CODEWITHSUNDEEP
backendvarnish
Sauleil
Sauleil

Reputation: 2603

Varnish seems to have trouble keeping the connection with the backend (error 503)

I've been struggling with this problem in my local environment for quite some time now. I've been looking everywhere trying many different solutions.

Setup: I create a backend in the config file that point on an external web site with no caching (pass).

Behavior: Randomly, the backend connection is closed with the message "Error 503 Service Unavailable".

I have a simple web page served by Amazon EC2. I use Varnish to redirect my calls. I hit F5 in my browser and sometime it works, sometime not. Using varnishlog, I've been trying to figure out what is hapenning: The only thing that make sense is the line where it says "BackendClose ". After that, all subsequent requests fails. (Also, I have other backend configured as well and it works fine.)

Also, I've been trying to play with the keep-alive/session length, but nothing works so far. From what I understand, it seems that the connection to the backend is closed (probably via amazon for some reason), but varnish wait some time before it restores it.

So, if anyone have some suggestions, I would be happy to try them.

Varnish version: varnish-3.0.2 revision cbf1284

Upvotes: 1

Views: 834

Answers (1)

Sauleil
Sauleil

Reputation: 2603

after trying to figure out where the problem came from, I finally figure it out.

It seems that there was something that was blocking the ip for some reason. After checking for a firewall blocking randomly some packets and the different switch policies, I found out that the problem was because I had a second ethernet configuration for my machine. I don't know why it was there so I deleted it. Since then, the issue is gone.

So thanks to the network guys who helped me to fix that, because I was becoming insane :P In the end, it wasn't a Varnish issue. Next time, I'll try to do many different kind of tests on different machines and environment before loosing so much time in something like that.

Upvotes: 0

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