Condor (>= 7.0.2-4) will need to be configured in order to use these job
hooks (ie the low-latency feature).  To configure condor, add the following
lines to your condor_config (default location: /etc/condor) file:

# Startd hooks
LOW_LATENCY_HOOK_FETCH_WORK = $(LIBEXEC)/hooks/hook_fetch_work.py
LOW_LATENCY_HOOK_REPLY_FETCH = $(LIBEXEC)/hooks/hook_reply_fetch.py

# Starter hooks
LOW_LATENCY_HOOK_PREPARE_JOB = $(LIBEXEC)/hooks/hook_prepare_job.py
LOW_LATENCY_HOOK_UPDATE_JOB_INFO = $(LIBEXEC)/hooks/hook_update_job_status.py
LOW_LATENCY_HOOK_JOB_EXIT = $(LIBEXEC)/hooks/hook_job_exit.py

SLOT1_JOB_HOOK_KEYWORD = LOW_LATENCY
STARTD_JOB_HOOK_KEYWORD = LOW_LATENCY
STARTER_JOB_HOOK_KEYWORD = LOW_LATENCY

FetchWorkDelay = ifThenElse(State == "Claimed" && Activity == "Idle", 0, 10)
STARTER_UPDATE_INTERVAL = 30

LL_DAEMON = $(SBIN)/carod
DAEMON_LIST = $(DAEMON_LIST), LL_DAEMON

For more information on Condor/Grid hooks please see:
https://www.cs.wisc.edu/condor/manual/v7.1/4_4Job_Hooks.html

The AMQP translation daemon (carod) will first look for its configuration
in condor's configuration files.  The following parameters can be placed in
a condor configuration file to configure carod:

LL_BROKER_IP:
   Type: IP Address
   Desc: The IP address of the broker that carod should talk to

LL_BROKER_PORT:
   Type: Integer
   Desc: The port on $(LL_BROKER_IP) the broker is listening to

LL_BROKER_QUEUE:
   Type: String
   Desc: The queue on the broker for condor jobs

LL_DAEMON_IP:
   Type: IP Address
   Desc: The IP address of the interface carod use for connections

LL_DAEMON_PORT:
   Type: Integer
   Desc: The port carod should use to listen for connections

LL_DAEMON_QUEUED_CONNECTIONS:
   Type: Integer
   Desc: The number of allowed outstanding connections

LL_DAEMON_LEASE_TIME:
   Type: Integer
   Desc: The maximum amount of time a job is allowed to run without providing
         an update.  This  must be larger than what is set for
         STARTER_UPDATE_INTERVAL.

LL_DAEMON_LEASE_CHECK_INTERVAL:
   Type: Integer
   Desc: How often to check for lease expiration

If the configuration is not found in condor's configuration files, then
carod will look in /etc/condor/carod.conf.

Then edit the job hook configuration file to communicate with carod.
See /usr/share/doc/condor-job-hooks-1.0/INSTALL for details.

Once the configuration is complete, restart condor.

To use the low-latency feature, configure condor as mention aboved, ensure
qpid is running, and start carod.  To submit jobs, send AMQP messages to the
AMQP queue defined in the /etc/condor/carod.conf configuration file, with
the classad information stored as headers in the application_headers field.