+
+h3(#preemptible). Using preemptible (spot) instances
+
+Preemptible instances typically offer lower cost computation with a tradeoff of lower service guarantees. If a compute node is preempted, Arvados will restart the computation on a new instance.
+
+If the sitewide configuration @Containers.AlwaysUsePreemptibleInstances@ is true, workflow steps will always select preemptible instances, regardless of user option.
+
+If @Containers.AlwaysUsePreemptibleInstances@ is false, you can request preemptible instances for a specific run with the @arvados-cwl-runner --enable-preemptible@ option.
+
+Within the workflow, you can control whether individual steps should be preemptible with the "arv:UsePreemptible":cwl-extensions.html#UsePreemptible hint.
+
+If a workflow requests preemptible instances with "arv:UsePreemptible":cwl-extensions.html#UsePreemptible , but you _do not_ want to use preemptible instances, you can override it for a specific run with the @arvados-cwl-runner --disable-preemptible@ option.
+
+h3(#gpu). Use CUDA GPU instances
+
+See "cwltool:CUDARequirement":cwl-extensions.html#CUDARequirement .