Since no one type of clustering satisfies all needs, they have several different clustering tools which take various clustering approaches. The open source projects PostgresXC and Postgres-XL are available, as well as open source forks and proprietary tools such as Greenplum Database, Citus Data and several others.
Also, PostgreSQL is supported by filesystem-based clustering systems for failover, including ones from Red Hat, Microsoft, Veritas and Oracle.
