Updating Solr - Overright Configs?

[Spadez <ja...@hotmail.com>]

Hi,

I am writing a bash script which will install SOLR. I had two quick
questions:

Is there a way to update SOLR, changing only the files which have changed
from the previous version, or is it a case that I need to fully uninstall
the old version and then reinstall the newest version.

Secondly, when I update SOLR to the newest version, will it overwrite my
configs? I.e would I have to re-edit my configuration files, or does the
update leave these alone.

Thank you,

James


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Re: Updating Solr - Overright Configs?

[Shawn Heisey <so...@elyograg.org>]

On 3/28/2012 6:04 AM, Spadez wrote:
> I am writing a bash script which will install SOLR. I had two quick
> questions:
>
> Is there a way to update SOLR, changing only the files which have changed
> from the previous version, or is it a case that I need to fully uninstall
> the old version and then reinstall the newest version.
>
> Secondly, when I update SOLR to the newest version, will it overwrite my
> configs? I.e would I have to re-edit my configuration files, or does the
> update leave these alone.

Solr is not truly what one could call an application.  The server 
program requires a servlet container.  It happens to come with one in 
its example setup - Jetty, but that's not the only one, and probably not 
even the most popular.  Tomcat is already heavily used for other things, 
and a lot of people use what is familiar.  My setup uses the included 
Jetty, but my overall setup is highly customized.  I've written my own 
init script that only works for my install, because the way I did things 
will not work for everyone.  One size does not fit all.

Writing an install/upgrade script that would work for other people would 
be a monumental task, so in the rest of what I am saying, I will assume 
that you are just writing this for you, and start with the standard Solr 
answer that usually applies to any question: It depends.

Upgrading Solr itself basically will amount to these steps, assuming 
your container doesn't have a way to automate it:
1) Stop the container (Jetty, Tomcat, etc.).
2) Erase all the data extracted from the previous solr.war file.
  2.a) For the example Jetty, this happens in the "work" directory.
3) Overwrite the solr.war file with the new one.
4) Update any associated jars in included lib folders.
5) Start the container.

Step 4 makes it particularly hard to script.  Not impossible, but there 
are a lot of possible jars and filenames, which can vary from version to 
version.

When it comes to config files, I would recommend against having your 
script do anything here.  The chances of the example schema.xml, 
solrconfig.xml, and other config files (as a set) being useful for any 
production setup is pretty much zero.  If you are upgrading minor 
versions (3.4 to 3.5, for example), chances are good that your config 
will work with absolutely no changes.  That said, your setup probably 
will benefit from some minor changes relating to improvements or changes 
since your previous version.  If you are upgrading major versions, you 
may want to start over from scratch and make new config files to get the 
most benefit.

Unless you are truly a scripting wizard and you've had WAY too many 
redbulls, your script will not be able to modify your config for an 
upgrade, and you'd have to have a custom script for each version.  
Except when I upgraded from 1.4 to 3.2, the new Solr has worked with my 
previous config, but I've always gotten some benefit from minor config 
changes, and I've had to do some research to find out what those changes 
are.

Thanks,
Shawn