Jepsen is a tool, written by Kyle Kingsbury, designed to test the partition tolerance of distributed systems. It creates network partitions while fuzzing the system with random operations. The results are analyzed to see if the system violates any of the consistency properties it claims to have.
As part of our Consul testing, we ran a Jepsen test to determine if any consistency issues could be uncovered. In our testing, Consul gracefully recovered from partitions without introducing any consistency issues.
At the moment, testing with Jepsen is rather complex as it requires setting up multiple virtual machines, SSH keys, DNS configuration, and a working Clojure environment. We hope to contribute our Consul testing code upstream and to provide a Vagrant environment for Jepsen testing soon.
Below is the output captured from Jepsen. We ran Jepsen multiple times, and it passed each time. This output is only representative of a single run and has been edited for length. Please reach out on Consul's Discuss if you would like to reproduce the Jepsen results.
$ lein test :only jepsen.system.consul-test
lein test jepsen.system.consul-test
INFO jepsen.os.debian - :n5 setting up debian
INFO jepsen.os.debian - :n3 setting up debian
INFO jepsen.os.debian - :n4 setting up debian
INFO jepsen.os.debian - :n1 setting up debian
INFO jepsen.os.debian - :n2 setting up debian
INFO jepsen.os.debian - :n4 debian set up
INFO jepsen.os.debian - :n5 debian set up
INFO jepsen.os.debian - :n3 debian set up
INFO jepsen.os.debian - :n1 debian set up
INFO jepsen.os.debian - :n2 debian set up
INFO jepsen.system.consul - :n1 consul nuked
INFO jepsen.system.consul - :n4 consul nuked
INFO jepsen.system.consul - :n5 consul nuked
INFO jepsen.system.consul - :n3 consul nuked
INFO jepsen.system.consul - :n2 consul nuked
INFO jepsen.system.consul - Running nodes: {:n1 false, :n2 false, :n3 false, :n4 false, :n5 false}
INFO jepsen.system.consul - :n2 consul nuked
INFO jepsen.system.consul - :n3 consul nuked
INFO jepsen.system.consul - :n4 consul nuked
INFO jepsen.system.consul - :n5 consul nuked
INFO jepsen.system.consul - :n1 consul nuked
INFO jepsen.system.consul - :n1 starting consul
INFO jepsen.system.consul - :n2 starting consul
INFO jepsen.system.consul - :n4 starting consul
INFO jepsen.system.consul - :n5 starting consul
INFO jepsen.system.consul - :n3 starting consul
INFO jepsen.system.consul - :n3 consul ready
INFO jepsen.system.consul - :n2 consul ready
INFO jepsen.system.consul - Running nodes: {:n1 true, :n2 true, :n3 true, :n4 true, :n5 true}
INFO jepsen.system.consul - :n5 consul ready
INFO jepsen.system.consul - :n1 consul ready
INFO jepsen.system.consul - :n4 consul ready
INFO jepsen.core - Worker 0 starting
INFO jepsen.core - Worker 2 starting
INFO jepsen.core - Worker 1 starting
INFO jepsen.core - Worker 3 starting
INFO jepsen.core - Worker 4 starting
INFO jepsen.util - 2 :invoke :read nil
INFO jepsen.util - 3 :invoke :cas [4 4]
INFO jepsen.util - 0 :invoke :write 4
INFO jepsen.util - 1 :invoke :write 1
INFO jepsen.util - 4 :invoke :cas [4 0]
INFO jepsen.util - 2 :ok :read nil
INFO jepsen.util - 4 :fail :cas [4 0]
(Log Truncated...)
INFO jepsen.util - 4 :invoke :cas [3 3]
INFO jepsen.util - 4 :fail :cas [3 3]
INFO jepsen.util - :nemesis :info :stop nil
INFO jepsen.util - :nemesis :info :stop "fully connected"
INFO jepsen.util - 0 :fail :read nil
INFO jepsen.util - 1 :fail :write 0
INFO jepsen.util - :nemesis :info :stop nil
INFO jepsen.util - :nemesis :info :stop "fully connected"
INFO jepsen.core - nemesis done
INFO jepsen.core - Worker 3 done
INFO jepsen.util - 1 :invoke :read nil
INFO jepsen.core - Worker 2 done
INFO jepsen.core - Worker 4 done
INFO jepsen.core - Worker 0 done
INFO jepsen.util - 1 :ok :read 3
INFO jepsen.core - Worker 1 done
INFO jepsen.core - Run complete, writing
INFO jepsen.core - Analyzing
(Log Truncated...)
INFO jepsen.core - Analysis complete
INFO jepsen.system.consul - :n3 consul nuked
INFO jepsen.system.consul - :n2 consul nuked
INFO jepsen.system.consul - :n4 consul nuked
INFO jepsen.system.consul - :n1 consul nuked
INFO jepsen.system.consul - :n5 consul nuked
1964 element history linearizable. :D
Ran 1 tests containing 1 assertions.
0 failures, 0 errors.
