Varnish probe thinks web is down if he gets 103 http code

More-Stars · 2021-09-08 07:39:08

Hi,

This is my first post in this forum and I will say that I am sorry for all the mistakes that I will make in this post. This is a desperate call for help as I was not able to find any kind of information on my problem. I am only 20 years old and i just started learning linux 2 years ago. I have a server setup with apache (a verry old version), nginx and varnish. The varnish has a health probe for the web and it probes the status of a custom sterver_status php. it works perfectly fine most of the time but sometimes, the server_status.php will return a 103 status code.

This status code of 103 will trick the probe into thinking the web is sick and for 10-15 seconds, the backend server will return 502. I did some digging and sow that 103 is for early hints and that it comes from apache. I was also able to see that apache will need http2 in order to return 103 codes but as I said, I do not have http2. This appache is too old to know what http2 is.

This is what I get for that probe check:
- - [07/Sep/2021:11:19:38 +0300] "GET /server_status/index.php HTTP/1.1" 103 347 "-" "-"
- - [07/Sep/2021:11:19:38 +0300] "GET /server_status/index.php HTTP/1.1" 103 347 "-" "-"
- - [07/Sep/2021:11:19:40 +0300] "GET /server_status/index.php HTTP/1.1" 103 347 "-" "-"
- - [07/Sep/2021:11:19:41 +0300] "GET /server_status/index.php HTTP/1.1" 103 347 "-" "-"
- - [07/Sep/2021:11:20:06 +0300] "GET /server_status/index.php HTTP/1.1" 103 347 "-" "-"
- - [07/Sep/2021:11:20:06 +0300] "GET /server_status/index.php HTTP/1.1" 103 347 "-" "-"

How can I troubleshoot this and find a solution. I was not able to find anything on google about this problem. If anyone can direct me to the resources that I need in order to find a solution, that will be awesome!!

Thank you very much,
Alexandru.

Slithery · 2021-09-08 10:51:21

Are you using Arch Linux?
It doesn't sound like it if you are using and old version of Apache.

More-Stars · 2021-09-08 11:15:37

Yes, I do use Arch and this is indeed an old version of apache but I do not know exactly the version and I do not have access to that server today.

What I just want to do is to find a way to make that probe ignore 103 codes or just remove them compleatly.

seth · 2021-09-08 13:57:54

https://github.com/varnishcache/varnish … -463191481
Edit: false positive.

Edit #2: you can obviously disable early hints in *your* apache instance, https://httpd.apache.org/docs/2.4/howto … earlyhints

Last edited by seth (2021-09-08 14:07:18)

More-Stars · 2021-09-08 14:21:20

I was able to connect to the server and as I can see, the apach version is 2.2 which does not support mod_http2 and early hints is part of that mod.

This is why I do not understand the reason 103 codes end in my server_status.

seth · 2021-09-08 14:28:31

Why and how are you using a 7+ years old apache??
Also this predates rfc8297 by at least three years - something™ else (proxy?) is responding or your analysis of the situation is flawed.

Arch Linux

#1 2021-09-08 07:39:08

Varnish probe thinks web is down if he gets 103 http code

#2 2021-09-08 10:51:21

Re: Varnish probe thinks web is down if he gets 103 http code

#3 2021-09-08 11:15:37

Re: Varnish probe thinks web is down if he gets 103 http code

#4 2021-09-08 13:57:54

Re: Varnish probe thinks web is down if he gets 103 http code

#5 2021-09-08 14:21:20

Re: Varnish probe thinks web is down if he gets 103 http code

#6 2021-09-08 14:28:31

Re: Varnish probe thinks web is down if he gets 103 http code

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