Apache 2.2.31 and mod_cluster 1.2.6 mismatch

[ck6356]

We have upgraded Apache to v2.2.31 for added security, including more recent openssl packages.  I am receiving the following warning in the Apache err log on startup when loading mod_cluster 1.2.6:

" [warn] httpd version 2.2.31 mismatch detected "

The only information that I was able to find is this older bug notice for Apache 2.2.15: Bug 916387 – mod_cluster 1.2.3.Final with httpd 2.2.15-15 generates confusing warning about version mismatch.  It describes that the mismatch is between Apache and the mod_cluster version.  It is not the same versions of Apache or mod_cluster, but seems to imply that it is not serious, just a reporting issue, and it can be ignored.  Does anyone know if Apache 2.2.31 and mod_cluster 1.2.6 are compatible, and if this warning is correct/serious?  In testing, it was still able to connect and balance to JBoss EAP.  Thanks

[mbabacek]

Dear Chris, you should not, or I would even say must not, use mod_cluster 1.2.6 It is a vastly obsolete version comprising serious performance and CVE issues.

On the issue of mismatch detected: Contrary to what you found on that Bugzilla, it is actually an issue (with that Bugzilla, it was ascertained that it was OK at the time with that particular version). The problem is mod_cluster relies on mod_proxy's internal (private) APIs that could change with any httpd patch or even more likely with a micro updates. To be safe from intermittent Segfaults caused by a different structure sizes, one has to recompile mod_cluster with any new httpd.  It is O.K. for you to use different versions of mod_cluster on Apache HTTP Server side and JBoss AS/Wildfly side -- the protocol they talk to each other with is the same up to mod_cluster 1.3.2.

If you need assistance with recompiling mod_cluster with your particular version of httpd, tell us the operating system and architecture you use and we will be glad to help you.

Cheers

-K-

[ck6356]

Thanks Michal.  Should I be targeting mod_cluster 1.3.2 then for use with my Apache 2.2.31?  I did not move to 1.3.1, because the binaries from here (mod_cluster - Downloads - JBoss Community) would not load (Apache 2.4 compatibility issue).  The source from the same location came with Apache HTTP which I do not need, because I have an existing Apache installation.  I did try looking at the docs for how to compile, and found another source repository here (Tags · modcluster/mod_cluster · GitHub).  I'm not sure of the relationship between each of these repositories. Yes, I would appreciate assistance compiling mod_cluster with httpd.  I am currently using RHEL 6.6 x86 64 bit.  Is there a way to compile just the mod_cluster modules only, as stand-alone, so I can simply add them to an existing Apache installation?  I do not actually manage the Apache for my environment.

[mbabacek]

Dear Chris, there is nothing dodgy about it. git clone, cmake, make...

The following example is an ASCII recorded terminal session that walks one through on Fedora 24: Examples – mod_cluster

Note that cmake build file wasn't part of the older versions. For them, one has to either copy that CMakeLIsts file or use Autotools: Documentation – mod_cluster

Cheers

-K-

[joaocunhalopes]

Hi Michal,

I could use some help compiling mod_cluster 1.3.1 Final for Apache 2.2.31 on Windows 32 bit (x86).

Any chance you can guide me through the compile process?

Thank you.

J

[jfclere]

See Chapter 4. Building mod_cluster from sources

[mbabacek]

This is how you compile on Windows: mod_proxy_cluster/README.md at master · modcluster/mod_proxy_cluster · GitHub

Beware of renaming the repo from mod_cluster to mod_proxy_cluster, so one might to adjust  a name or two in the tutorial.

Cheers

-k-

[mbabacek]

This is probably posted by mistake - it's for Linux and for an obsolete version.