Engineering, it turns out, is all about finding the right trade-offs for the task at hand.
When we started working on LiveRebel, we felt that instant updates were a fair trade in exchange for some CPU and memory overhead. With 2.x release, our dream changed from just helping you out with your Java application updates, to driving composite or multi-platform app releases across multiple environments. In that context, the trade-off made less sense.
As LiveRebel evolves into managing multiple environments and platforms, it isn’t useful to focus on technology that is only applicable to a subset of Java application updates. Hotpatching is fantastic in niche cases, but in the context of managing the whole stack it often makes more sense to use the slower strategy of rolling restarts (i.e. the cluster dance) if it means that no overhead is imposed on the application.
So that’s why with LiveRebel 2.6 – launching on March 13 – we will disable the Hotpatching capability by default. This means that all servers will start with zero overhead, and LiveRebel will not offer a Hotpatching strategy for application updates out of the box.
The good news is that if you still want to use the Hotpatching approach, e.g. within your QA environment or in any other environment where performance isn’t critical, you can still enable it on a per-server basis (in server details):
Or if you want to enable it globally, for all servers, it looks like this:
So, in addition to all the management experience improvements in LiveRebel 2.6, we will also commit to an awesome, zero-downtime approach to updating apps with LiveRebel – rolling restarts. We fine-tuned it in this release to be faster and more resilient. The rolling restart strategy guarantees that users will not see your application going down during updates.
I encourage you to try LiveRebel for managing your application, DB and environment updates across different platforms for free (up to 2 servers). If you have any questions, please let us know in the comments section below or @liverebel on Twitter.