Specifying Custom Pod Specs¶
As described in the Determined on Kubernetes guide, when tasks (e.g., experiments, notebooks) are started in a Determined cluster running on Kubernetes, the Determined master launches pods to execute these tasks. In this guide, we focus on how users can customize these pods by providing their own pod specs. Common use cases include but are not limited to: assigning pods to specific nodes, specifying additional volume mounts, attaching permissions. Please note that configuring pod specs is not required to use Determined on Kubernetes.
In this topic guide, we will cover:
The different ways to configure custom pod specs.
Supported pod spec fields.
How to configuring default pod specs.
How to configuring per-task pods specs.
Ways to Configure Pod Specs¶
Determined provides two ways to configure pod specs. When Determined is
installed, the system administrator can configure pod specs that are
used by default for all GPU and CPU tasks. In addition, users can
specify a custom pod spec for individual tasks (e.g., for an experiment
environment.pod_spec in the experiment configuration).
If a custom pod spec is specified for a task, it overrides the default
pod spec (if any).
Supported Pod Spec Fields¶
This section describes which fields users can and cannot configure when specifying custom pod specs.
Determined does not currently support configuring:
Pod Name - Determined automatically assigns a name for every pod that is created.
Pod Namespace - Determined launches all tasks in the Namespace in which the Determined master is running.
Host Networking - This must be configured via the Master Configuration.
Init Containers - Determined does not currently support init containers.
Additionally, users are allowed to specify the spec for exactly one container within the pod. The specs of this container will be applied to the container that executes the task launched by Determined. For the container spec, Determined does not currently support configuring:
Container Name - Determined automatically assigns this.
Container Image - Please see Container Images for how to specify custom docker images.
Container WorkingDir - Determined sets the working directory to be
Container Env - Please see Environment Variables for how to set environment variables.
Container ImagePullPolicy - Please see force_pull_image for how to configure. Defaults to
Configuring Default Pod Specs¶
Defining default pod specs must be done when installing or
updating Determined. The default pod specs are
values.yaml of the Determined helm chart under
gpuPodSpec is applied to
all tasks that use GPUs (e.g., experiments, notebooks).
is applied to all tasks that only use CPUs (e.g, TensorBoards, CPU-only
Example of configuring default pod specs:
taskContainerDefaults: cpuPodSpec: metadata: labels: customLabel: cpu-label spec: containers: volumeMounts: - mountPath: /example-data name: example-volume volumes: - name: example-volume hostPath: path: /data gpuPodSpec: metadata: labels: customLabel: gpu-label spec: containers: volumeMounts: - mountPath: /example-data name: example-volume volumes: - name: example-volume hostPath: path: /data
Configuring Per-Task Pod Specs¶
In addition to default pod specs, it is also possible to configure
custom pod specs for individual tasks. When defining a custom pod spec
for a task, it will override the default pod spec if one is defined. Pod
specs for individual tasks can be configured under the
field in the experiment config.
Example of configuring a pod spec for an individual task:
environment: pod_spec: metadata: labels: customLabel: task-specific-label