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From Kohei Nozaki <>
Subject Re: Advice for using roller in an AWS autoscaling environment
Date Tue, 26 May 2015 22:19:07 GMT
I don't know very well about AWS autoscaling, but I guess there are some 
additional things need to be cleared to get Roller work on clustered 

* Second level cache of JPA: need to be turned off, or cluster-aware 
configuration is needed.

* Page cache: Roller saves rendered htmls as a cache. when an 
administrator, author or visitor made a change (e.g. posting a new 
entry), caches of some pages are need to be invalidated. but I'm not 
sure how to invalidate it among servers.

* Salt processing: to prevent XSRF, Roller uses salt value 
authentication for every POST requests on administration pages but 
out-of-box Roller saves SaltCache as a static variable, so every POST 
requests need to be sent to a particular server for a particular client. 
perhaps a some kind of new implementation which uses memcached is needed 
as mentioned in a comment of

And of course, http sessions need to be replicated among servers for 
administration pages and comment authenticators.


On 5/27/15 1:43, Dave wrote:
> Hi Sean,
> You are right, uploaded files will be a problem. I'm not aware of a
> solution that does not require new code, except for something like NFS.
> Another thing to watch out for is the search index. Roller uses Lucene
> directly, which means each instance of Roller will have it's own Lucene
> index. As bloggers make changes to posts, indexes may get out of sync and
> search will not work uniformly.
> You could work around this by re-indexing each Roller instance
> periodically. But, unfortunately, I don't think there is a way to trigger a
> re-index of the Roller search index, except for stopping Roller, deleting
> the search index directory then restarting Roller -- Roller will re-index
> all blog entries if no index data is found.  Another work around is to just
> use Google for your site search.
> Hope that helps.
> - Dave
> On Tue, May 26, 2015 at 10:15 AM Sean Pritchard <>
> wrote:
>> Hi,
>> I'd like to use roller in an autoscaled AWS cluster.  It looks like the
>> main hurdle to doing that will be the local media directory that contains
>> uploaded images.  Have any of you tried running roller in such an
>> environment?  Are there alternatives to storing the media files in local
>> storage?  For example in AWS S3?  Are you aware of any other factors that
>> may interfere with running roller in a active-active loadbalanced cluster?
>> Best Regards
>> Sean
>> MilitaryHire - Jobs for Veterans

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