Postgres create database freezes - trying to run with replication

I am trying to create a highly available PostgreSQL database set-up using
the Compose Governor project [https://github.com/compose/governor]

I have three Postgres servers and I want to ensure that full service
remains when two out of three database servers remain online. Having these
systems immediately in synchronisation with each other is of utmost
importance to the application they will serve.

So from what I understand, I'm aiming to do Synchronous Streaming
Replication, where writes to two out of three of the servers is considered
safe.

When the servers come online and when I try and and create a database for
my application, my process hangs and I can't yet understand why or what I
do to fix this.

Systemd reports the following:

# systemctl status governor● governor.service - Governor: A runner to
orchestrate a high-availability PostgreSQL service
Loaded: loaded (/etc/systemd/system/governor.service; enabled; vendor
preset: disabled)
Active: active (running) since Mon 2016-10-31 10:37:42 GMT; 6min ago
Main PID: 11685 (python)
CGroup: /system.slice/governor.service
├─11685 /bin/python /opt/governor/governor.py /etc/governor/config.yml
├─11705 /usr/pgsql-9.6/bin/postgres -D
/var/lib/pgsql/governor/pgsqla -c listen_addresses=192.168.2.111 -c
port=5432 -c hot_standby=on -c synchronous_commit=on -c...
├─11706 postgres: logger process
├─11708 postgres: checkpointer process
├─11709 postgres: writer process
├─11710 postgres: stats collector process
├─11752 postgres: postgres postgres [local] idle
├─11754 postgres: wal writer process
├─11755 postgres: autovacuum launcher process
├─11756 postgres: archiver process last was 000000020000000000000005
├─11809 postgres: wal sender process replicator
192.168.2.112(32852) streaming 0/6000968
├─12025 postgres: postgres postgres [local] CREATE DATABASE
waiting for 0/6000850
└─12050 postgres: wal sender process replicator
192.168.2.113(48000) streaming 0/6000968

The full command string of the postgres process is:

# ps -fwwp 11705

UID PID PPID C STIME TTY TIME CMD
postgres 11705 1 0 10:37 ? 00:00:00
/usr/pgsql-9.6/bin/postgres -D /var/lib/pgsql/governor/pgsqla -c
listen_addresses=192.168.2.111 -c port=5432 -c hot_standby=on -c
synchronous_commit=on -c wal_keep_segments=8 -c wal_level=hot_standby
-c archive_command=mkdir -p ../wal_archive && cp %p ../wal_archive/%f
-c max_wal_senders=5 -c archive_timeout=1800s -c archive_mode=on -c
synchronous_standby_names=2 ( pgsqla, pgsqlb, pgsqlc ) -c
max_replication_slots=5

Postgres reports the following:

postgres=# select * from pg_stat_activity;
datid | datname | pid | usesysid | usename | application_name |
client_addr | client_hostname | client_port | backend_start
| xact_start| query_start |
state_change | wait_event_type | wait_event | state |
backend_xid | backend_xmin |
query
-------+----------+-------+----------+----------+------------------+-------------+-----------------+-------------+-------------------------------+-------------------------------+-------------------------------+-------------------------------+-----------------+------------+--------+-------------+--------------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------13322
| postgres | 11752 | 10 | postgres | |
| | -1 | 2016-10-31 10:37:43.863694+00 ||
2016-10-31 10:40:54.273678+00 | 2016-10-31 10:40:54.273893+00 |
| | idle | | | DO
LANGUAGE plpgsql $$DECLARE somevar VARC
HAR; BEGIN SELECT slot_name INTO somevar FROM pg_replication_slots
WHERE slot_name = 'pgsqlc' LIMIT 1; IF NOT FOUND THEN PERFORM
pg_create_physical_replication_slot('pgsqlc'); E
ND IF; END$$;13322 | postgres | 12025 | 10 | postgres |
| | | -1 | 2016-10-31
10:38:26.715132+00 | 2016-10-31 10:38:26.717104+00| 2016-10-31
10:38:26.717104+00 | 2016-10-31 10:38:26.717105+00 | |
| active | 1756 | | CREATE DATABASE
"database"13322 | postgres | 12184 | 10 | postgres | psql
| | | -1 | 2016-10-31
10:40:34.102113+00 | 2016-10-31 10:40:57.687182+00| 2016-10-31
10:40:57.687182+00 | 2016-10-31 10:40:57.687197+00 | |
| active | | 1756 | select * from
pg_stat_activity;(3 rows)

postgres=# select * from pg_replication_slots;
slot_name | plugin | slot_type | datoid | database | active |
active_pid | xmin | catalog_xmin | restart_lsn |
confirmed_flush_lsn-----------+--------+-----------+--------+----------+--------+------------+------+--------------+-------------+---------------------
pgsqlb | | physical | | | t |
11809 | | | 0/6000888 |
pgsqlc | | physical | | | t |
12050 | | | 0/6000888 |(2 rows)

What can be done to unfreeze this connection and correctly create my
applications database correctly?

Many Thanks,

Adam.