Django ALLOWED_HOSTS with ELB HealthCheck
I have a django app deployed on Elastic Beanstalk. HealthCheck is not working for my application because ELB HealthCheck IP is not included in my settings variable ALLOWED_HOSTS
.
How do I change ALLOWED_HOSTS
to pass HealthCheck? I would just pass in an explicit IP, but I believe this changes, so whenever the IP changes change, validation will fail until I add a new IP.
Your EC2 instance can request metadata about itself, including its IP address, which is available at http://169.254.169.254/latest/meta-data/local-ipv4 .
You can check this by ssh-in into your EC2 instance and running:
curl http://169.254.169.254/latest/meta-data/local-ipv4
So, in your configuration, you can do something like:
import requests
ALLOWED_HOSTS = ['.yourdomain.com', ]
try:
EC2_IP = requests.get('http://169.254.169.254/latest/meta-data/local-ipv4').text
ALLOWED_HOSTS.append(EC2_IP)
except requests.exceptions.RequestException:
pass
Obviously you can replace requests
with urllib
if you don't need the dependency.
The other solution doesn't answer the question because it doesn't account for all the various AWS tools (ELB, etc.). What we are done with (since we are using nginx
+ uwsgi
), we are setting the header to something valid when the user makes a request.
As described on this page:
https://opbeat.com/blog/posts/the-new-django-allowed_hosts-with-elb-uwsgi-and-nginx/
We'll post our config nginx
as shown below:
set $my_host $host;
if ($host ~ "\d+\.\d+\.\d+\.\d+") {
set $my_host "example.com";
}
location / {
uwsgi_pass unix:///tmp/mysite.com.sock;
uwsgi_param HTTP_HOST $my_host;
include uwsgi_params;
}
The key here is to put a valid value for $my_host
according to yours ALLOWED_HOSTS
.
Unfortunately, there is no “perfect” solution without increasing overhead. In some configurations, you will need to constantly add IPs to ALLOWED_HOSTS
, but this solution usually works with the smallest head.