import json import uuid from pathlib import Path from time import sleep import pykube import yaml from munch import Munch api = pykube.HTTPClient(pykube.KubeConfig.from_env()) def volume_to_node(volume_id): pv = pykube.PersistentVolume.objects(api).get_by_name(name=volume_id) pv = Munch.fromDict(pv.obj) node_name = pv.spec.nodeAffinity.required.nodeSelectorTerms[0].matchExpressions[0][ "values" ][0] expected_node_affainity = yaml.safe_load( f""" required: nodeSelectorTerms: - matchExpressions: - key: hostname operator: In values: - {node_name} """ ) assert pv.spec.nodeAffinity == expected_node_affainity return node_name def wait_for(pred, desc=""): print(f"Waiting for {desc}", end="", flush=True) while not pred(): print(".", end="", flush=True) sleep(0.5) print(" done") def run_on_node(fn, node): name = f"task-{uuid.uuid4()}" ctx = { "name": name, "namespace": "kube-system", # FIXME "nodeSelector": json.dumps({"kubernetes.io/hostname": node}), "cmd": json.dumps(fn), } template = Path("./templates/task.yaml").read_bytes().decode() manifest = template.format(**ctx) obj = yaml.safe_load(manifest) task_pod = pykube.Pod(api, obj) task_pod.create() def is_finished(): task_pod.reload() status = task_pod.obj["status"] if status["phase"] in ["Succeeded", "Failed"]: return True return False wait_for(is_finished, "task to finish") if task_pod.obj["status"]["phase"] != "Succeeded": raise Exception(f"Task {name} failed") task_pod.delete()