5 ms·

Zero-downtime Deployment (and Rollback) in Tomcat; a walkthrough and a checklist

42 points by javacodegeeks 15y ago

davidw 15y ago
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.
mgkimsal 15y ago
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?
- gaius 15y ago
  all situations except for DB schema changes For that there is Edition-based Redefinition: http://www.oracle.com/technetwork/database/features/availability/edition-based-redefinition-1-133045.pdf http://www.oracle.com/technetwork/database/features/availabi... (2009)
- hboon 15y ago
  Same trick. Configure the proxy to forward to a static page instead of Tomcat.
yock 15y ago
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.
dabeeeenster 15y ago
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!
mgl 15y ago
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/ http://www.zeroturnaround.com/jrebel/features/
- jfager 15y ago
  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.

42 points by javacodegeeks 15y ago

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.

mgkimsal 15y ago

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?

gaius 15y ago
all situations except for DB schema changes For that there is Edition-based Redefinition: http://www.oracle.com/technetwork/database/features/availability/edition-based-redefinition-1-133045.pdf http://www.oracle.com/technetwork/database/features/availabi... (2009)
hboon 15y ago
Same trick. Configure the proxy to forward to a static page instead of Tomcat.

yock 15y ago

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.

dabeeeenster 15y ago

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!

mgl 15y ago

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/ http://www.zeroturnaround.com/jrebel/features/

jfager 15y ago
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.