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mesos
Support for constraints in chronos
Is it possible to add support to chronos for constraints, such as those that marathon already supports (https://mesosphere.github.io/marathon/docs/constraints.html)?
For example, it would be very useful to be able to schedule jobs to be run in a particular data center.
Also, is there an existing workaround for this?
Adding constraints would be an important feature for Chronos. Patches from the community would be excellent if we aren't able to add this in our immediate roadmap.
Having marathon-like constrains feature would be super cool - https://mesosphere.github.io/marathon/docs/constraints.html
+1 ... having the ability to specify parts of your cluster to run jobs on would great...
Hey gents, instead of a pointless +1, just click the Subscribe button on the top right. More and more +1s are not very useful and just spam the developers unnecessarily.
@SEJeff, the +1s can be helpful for prioritisation. Ideally we'd have a less spammy system or the ability to vote built into GH issues, of course.
That is what subscribe is for :)
I comaintain a few largish open source projects (> 500 unique contributors each), salt and graphite. It works pretty well.
@brndnmtthws How hard would this be to accomplish, do you have any idea. It is most certainly an important feature.
This works pretty well now for us in latest version. Thanks. Curious why this issue is still open now?
Isn't it still restricted to just the EQUALS constraint at this point? I think the intent is to bring it to parity with Marathon wrt constraints.
Oh yes, agreed.EQUALS was serving our purpose, didn't realize the full story. Thanks.
Not yet. On Sep 4, 2015 1:27 PM, "tony kerz" [email protected] wrote:
is there any support for running a job on every slave in a cluster?
— Reply to this email directly or view it on GitHub https://github.com/mesos/chronos/issues/256#issuecomment-137711020.
is something like below supposed to work?:
"constraints": [
["hostname", "EQUALS", "ip-10-0-0-95.ec2.internal"]
],
Yes. EQUALS is one of the supported constraints per the docs: https://mesos.github.io/chronos/docs/api.html#constraints
thx @solarkennedy, i saw that, but it wasn't clear to me if hostname was an attribute that was auto-magically made available to chronos for use with EQUAL/LIKE constraints or if those would only work on attributes that i manually punched into a slave via something like --attributes (which i found somewhere in the mesos doc), or MESOS_ATTRIBUTES (which i see in the cloud-formation file provided by mesosphere).
looks like marathon is pretty good about setting up hostname for use with constraints, but i saw no such info in the chronos doc.
That is true, the docs do assume that the attribute used by the constraint is declared. As far as I know hostname is not a magic attribute that you get for free.
Can you make a PR to clarify that and cross-link to the mesos docs on how to add attributes? If not I could do it.
@solarkennedy i can take a whack at clarifying the docs.
more importantly tho, i think it would be great if hostname was made available by default for constraints as it is in marathon. do you think this would be a valuable feature? if so, do you think it is (or should be) implied by this particular issue, or do you think it should be spiked out as a sep enhancement request?
I'm not sure. I was not aware that that was a "free" constraint that you could use from marathon, even if you didn't set that as a mesos attribute. (I assumed the constraint language only operated on mesos attributes)
check the last sentence of the first paragraph at this link: https://mesosphere.github.io/marathon/docs/constraints.html
The field can be the slave hostname or any Mesos slave attribute.
i've constrained to hostname successfully in marathon as well without doing anything special.
Ah! Today I learned. @tony-kerz for this specific feature I recommend making a separate issue/pr.
If you ask me this main issue should be closed, as there is some constraint functionality. Any new feature requests or doc updates and be new things.
Please support the hostname constraint in the future because I guess many people are using Marathon along with Chronos on top of Mesos. And Marathon already supported hostname constraint
