Nginx Solution for AWS Amazon ELB Health Checks - return 200 without IF
I have the following code that is working on Nginx to keep the AWS ELB healthcheck happy.
map $http_user_agent $ignore {
default 0;
"ELB-HealthChecker/1.0" 1;
}
server {
location / {
if ($ignore) {
access_log off;
return 200;
}
}
}
I know the 'IF' is best avoided with Nginx and I wanted to ask if someone would know how to recode this without the 'if'?
thankyou
Solution 1:
Don't overcomplicate things. Just point your ELB health checks at a special URL just for them.
server {
location /elb-status {
access_log off;
return 200;
}
}
Solution 2:
Just to improve on the above answer, which is correct. The following works great:
location /elb-status {
access_log off;
return 200 'A-OK!';
# because default content-type is application/octet-stream,
# browser will offer to "save the file"...
# the next line allows you to see it in the browser so you can test
add_header Content-Type text/plain;
}
Solution 3:
Update: If the user agent validation is necessary,
set $block 1;
# Allow only the *.example.com hosts.
if ($host ~* '^[a-z0-9]*\.example\.com$') {
set $block 0;
}
# Allow all the ELB health check agents.
if ($http_user_agent ~* '^ELB-HealthChecker\/.*$') {
set $block 0;
}
if ($block = 1) { # block invalid requests
return 444;
}
# Health check url
location /health {
return 200 'OK';
add_header Content-Type text/plain;
}