.conf
xxxxxxxxxx
# cd /var/lib/pgsql/data
# vim pg_hba.conf
# TYPE DATABASE USER ADDRESS METHOD
# "local" is for Unix domain socket connections only
local all all scram-sha-256
# IPv4 local connections:
host all all 127.0.0.1/32 scram-sha-256
# IPv6 local connections:
host all all ::1/128 scram-sha-256
# Allow replication connections from localhost, by a user with the
# replication privilege.
local replication all scram-sha-256
host replication all 127.0.0.1/32 scram-sha-256
host replication all ::1/128 scram-sha-256