2

Apologies for the noob question; I am new to using DC/OS (using v1.8.7) and have learnt that DC/OS has Marathon built in (Source: https://docs.mesosphere.com/1.8/administration/release-notes/).

When I go to the 'Universe' browser in DC/OS, I find that I can download and install the Marathon (v1.3.3) package.

  1. Is this package now redundant for the version of DC/OS that I am using?

  2. Why would I use the Marathon package in DC/OS - what features does it give to me that I don't already get from DC/OS?

I'm basically fumbling through setting up my first cluster and trying to learn as I go along, so I would appreciate any insight!

I have also posted the same question here: https://unix.stackexchange.com/questions/325103/what-benefits-does-the-marathon-package-bring-to-dc-os - but this forum doesn't seem to be any where near as active as StackOverflow; If i get an answer here, I will delete the other question or vice-versa.

Jay
  • 9,561
  • 7
  • 51
  • 72

1 Answers1

4

Great question, happy to provide some clarification since I think we don't do a great job explaining this.

Is this package now redundant for the version of DC/OS that I am using?

No. The use case for this package (called Marathon-on-Marathon or MoM for short) is to give users a user-land supervisor. You don't want to share the System Marathon with your users and allow everyone to install stuff from the Universe? OK, no problem, install a MoM for each of your users/teams/projects and they can do whatever they like within it (for example, install Jenkins, Spark, etc.)

Why would I use the Marathon package in DC/OS - what features does it give to me that I don't already get from DC/OS?

See above. No additional feature (there are even some limitations, that is, there's stuff you can do on the System Marathon you can't do in MoM) but think of it as a multi-tenant and/or security feature (well, a poor-man's, really—the Mesosphere DC/OS Enterprise Edition provides a full-featured environment like authn/authz, ACLs, secrets, etc.).

Michael Hausenblas
  • 13,162
  • 4
  • 52
  • 66
  • 1
    That has clarified a lot for me - great! One quick follow up question - I am using marathon-lb to load balance and expose some ports externally. This is installed from the universe on 'System marathon'. Is it possible to expose anything from a MoM service to the public world using the top-level instance of Marathon-lb, or do I need MoM level load balancers? I've tried adding the HAPROXY_GROUP label at the top level, and marathon-lb picks that up ok, but from within a MoM, it doesn't seem to pick it up. – Jay Nov 22 '16 at 10:11
  • 1
    Sure. When you install Marathon-LB you use `--options` with content like: `{ "marathon-lb": { "marathon-uri": "http://YOUR_MOM_URL" }}`, see also https://dcos.io/docs/1.8/usage/service-discovery/marathon-lb/usage/ for more details how to set it up – Michael Hausenblas Nov 22 '16 at 11:18