

Zero-downtime Deployment (and Rollback) in Tomcat; a walkthrough and a checklist - javacodegeeks
http://www.javacodegeeks.com/2011/06/zero-downtime-deployment-and-rollback.html

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mgkimsal
This seems like it'd be useful for almost all situations except for DB schema
changes.

Those of you using Tomcat JEE apps, and deal with downtime, how do you handle
putting up some sort of "we're down" page? What strategies do you use?

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gaius
_all situations except for DB schema changes_

For that there is Edition-based Redefinition:
[http://www.oracle.com/technetwork/database/features/availabi...](http://www.oracle.com/technetwork/database/features/availability/edition-
based-redefinition-1-133045.pdf) (2009)

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dabeeeenster
I can't find any documentation about this at all - is there a link anywhere
that describes it in more detail? Nothing on the apache site that I can
find...

Great feature, but it's not a feature until it's documented!

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davidw
Sounds kind of like what Erlang has had for years.

Truth be told though, I think a tiny bit of downtime to restart is perhaps not
as important as many other considerations for _many_ web apps.

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mgl
There is another rather well-established solution to the problem of
redeploying any Java applications (either web profile only or full blown
enterprise edition) and it is JRebel from ZeroTurnaround - have a look, quite
interesting: <http://www.zeroturnaround.com/jrebel/features/>

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jfager
They're different problems. This is about running two versions of a web
application concurrently and migrating clients from old to new gracefully,
without bringing down the site. JRebel is about hot-swapping the bytecode
that's loaded into the JVM.

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yock
This feature has been one of the persistent justifications in my organization
for spending money on Weblogic 10 for a time period unknown to me. Seeing this
in Tomcat makes me hopeful for a world free of application servers...someday.

