github.com/ferranbt/nomad@v0.9.3-0.20190607002617-85c449b7667c/website/source/docs/enterprise/preemption/index.html.md (about)

     1  ---
     2  layout: "docs"
     3  page_title: "Nomad Enterprise Preemption"
     4  sidebar_current: "docs-enterprise-preemption"
     5  description: |-
     6    Nomad Enterprise preemption capabilities enable the scheduler to temporarily
     7    evict lower priority allocations for service and batch jobs so that
     8    higher priority allocations can be placed. 
     9  ---
    10  
    11  # Nomad Enterprise Preemption
    12  
    13  When a Nomad cluster is at capacity for a given set of placement constraints, any allocations 
    14  that result from a newly scheduled service or batch job will remain in the pending state until 
    15  sufficient resources become available - regardless of the defined priority.
    16  
    17  [Preemption](/docs/internals/scheduling/preemption.html) capabilities in 
    18  [Nomad Enterprise](https://www.hashicorp.com/go/nomad-enterprise) enable the scheduler to temporarily 
    19  evict lower [priority](/docs/job-specification/job.html#priority) allocations from service and 
    20  batch jobs so that the allocations from higher priority jobs can be placed. This behavior 
    21  ensures that critical workloads can run when resources are limited or when partial outages require 
    22  workloads to be rescheduled across a smaller set of client nodes.
    23  
    24  See the [Preemption internals documentation](/docs/internals/scheduling/preemption.html) for a 
    25  more detailed overview. Preemption for service and batch jobs can be enabled using the [scheduler config API endpoint](/api/operator.html#update-scheduler-configuration).
    26  
    27  Click [here](https://www.hashicorp.com/go/nomad-enterprise) to set up a demo or 
    28  request a trial of Nomad Enterprise.