Merge pull request #4425 from hashicorp/d-warn-impossible-constraint

Added warning about impossible constraints
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Charlie Voiselle 2018-06-19 12:06:22 -04:00 committed by GitHub
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@ -28,6 +28,11 @@ filter on [attributes][interpolation] or [client metadata][client-meta].
Additionally constraints may be specified at the [job][job], [group][group], or
[task][task] levels for ultimate flexibility.
~> **It is possible to define irreconcilable constraints in a job.**
For example, because all [tasks within a group are scheduled on the same client node][group],
specifying different [`${attr.unique.hostname}`][node-variables] constraints at
the task level will cause a job to be unplaceable.
```hcl
job "docs" {
# All tasks in this job must run on linux.
@ -273,3 +278,4 @@ constraint {
[client-meta]: /docs/agent/configuration/client.html#meta "Nomad meta Job Specification"
[task]: /docs/job-specification/task.html "Nomad task Job Specification"
[interpolation]: /docs/runtime/interpolation.html "Nomad interpolation"
[node-variables]: /docs/runtime/interpolation.html#node-variables- "Nomad interpolation-Node variables"