Yuliya Feldman commented on YARN-796:

Thank you for your comments

The NM can still periodically refreshes its own labels, and update the RM via 
the heartbeat mechanism. The RM should also expose a "node label report", which 
is the real-time information of all nodes and their labels.
Yes - you would have yarn command to "showlabels" that would show  all the 
labels in the cluster
"yarn rmadmin -showlabels"

2. Labels are per-container, not per-app. Right? The doc keeps mentioning 
"application label", "ApplicationLabelExpression", etc. Should those be 
"container label" instead? I just want to confirm that each container request 
can carry its own label expression. Example use case: Only the mappers need 
GPU, not the reducers.

Proposal here to have labels per application, not per containers. Though it is 
not that hard to specify label per container (rather per Request) 
There are pros and cons for both (per container and per app):
pros for App - the only place to "setLabel" is ApplicationSubmissionContext
cons for App - as you said - you want one configuration for Mappers and other 
for Reducers
cons for container level labels - every application that wants to take 
advantage of the labels will have to code it in their AppMaster while creating 

--- The proposal uses regexes on FQDN, such as perfnode.*. 

File with labels does not need to contain Regexes for FQDN - since it will be 
based solely on what "hostname" what is used in "isBlackListed()" method.
But I surely open to suggestions to get labels from nodes, as long as it is not 
high burden on the Cluster Admin who needs to specify labels per node on the 

--- Can we fail container requests with no satisfying nodes?

I think it would be the same behavior as for any other Request that can not be 
satisfied because queues were setup incorrectly, or there is no free resource 
available t the moment. How would you differentiate between those cases?

> Allow for (admin) labels on nodes and resource-requests
> -------------------------------------------------------
>                 Key: YARN-796
>                 URL: https://issues.apache.org/jira/browse/YARN-796
>             Project: Hadoop YARN
>          Issue Type: Sub-task
>            Reporter: Arun C Murthy
>            Assignee: Wangda Tan
>         Attachments: LabelBasedScheduling.pdf, YARN-796.patch
> It will be useful for admins to specify labels for nodes. Examples of labels 
> are OS, processor architecture etc.
> We should expose these labels and allow applications to specify labels on 
> resource-requests.
> Obviously we need to support admin operations on adding/removing node labels.

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