Apache Chronos Architecture Explaination

Question

I was trying to see what makes Chronos better than Crons? I am not able to understand its job scheduling and executing architecture completely.

Specifically, these are

Answer 1

Some of your questions are answered in my reply here so I will focus on the other questions not addressed.

2. Chronos stores state in memory unless you are using Zookeeper, in which case it is stored in Zookeeper at /chronos/state by default reference here.

3. See: Chronos: How does it work?

4. Based on lastsuccess and lastfailure seen here

5. Because the authors decided to use JSON and a RESTful API

6. Yes. The use of && or bash scripts... They will all be executed on the same machine that the job is running on. No, single jobs cannot run the commands in parallel, but multiple jobs could be scheduled at the same time.

7. Because Chronos is for short-lived cron jobs that can be scheduled on a regular basis, whereas Marathon is for long-lived tasks. The reason Chronos is a good replacement for cron is that it is wholly dependent on Mesos - which means you can also use Mesos attributes to schedule jobs around your Mesos cluster appropriately. See here and here

8. Nope.

9. The state of async jobs is suspect, it looks like it was removed but still unfortunately has some references in the documentation.