gunicorn.errors.HaltServer: <HaltServer 'Worker failed to boot.' 3> django

run guncorn with --preload can see the error log, like this

gunicorn app:application --preload -b 0.0.0.0:5000 

This will usually give you a more detailed error message.

Actually the problem here was the wsgi file itself, previously before django 1.3 the wsgi file was named with an extension of .wsgi, but now in the recent versions it will be created with and extension of .py that is the wsgi file must be a python module

so the file should be hello_wsgi.py and command should be

gunicorn  hello:application -b xx.xxx.xxx.xx:8000

You didn't show a full output. It probably looks like

$ gunicorn elcarweb.wsgi[2015-10-27 21:01:47 +0000] [5429] [INFO] Starting gunicorn 19.2.1[2015-10-27 21:01:47 +0000] [5429] [INFO] Listening at: http://127.0.0.1:8000 (5429)[2015-10-27 21:01:47 +0000] [5429] [INFO] Using worker: sync[2015-10-27 21:01:47 +0000] [5434] [INFO] Booting worker with pid: 5434[2015-10-27 21:01:47 +0000] [5434] [ERROR] Exception in worker process:Traceback (most recent call last):  File "/home/tomek/Elcar/elcarweb/env/lib/python2.7/site-packages/gunicorn/arbiter.py", line 503, in spawn_worker    worker.init_process()  File "/home/tomek/Elcar/elcarweb/env/lib/python2.7/site-packages/gunicorn/workers/base.py", line 116, in init_process    self.wsgi = self.app.wsgi()  File "/home/tomek/Elcar/elcarweb/env/lib/python2.7/site-packages/gunicorn/app/base.py", line 67, in wsgi    self.callable = self.load()  File "/home/tomek/Elcar/elcarweb/env/lib/python2.7/site-packages/gunicorn/app/wsgiapp.py", line 65, in load    return self.load_wsgiapp()  File "/home/tomek/Elcar/elcarweb/env/lib/python2.7/site-packages/gunicorn/app/wsgiapp.py", line 52, in load_wsgiapp    return util.import_app(self.app_uri)  File "/home/tomek/Elcar/elcarweb/env/lib/python2.7/site-packages/gunicorn/util.py", line 355, in import_app    __import__(module)ImportError: No module named elcarweb.wsgiTraceback (most recent call last):  File "/home/tomek/Elcar/elcarweb/env/lib/python2.7/site-packages/gunicorn/arbiter.py", line 503, in spawn_worker    worker.init_process()  File "/home/tomek/Elcar/elcarweb/env/lib/python2.7/site-packages/gunicorn/workers/base.py", line 116, in init_process    self.wsgi = self.app.wsgi()  File "/home/tomek/Elcar/elcarweb/env/lib/python2.7/site-packages/gunicorn/app/base.py", line 67, in wsgi    self.callable = self.load()  File "/home/tomek/Elcar/elcarweb/env/lib/python2.7/site-packages/gunicorn/app/wsgiapp.py", line 65, in load    return self.load_wsgiapp()  File "/home/tomek/Elcar/elcarweb/env/lib/python2.7/site-packages/gunicorn/app/wsgiapp.py", line 52, in load_wsgiapp    return util.import_app(self.app_uri)  File "/home/tomek/Elcar/elcarweb/env/lib/python2.7/site-packages/gunicorn/util.py", line 355, in import_app    __import__(module)ImportError: No module named elcarweb.wsgi[2015-10-27 21:01:47 +0000] [5434] [INFO] Worker exiting (pid: 5434)Traceback (most recent call last):  File "/home/tomek/Elcar/elcarweb/env/bin/gunicorn", line 11, in <module>    sys.exit(run())  File "/home/tomek/Elcar/elcarweb/env/lib/python2.7/site-packages/gunicorn/app/wsgiapp.py", line 74, in run    WSGIApplication("%(prog)s [OPTIONS] [APP_MODULE]").run()  File "/home/tomek/Elcar/elcarweb/env/lib/python2.7/site-packages/gunicorn/app/base.py", line 189, in run    super(Application, self).run()  File "/home/tomek/Elcar/elcarweb/env/lib/python2.7/site-packages/gunicorn/app/base.py", line 72, in run    Arbiter(self).run()  File "/home/tomek/Elcar/elcarweb/env/lib/python2.7/site-packages/gunicorn/arbiter.py", line 170, in run    self.manage_workers()  File "/home/tomek/Elcar/elcarweb/env/lib/python2.7/site-packages/gunicorn/arbiter.py", line 473, in manage_workers    self.spawn_workers()  File "/home/tomek/Elcar/elcarweb/env/lib/python2.7/site-packages/gunicorn/arbiter.py", line 537, in spawn_workers    time.sleep(0.1 * random.random())  File "/home/tomek/Elcar/elcarweb/env/lib/python2.7/site-packages/gunicorn/arbiter.py", line 210, in handle_chld    self.reap_workers()  File "/home/tomek/Elcar/elcarweb/env/lib/python2.7/site-packages/gunicorn/arbiter.py", line 455, in reap_workers    raise HaltServer(reason, self.WORKER_BOOT_ERROR)gunicorn.errors.HaltServer: <HaltServer 'Worker failed to boot.' 3>

Last trackback is almost the same, but before You see required informations:

ImportError: No module named elcarweb.wsgi

If You see this error, then solution is run gunicorn with --chdir=/your/app/dir parameter.