Thermostat 0.3 released

The Thermostat team (Jon, Omair, Mario and myself) are proud to announce Thermostat 0.3, codenamed ‘Not Yet’ (yeah yeah, I know). (For those who don’t know yet, Thermostat is a next generation and free/open source monitoring and diagnosing tool for OpenJDK.)

The major new feature is the support for creating and analysing memory by creating a heapdump and browsing a histogram of objects in memory. Additional features include a kill switch, using which you can terminate a running process (for example if it grossly misbehaves), a new Look and Feel (named Dolphin, made to look similar to Gnome 3’s Adwaita theme), new command line commands to support heap analysis, numerous little UI improvements and bugfixes.

The below screenshot shows the new heap analysis view. It monitors the heap usage of a selected JVM. When you click the big ‘Heap Dump’ button, a heap dump image is created and saved in the MongoDB, it shows up in the list below (you can take and analyze several heapdumps per VM.. they will be listed with the timestamp of their creation). Clicking on the heap dump in that list brings up a histogram view that lists all allocated objects, the number of their instances and the total size of their allocation. This list can be sorted by clicking on the respective table headers. (We are planning several more heap analysis features like searching specific objects and following their paths to GC roots, showing incoming and outgoing references, etc etc, but those will show up in the next release, in about 4 weeks from now.)

Thermostat heap analysis view

This was a fairly important release for us, it was our first milestone release, ready just in time for the Red Hat Summit (Deepak will present Thermostat there). Infact, it is the second milestone, milestone 0 was earlier this year when Jon and Omair showed Thermostat at FOSDEM. We took at lot of care and time to make Thermostat solid and useful, and while it’s not overflowing with features yet, we prepared the ground for a lot of greatness. Eventually, Thermostat will support monitoring remote VMs and whole clusters of VMs, and allow drilling down into problem areas and perform deep and fine grained analysis, utilizing information from the JVM itself as well as from the kernel, the operating system and even from the application server.

Please read the release announcement for more details about this new shiny release of Thermostat!


About Roman Kennke
JVM Hacker, Principal Software Engineer at Red Hat's OpenJDK team, Shenandoah GC project lead, Java Champion

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