Hi all,

After some debugging, I just found the reason for the issue where paste sometimes displayed mailman et vica versa.

Here my explanation on IRC: puiterwijk | So... It turns out that when Varnish computes the hash of a request to see if the "primary" request HTTP headers. These being host, path, method and then take into account anything that's mentioned in the Vary header. puiterwijk | It explicitly does *not* take into consideration any "random" HTTP headers. puiterwijk | And here comes the fun part: in our setup, the "host" header is always localhost because we don't set apache's PreseveHostHeader for *most* sites (I'll come back to this in a minute). puiterwijk | Instead, we send the hostname via X-Forwarded-Host, and we pick the backend based on that... puiterwijk | But since the Host header that Varnish sees is the same between paste and lists requests, it's actually hashing them to the same request object, returning each others responses puiterwijk | The reason this has not impacted any other sites, is because we actually don't depend on just the X-Forwarded-Host header for those requests, but instead use req.url: one of the fields taken into account in the request hash puiterwijk | So, a very simple fix would be to just set PreserveHostHeader in the Apache config (for lists and paste, but maybe for all?). That'd make the host header actually get into the request object hash puiterwijk | Current Status: puiterwijk | OK puiterwijk | Nagios agrees with me that this fixes the problem

Can I get +1s for the fix:

diff --git a/playbooks/include/proxies-reverseproxy.yml b/playbooks/include/proxies-reverseproxy.yml index ac65440..e5720c9 100644 --- a/playbooks/include/proxies-reverseproxy.yml +++ b/playbooks/include/proxies-reverseproxy.yml @@ -70,6 +70,7 @@ localpath: / remotepath: / header_scheme: true + keephost: true proxyurl: "{{ varnish_url }}"

- role: httpd/reverseproxy @@ -78,6 +79,7 @@ localpath: / remotepath: / header_scheme: true + keephost: true proxyurl: "{{ varnish_url }}"

# The place for the raw originals @@ -150,6 +152,7 @@ - role: httpd/reverseproxy website: paste.fedoraproject.org destname: modernpaste + keephost: true proxyurl: "{{ varnish_url }}"

- role: httpd/reverseproxy

Regards, Patrick