I was able to resolve this issue by setting the phd.user setting in phabricator to the 'daemon' user. Still sporadically getting errors like the following:
[08-Jan-2020 15:43:14 America/Los_Angeles] [2020-01-08 15:43:14] EXCEPTION: (PhutilProxyException) Error while updating the "rPDT" repository. {>} (CommandException) Command failed with error #255!
COMMAND
'/opt/bitnami/apps/phabricator/htdocs/bin/repository' update -- 'rPDT'
STDOUT
(empty)
STDERR
[2020-01-08 15:43:14] EXCEPTION: (PhabricatorClusterStrandedException) Unable to establish a connection to any database host (while trying "bitnami_phabricator_config"). All masters and replicas are completely unreachable.
AphrontConnectionQueryException: Attempt to connect to bn_phabricator@127.0.0.1 failed with error #1040: Too many connections. at [<phabricator>/src/infrastructure/storage/lisk/PhabricatorLiskDAO.php:177]
arcanist(head=stable, ref.stable=8b5fbb5a1346), phabricator(head=stable, ref.stable=9d644f1bfea1), phutil(head=stable, ref.stable=1750586fdc50)
#0 PhabricatorLiskDAO::raiseUnreachable(string, AphrontConnectionQueryException) called at [<phabricator>/src/infrastructure/storage/lisk/PhabricatorLiskDAO.php:134]
#1 PhabricatorLiskDAO::newClusterConnection(string, string, string) called at [<phabricator>/src/infrastructure/storage/lisk/PhabricatorLiskDAO.php:72]
#2 PhabricatorLiskDAO::establishLiveConnection(string) called at [<phabricator>/src/infrastructure/stor... (1,354 more bytes) ... at [<phutil>/src/future/exec/ExecFuture.php:380]
[08-Jan-2020 15:43:14 America/Los_Angeles] arcanist(head=stable, ref.stable=8b5fbb5a1346), phabricator(head=stable, ref.stable=9d644f1bfea1), phutil(head=stable, ref.stable=1750586fdc50)
[08-Jan-2020 15:43:14 America/Los_Angeles] #0 <#3> ExecFuture::resolvex() called at [<phabricator>/src/applications/repository/daemon/PhabricatorRepositoryPullLocalDaemon.php:480]
[08-Jan-2020 15:43:14 America/Los_Angeles] #1 phlog(PhutilProxyException) called at [<phabricator>/src/applications/repository/daemon/PhabricatorRepositoryPullLocalDaemon.php:487]
[08-Jan-2020 15:43:14 America/Los_Angeles] #2 PhabricatorRepositoryPullLocalDaemon::resolveUpdateFuture(PhabricatorRepository, ExecFuture, integer) called at [<phabricator>/src/applications/repository/daemon/PhabricatorRepositoryPullLocalDaemon.php:256]
[08-Jan-2020 15:43:14 America/Los_Angeles] #3 PhabricatorRepositoryPullLocalDaemon::run() called at [<phutil>/src/daemon/PhutilDaemon.php:219]
[08-Jan-2020 15:43:14 America/Los_Angeles] #4 PhutilDaemon::execute() called at [<phutil>/scripts/daemon/exec/exec_daemon.php:131]
[08-Jan-2020 15:43:19 America/Los_Angeles] [2020-01-08 15:43:19] EXCEPTION: (PhabricatorClusterImpossibleWriteException) Unable to connect to master database ("bitnami_phabricator_drydock"). This is a severe failure; your request did not complete. at [<phabricator>/src/infrastructure/storage/lisk/PhabricatorLiskDAO.php:147]
[08-Jan-2020 15:43:19 America/Los_Angeles] arcanist(head=stable, ref.stable=8b5fbb5a1346), phabricator(head=stable, ref.stable=9d644f1bfea1), phutil(head=stable, ref.stable=1750586fdc50)
[08-Jan-2020 15:43:19 America/Los_Angeles] #0 PhabricatorLiskDAO::raiseImpossibleWrite(string) called at [<phabricator>/src/infrastructure/storage/lisk/PhabricatorLiskDAO.php:97]
[08-Jan-2020 15:43:19 America/Los_Angeles] #1 PhabricatorLiskDAO::newClusterConnection(string, string, string) called at [<phabricator>/src/infrastructure/storage/lisk/PhabricatorLiskDAO.php:72]
[08-Jan-2020 15:43:19 America/Los_Angeles] #2 PhabricatorLiskDAO::establishLiveConnection(string) called at [<phabricator>/src/infrastructure/storage/lisk/LiskDAO.php:841]
[08-Jan-2020 15:43:19 America/Los_Angeles] #3 LiskDAO::establishConnection(string) called at [<phabricator>/src/applications/drydock/garbagecollector/DrydockLogGarbageCollector.php:18]
[08-Jan-2020 15:43:19 America/Los_Angeles] #4 DrydockLogGarbageCollector::collectGarbage() called at [<phabricator>/src/infrastructure/daemon/garbagecollector/PhabricatorGarbageCollector.php:115]
[08-Jan-2020 15:43:19 America/Los_Angeles] #5 PhabricatorGarbageCollector::runCollector() called at [<phabricator>/src/infrastructure/daemon/workers/PhabricatorTriggerDaemon.php:373]
[08-Jan-2020 15:43:19 America/Los_Angeles] #6 PhabricatorTriggerDaemon::updateGarbageCollection() called at [<phabricator>/src/infrastructure/daemon/workers/PhabricatorTriggerDaemon.php:339]
[08-Jan-2020 15:43:19 America/Los_Angeles] #7 PhabricatorTriggerDaemon::runGarbageCollection(integer) called at [<phabricator>/src/infrastructure/daemon/workers/PhabricatorTriggerDaemon.php:109]
[08-Jan-2020 15:43:19 America/Los_Angeles] #8 PhabricatorTriggerDaemon::run() called at [<phutil>/src/daemon/PhutilDaemon.php:219]
[08-Jan-2020 15:43:19 America/Los_Angeles] #9 PhutilDaemon::execute() called at [<phutil>/scripts/daemon/exec/exec_daemon.php:131]