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by OJFord
1957 days ago
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> - Job: Job is a collection of different groups. Job is where the constraints for type of scheduler, update strategies and ACL is placed. > - Group: Group is a collection of different tasks. A group is always executed on the same Nomad client node. You'll want to use Groups for use-cases like a logging sidecar, reverse proxies etc. > - Task: Atomic unit of work. A task in Nomad can be running a container/binary/Java VM etc, defining the mount points, env variables, ports to be exposed etc. > If you're coming from K8s you can think of Task as a Pod and Group as a Replicaset. There's no equivalent to Job in K8s. Is that right? I haven't used Nomad (yet?) but, as described, it sounds to me more like Job ~= Deployment; Group ~= Pod; Task ~= Container? |
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A Task is an individual unit of work: a container, executable, JVM app, etc.
A Task Group/Allocation is a group of Tasks that will be placed together on nodes as a unit.
A Job is a collection of Task Groups and is where you tell Nomad how to schedule the work. A "system" Job is scheduled across all Nodes somewhat like a DaemonSet. A "batch" Job can be submitted as a one-off execution, periodic (run on a schedule) or parameterized (run on demand with variables specified at runtime). A "service" Job is the "normal" scheduler where all Task Groups are treated like ReplicaSets.
Placement is determined by constraints that can be specified on each Task Group.