Passive health check in stream_proxy module

How does passive health check work in stream_proxy module? especially
for
UDP which is connectionless. How does nginx detect if it is a failed
connection and retry next?

Thanks!
Frank

Hi, HTTP Load Balancing | NGINX Documentation

2016-06-08 0:03 GMT+03:00 Frank L. [email protected]:

I checked that page before sending the email.
The “Passive Health Monitoring” section of that page wasn’t clear on how
nginx would consider a “failed attempt”, especially in case of UDP where
there is no “handshake”.

On Tue, Jun 7, 2016 at 3:45 PM, Yuriy M. [email protected]

Hi Frank,

On Tue, Jun 07, 2016 at 04:16:39PM -0700, Frank L. wrote:

2016-06-08 0:03 GMT+03:00 Frank L. [email protected]:

How does passive health check work in stream_proxy module? especially for
UDP which is connectionless. How does nginx detect if it is a failed
connection and retry next?

There are two types of such errors.

If proxy_responses is not zero, ICMP Destination Unreachable signals a
UDP
error. This results in socket read error.

If proxy_responses is not default, proxy_timeout expiration is
considered a UDP
connection error too.


Roman A.