Release Namazu v0.2.0

Note: we recently renamed Earthquake to Namazu.

We are glad to annouce the release of Namazu v0.2.0.


Namazu v0.2.0 includes many new features: Process inspector, Filesystem inspector, Container CLI, Semi-deterministic replaying API…

These new features made Namazu much more powerful and simple. Now, no configuration is needed to get started with Namazu.

You can download the Namazu v0.2.0 binary release from github.

Or you can also build Namazu manually:

$ sudo apt-get install libzmq3-dev libnetfilter-queue-dev
$ go get

New features

Process inspector

The process inspector sets random scheduling priority to threads under a specific Linux process:

$ sudo nmz inspectors proc -pid $TARGET_PID -watch-interval 1s

The process inspector is sometimes useful when you want to reproduce flaky xUnit tests.

The experimental result for Hadoop tests is available in the slide we presented at ApacheCon:

Filesystem inspector

The filesystem inspector provides randomized scheduling and fault injection for filesystem using FUSE:

$ mkdir /tmp/{nmzfs-orig,nmzfs}
$ sudo nmz inspectors fs -original-dir /tmp/nmzfs-orig -mount-point /tmp/nmzfs -autopilot config.toml
$ sudo fusermount -u /tmp/nmzfs

Using filesystem inspector, we successfully found YARN-4301.

Container CLI

We introduced Namazu Container, a new human-friendly, Docker-like CLI:

$ sudo nmz container run -it --rm -v /foo:/foo ubuntu bash

In Namazu Container, you can run arbitrary command that might be flaky. JUnit tests are interesting to try.

nmzc$ git clone something
nmzc$ cd something
nmzc$ for f in $(seq 1 1000);do mvn test; done

By default, only process inspector is enabled in Namazu Container. Please refer to README file for configuration.

Semi-deterministic replaying API

Semi-deterministic replayer is an experimental feature: it determines a delay for an event using a seed value and the hash of the event, rather than just using a random value.

It does not guarantee full determinism, but we believe it is sometimes enough for debugging.

Miscellaneous improvements

  • Renamed Earthquake to Namazu, and introduced a logo image
  • Support static build
  • Unit tests for Namazu itself


Recently, we made presentations at two events: CoreOS Fest (May 10) and ApacheCon Core NA (May 12).

Please refer to the article in our blog.