Why SAM webui gives service temporarily unavailable & katello-jobs service fails?

Issue

• sam fails to start:

# katello-service restart
Shutting down Katello services...
Stopping katello-jobs:                                     [FAILED]
Stopping katello:
Stopping elasticsearch:                                    [  OK  ]
Stopping thumbslug:                                        [  OK  ]
Stopping httpd:                                            [  OK  ]
Stopping tomcat6:                                          [  OK  ]
Done.
Starting Katello services...
Starting tomcat6:                                          [  OK  ]
Starting httpd:                                            [  OK  ]
Starting thumbslug: Oct 16 10:33:39 [main] WARN  org.candlepin.thumbslug.Main - Shutting down...
                                                           [  OK  ]
Starting elasticsearch:                                    [  OK  ]
Starting katello:                                          [  OK  ]
Starting katello-jobs:                                     [FAILED]
Done.
# katello -u admin -p password ping
Service unavailable or restarting, try later
#

• SAM services are not starting up, those are failing to connect pgsql and /var/lib/pgsql/pgstartup.log says,

FATAL:  could not create any TCP/IP sockets
LOG:  could not bind IPv4 socket: Cannot assign requested address
HINT:  Is another postmaster already running on port 5432? If not, wait a few seconds and retry.