title: How to run airflow webserver on port 80
body: <p>When I set airflow webserver to run on port 80, the service is not executed and fails with following error:</p>
  
  <pre><code>...
  [2017-08-30 06:26:35,286] {__init__.py:57} INFO - Using executor CeleryExecutor
  [2017-08-30 06:26:35,421] {driver.py:120} INFO - Generating grammar tables from /usr/lib/python3.5/lib2to3/Grammar.txt
  [2017-08-30 06:26:35,463] {driver.py:120} INFO - Generating grammar tables from /usr/lib/python3.5/lib2to3/PatternGrammar.txt
  [2017-08-30 06:26:35 +0000] [9401] [INFO] Starting gunicorn 19.3.0
  [2017-08-30 06:26:35 +0000] [9401] [ERROR] Retrying in 1 second.
  [2017-08-30 06:26:36 +0000] [9401] [ERROR] Retrying in 1 second.
  [2017-08-30 06:26:37 +0000] [9401] [ERROR] Retrying in 1 second.
  [2017-08-30 06:26:38 +0000] [9401] [ERROR] Retrying in 1 second.
  [2017-08-30 06:26:39 +0000] [9401] [ERROR] Retrying in 1 second.
  [2017-08-30 06:26:40 +0000] [9401] [ERROR] Can't connect to ('0.0.0.0', 80)
  ...
  </code></pre>
  
  <p>Using systemd on Ubuntu 16.04 hosted on AWS. The whole setup works well if run on port 8080.</p>
  
  <p>Relevant config part:</p>
  
  <pre><code>$ grep web_server_port /home/ubuntu/airflow/airflow.cfg
  web_server_port = 80
  </code></pre>
  
  <p>Service configuration:</p>
  
  <pre><code>$ cat /usr/lib/systemd/system/airflow-webserver.service 
  [Unit]
  Description=Airflow webserver daemon
  After=network.target postgresql.service mysql.service redis.service rabbitmq-server.service
  Wants=postgresql.service mysql.service redis.service rabbitmq-server.service
  
  [Service]
  User=ubuntu
  Group=ubuntu
  Type=simple
  ExecStart=/usr/local/bin/airflow webserver --pid /home/ubuntu/airflow/webserver.pid
  Restart=on-failure
  RestartSec=5s
  PrivateTmp=true
  
  [Install]
  WantedBy=multi-user.target
  </code></pre>