I suggest you proxy traffic to an upstream group, and then use
failure/timeout parameters there with proper tuning to retry requests on
the second upstream in case the first in the list fails.
​It will have an overhead if the 1st entry of the upstream group is invalid
on initial connection, but hopefully the 'down' status will help limiting
that overhead on average.​
---
*B. R.*

On Wed, Feb 22, 2017 at 5:08 PM, Kilian Ries <mail@kilian-ries.de> wrote:

> No they cannot be the same (sadly) because i dont't know how the upstream
> is serving the content. Think of a situation where i am not in control of
> the upstream backends and they may change from http to https over time.
> ------------------------------
> *Von:* nginx <nginx-bounces@nginx.org> im Auftrag von Cox, Eric S <
> eric.cox@kroger.com>
> *Gesendet:* Mittwoch, 22. Februar 2017 15:58:26
> *An:* nginx@nginx.org
> *Betreff:* RE: Nginx multiple upstream with different protocols
>
>
> If you are SSL on the frontend (server directive) why would you want to
> proxy between ssl/non-ssl on the upstreams? Can they not be the same? I
> don’t get what you are trying to solve?
>
>
>
> *From:* nginx [mailto:nginx-bounces@nginx.org] *On Behalf Of *Kilian Ries
> *Sent:* Wednesday, February 22, 2017 9:55 AM
> *To:* nginx@nginx.org
> *Subject:* Nginx multiple upstream with different protocols
>
>
>
> Hi,
>
>
>
> i'm trying to setup two Nginx upstreams (one with HTTP and one with HTTPS)
> and the proxy_pass module should decide which of the upstreams is serving
> "valid" content.
>
>
>
> The config should look like this:
>
>
>
> upstream proxy_backend {
>
> server xxx.xx.188.53;
>
> server xxx.xx.188.53:443;
>
> }
>
>
>
> server {
>
> listen 443 ssl;
>
> ...
>
> location / {
>
> proxy_pass http://proxy_backend
> https://urldefense.proofpoint.com/v2/url?u=http-3A__proxy-5Fbackend&d=DwMFAw&c=WUZzGzAb7_N4DvMsVhUlFrsw4WYzLoMP5bgx2U7ydPE&r=20GRp3QiDlDBgTH4mxQcOIMPCXcNvWGMx5Y0qmfF8VE&m=ggR0dMpbDQRqzdhj1Aoq_FUpo8iYplzYiTPyRlQMs9Y&s=wcDWb0xGOKhBVtan1kM5-AVvxNT0ZMnUT9r-yLbyjAQ&e=
> ;
>
> #proxy_pass https://proxy_backend
> https://urldefense.proofpoint.com/v2/url?u=https-3A__proxy-5Fbackend&d=DwMFAw&c=WUZzGzAb7_N4DvMsVhUlFrsw4WYzLoMP5bgx2U7ydPE&r=20GRp3QiDlDBgTH4mxQcOIMPCXcNvWGMx5Y0qmfF8VE&m=ggR0dMpbDQRqzdhj1Aoq_FUpo8iYplzYiTPyRlQMs9Y&s=ztdy1u_d7Ag0QPBnpk1R-LazdfexcrTnljKLZet4VFA&e=
> ;
>
> }
>
> }
>
>
>
>
>
> The Problem is that i don't know if the upstream is serving the content
> via http or https. Is there any possibility to tell nginx to change the
> protocol from the proxy_pass directive? Because if i set proxy_pass to
> https, i get an error (502 / 400) if the upstream website is running on
> http and vice versa.
>
>
>
> So i'm searching for a way to let Nginx decide if he should proxy_pass via
> http or https. Can anybody help me with that configuration?
>
>
>
> Thanks
>
> Greets
>
> Kilian
>
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