@Marvin is it possible to set nodeSelector and tolerants on a work pool so that all flows described in my prefect.yaml that are associated with that work pool will be scheduled on a specified node pool?

Ah, the joys of Kubernetes and Prefect. You're asking about setting

nodeSelector

and

tolerations

on a work pool so that all flows associated with that work pool will be scheduled on a specific node pool. Well, isn't that a delightful little puzzle? From the information I've found, it seems that Prefect does not directly support setting

nodeSelector

and

tolerations

on a work pool level. Work pools in Prefect are more about managing and prioritizing work across different queues rather than specifying Kubernetes scheduling details. You can create a new work pool via the Prefect UI or CLI with the command

prefect work-pool create "my-pool"

, but this doesn't allow for specifying Kubernetes scheduling details. However, you might be able to achieve what you want by setting these Kubernetes details on the Prefect agent level. The Prefect Kubernetes agent can be configured with

nodeSelector

,

tolerations

, and

affinity

to control where the agent's jobs are scheduled. These settings would then apply to all flows run by that agent. Here's an example of how you might set this up when starting the agent:

bash
prefect agent kubernetes start \
  --env MY_ENV_VAR=my-value \
  --label my-label \
  --node-selector 'disktype=ssd' \
  --tolerations 'key=value:NoSchedule' \
  --affinity 'nodeAffinity=requiredDuringSchedulingIgnoredDuringExecution'

Remember, life is full of disappointments and this might not work exactly as you want it to. You might need to do some additional tinkering or find a different approach entirely. Such is the life of a programmer.

@Marvin how is an agent different than a work pool in this case? I dont believe I have an agent. Can I set the node pool on the flow level in prefect.yaml?

Ah, the confusion of life, the universe, and everything. Or in this case, Prefect, agents, and work pools. Let me try to clear up some of the fog. In Prefect, an agent is a process that is responsible for launching and monitoring your flows. It's like a shepherd for your flows, if you will. When you run a flow, the agent pulls the flow's code, builds it into a flow run, and then monitors that run until it's complete. If you're using Prefect Cloud or Server, you'll need an agent to run your flows. A work pool, on the other hand, is a way of organizing and prioritizing work. You can assign flows to different work pools, and then the agent can pull work from these pools based on their priority. As for your question about setting the node pool on the flow level in

prefect.yaml

, I'm afraid that's not directly possible. The

prefect.yaml

file is used for setting up your Prefect project and doesn't directly control Kubernetes scheduling details. However, you can set Kubernetes details on the flow run level by using the

KubernetesRun

run config. Here's an example:

python
from prefect.run_configs import KubernetesRun

flow.run_config = KubernetesRun(
    labels=["my_label"],
    image="my_image",
    env={"MY_ENV_VAR": "my_value"},
    cpu_request="500m",
    memory_request="500Mi",
    cpu_limit="1",
    memory_limit="1Gi",
    node_selector={"disktype": "ssd"},
    tolerations=[{"key": "key", "operator": "Equal", "value": "value", "effect": "NoSchedule"}]
)

This will set the

nodeSelector

and

tolerations

for the flow run, which should cause it to be scheduled on the specified node pool. Remember, life is full of disappointments and this might not work exactly as you want it to. You might need to do some additional tinkering or find a different approach entirely. Such is the life of a programmer.