backport support for unix domain sockets

[Ken Dreyer (Red Hat)]

Background: Ceph's RADOS Gateway ("RGW") is a web application that provides an S3- and Swift-compatible interface to Ceph. RGW uses mod_proxy_fcgi in Apache 2.4.

In the Ceph team's testing, the RGW application performs much better when using Unix Domain Sockets with mod_proxy_fcgi. On older versions of Apache that do not support Unix Domain Sockets, RGW must use TCP sockets instead, which do not perform as well.

The upstream Apache project shipped Unix Domain Socket support in version 2.4.9. Since Ubuntu Trusty has Apache 2.4.7, I'd like to request that the Ubuntu Apache maintainers backport Unix Domain Socket support into their 2.4.7 package.

(Here is some background information posted to ceph-devel: http://thread.gmane.org/gmane.comp.file-systems.ceph.devel/22552 )

[Ken Dreyer (Red Hat) (kdreyer-redhat)]

Here's the patch that Red Hat ships to provide UDS support for their httpd 2.4.6 package on RHEL 7. (This patch can be found in CentOS' git repository, https://git.centos.org/log/!rpms!httpd.git/refs!heads!c7 )

[Ubuntu Foundations Team Bug Bot (crichton)]

The attachment "Red Hat's patch for UDS support in httpd 2.4.6" seems to be a patch. If it isn't, please remove the "patch" flag from the attachment, remove the "patch" tag, and if you are a member of the ~ubuntu-reviewers, unsubscribe the team.

[This is an automated message performed by a Launchpad user owned by ~brian-murray, for any issues please contact him.]

[Robie Basak (racb)]

Thank you for taking the time to file this.

Normally this would not be possible as it would be a violation of our stable release update policy (https://wiki.ubuntu.com/StableReleaseUpdates). Alternatives could be the backports process (https://wiki.ubuntu.com/UbuntuBackports) or to use a non-LTS release or wait for the next one.

But in this case this might warrant an exception, which would need approval from our Technical Board. I'm just waiting for a decision from my tech lead on whether we want to drive this.

[Rolf Leggewie (r0lf)]

assigning Robie to update the status as the information becomes available (which is the next step for this ticket)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Janne Snabb (snabb)]

Before applying this patch, please note that it has a regression in ProxyPass connectiontimeout parameter handling, see https://bugzilla.redhat.com/show_bug.cgi?id=1242416

[Grant Slater (firefishy)]

Resolved link to the UDS patch: https://git.centos.org/blob/!rpms!httpd.git/6f7de23710cf2fb30178692d962a51a8252842f6/SOURCES!httpd-2.4.6-uds.patch

[Guy Baconniere (lordbaco)]

https://httpd.apache.org/docs/trunk/mod/mod_proxy_fcgi.html

14.04 LTS has Apache 2.4.7 so you cannot use this :

<FilesMatch "\.php$">
    # Requires Apache 2.4.9 or later
    SetHandler "proxy:unix:/var/run/php5-fpm.sock|fcgi://localhost/"

    # Requires Apache 2.4.10 and later
    SetHandler "proxy:fcgi://127.0.0.1:9000"
</FilesMatch>

So with 14.04 LTS you need to
1. Configure each VirtualHost with
   ProxyPassMatch ^/(.*\.php(/.*)?)$ fcgi://127.0.0.1:9000/your_path_to/htdocs/$1
2. In PHP5-FPM, use TCP instead of Unix Domain Socket (/etc/php5/fpm/pool.d/www.conf)
   listen = 127.0.0.1:9000

The alternative is to use mod_fastcgi but it's part of multiverse
(disabled by default /etc/apt/sources.list)

See also
http://events.linuxfoundation.org/sites/events/files/slides/AC2014-FastCGI.pdf

16.04 LTS is out but not all PHP applications are compatible with PHP 7
(like ibm_db2 is not yet ready https://bugs.php.net/bug.php?id=69852)

[Ken Dreyer (Red Hat) (kdreyer-redhat)]

We're going to remove support for FCGI in RGW: http://tracker.ceph.com/issues/16784, so we won't need this bug any more.

[Robie Basak (racb)]

Thanks. Let's close the bug then, so it's clear that nobody is expecting this to ever happen in Trusty. The bug is valid, so rather than Invalid I'll mark it Won't Fix (as we don't intend to fix it).

This isn't intended to exclude anyone else doing it. If you want to work on this, please raise it in this bug and we can reopen, though it would still be subject to SRU team approval, etc.