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# distributed with this work for additional information
# regarding copyright ownership. The ASF licenses this file
# to you under the Apache License, Version 2.0 (the
# "License"); you may not use this file except in compliance
# with the License. You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing,
# software distributed under the License is distributed on an
# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
# KIND, either express or implied. See the License for the
# specific language governing permissions and limitations
# under the License.
from __future__ import annotations
import contextlib
import json
import multiprocessing
import time
from queue import Empty, Queue
from typing import TYPE_CHECKING, Any, Generic, TypeVar
from kubernetes import client, watch
from kubernetes.client.rest import ApiException
from urllib3.exceptions import ReadTimeoutError
from airflow.exceptions import AirflowException
from airflow.providers.cncf.kubernetes.kube_client import get_kube_client
from airflow.providers.cncf.kubernetes.kubernetes_helper_functions import (
annotations_for_logging_task_metadata,
annotations_to_key,
create_pod_id,
)
from airflow.providers.cncf.kubernetes.pod_generator import PodGenerator
from airflow.utils.log.logging_mixin import LoggingMixin
from airflow.utils.state import TaskInstanceState
try:
from airflow.providers.cncf.kubernetes.executors.kubernetes_executor_types import (
ADOPTED,
ALL_NAMESPACES,
POD_EXECUTOR_DONE_KEY,
)
except ImportError:
# avoid failing import when Airflow pre 2.7 is installed
from airflow.kubernetes.kubernetes_executor_types import ( # type: ignore[no-redef]
ALL_NAMESPACES,
POD_EXECUTOR_DONE_KEY,
)
if TYPE_CHECKING:
from kubernetes.client import Configuration, models as k8s
from airflow.providers.cncf.kubernetes.executors.kubernetes_executor_types import (
KubernetesJobType,
KubernetesResultsType,
KubernetesWatchType,
)
# Singleton here is duplicated version of airflow.utils.singleton.Singleton until
# min-airflow version is 2.7.0 for the provider. then it can be imported from airflow.utils.singleton.
[docs]class Singleton(type, Generic[T]):
"""Metaclass that allows to implement singleton pattern."""
_instances: dict[Singleton[T], T] = {}
[docs] def __call__(cls: Singleton[T], *args, **kwargs) -> T:
if cls not in cls._instances:
cls._instances[cls] = super().__call__(*args, **kwargs)
return cls._instances[cls]
[docs]class ResourceVersion(metaclass=Singleton):
"""Singleton for tracking resourceVersion from Kubernetes."""
[docs] resource_version: dict[str, str] = {}
[docs]class KubernetesJobWatcher(multiprocessing.Process, LoggingMixin):
"""Watches for Kubernetes jobs."""
def __init__(
self,
namespace: str,
watcher_queue: Queue[KubernetesWatchType],
resource_version: str | None,
scheduler_job_id: str,
kube_config: Configuration,
):
super().__init__()
self.namespace = namespace
self.scheduler_job_id = scheduler_job_id
self.watcher_queue = watcher_queue
self.resource_version = resource_version
self.kube_config = kube_config
[docs] def run(self) -> None:
"""Perform watching."""
if TYPE_CHECKING:
assert self.scheduler_job_id
kube_client: client.CoreV1Api = get_kube_client()
while True:
try:
self.resource_version = self._run(
kube_client, self.resource_version, self.scheduler_job_id, self.kube_config
)
except ReadTimeoutError:
self.log.warning(
"There was a timeout error accessing the Kube API. Retrying request.", exc_info=True
)
time.sleep(1)
except Exception:
self.log.exception("Unknown error in KubernetesJobWatcher. Failing")
self.resource_version = "0"
ResourceVersion().resource_version[self.namespace] = "0"
raise
else:
self.log.warning(
"Watch died gracefully, starting back up with: last resource_version: %s",
self.resource_version,
)
def _pod_events(self, kube_client: client.CoreV1Api, query_kwargs: dict):
watcher = watch.Watch()
try:
if self.namespace == ALL_NAMESPACES:
return watcher.stream(kube_client.list_pod_for_all_namespaces, **query_kwargs)
else:
return watcher.stream(kube_client.list_namespaced_pod, self.namespace, **query_kwargs)
except ApiException as e:
if str(e.status) == "410": # Resource version is too old
if self.namespace == ALL_NAMESPACES:
pods = kube_client.list_pod_for_all_namespaces(watch=False)
else:
pods = kube_client.list_namespaced_pod(namespace=self.namespace, watch=False)
resource_version = pods.metadata.resource_version
query_kwargs["resource_version"] = resource_version
return self._pod_events(kube_client=kube_client, query_kwargs=query_kwargs)
else:
raise
def _run(
self,
kube_client: client.CoreV1Api,
resource_version: str | None,
scheduler_job_id: str,
kube_config: Any,
) -> str | None:
self.log.info("Event: and now my watch begins starting at resource_version: %s", resource_version)
kwargs = {"label_selector": f"airflow-worker={scheduler_job_id}"}
if resource_version:
kwargs["resource_version"] = resource_version
if kube_config.kube_client_request_args:
for key, value in kube_config.kube_client_request_args.items():
kwargs[key] = value
last_resource_version: str | None = None
for event in self._pod_events(kube_client=kube_client, query_kwargs=kwargs):
task = event["object"]
self.log.debug("Event: %s had an event of type %s", task.metadata.name, event["type"])
if event["type"] == "ERROR":
return self.process_error(event)
annotations = task.metadata.annotations
task_instance_related_annotations = {
"dag_id": annotations["dag_id"],
"task_id": annotations["task_id"],
"execution_date": annotations.get("execution_date"),
"run_id": annotations.get("run_id"),
"try_number": annotations["try_number"],
}
map_index = annotations.get("map_index")
if map_index is not None:
task_instance_related_annotations["map_index"] = map_index
self.process_status(
pod_name=task.metadata.name,
namespace=task.metadata.namespace,
status=task.status.phase,
annotations=task_instance_related_annotations,
resource_version=task.metadata.resource_version,
event=event,
)
last_resource_version = task.metadata.resource_version
return last_resource_version
[docs] def process_error(self, event: Any) -> str:
"""Process error response."""
self.log.error("Encountered Error response from k8s list namespaced pod stream => %s", event)
raw_object = event["raw_object"]
if raw_object["code"] == 410:
self.log.info(
"Kubernetes resource version is too old, must reset to 0 => %s", (raw_object["message"],)
)
# Return resource version 0
return "0"
raise AirflowException(
f"Kubernetes failure for {raw_object['reason']} with code {raw_object['code']} and message: "
f"{raw_object['message']}"
)
[docs] def process_status(
self,
pod_name: str,
namespace: str,
status: str,
annotations: dict[str, str],
resource_version: str,
event: Any,
) -> None:
pod = event["object"]
annotations_string = annotations_for_logging_task_metadata(annotations)
"""Process status response."""
if event["type"] == "DELETED" and not pod.metadata.deletion_timestamp:
# This will happen only when the task pods are adopted by another executor.
# So, there is no change in the pod state.
# However, need to free the executor slot from the current executor.
self.log.info("Event: pod %s adopted, annotations: %s", pod_name, annotations_string)
self.watcher_queue.put((pod_name, namespace, ADOPTED, annotations, resource_version))
elif status == "Pending":
# deletion_timestamp is set by kube server when a graceful deletion is requested.
# since kube server have received request to delete pod set TI state failed
if event["type"] == "DELETED" and pod.metadata.deletion_timestamp:
self.log.info("Event: Failed to start pod %s, annotations: %s", pod_name, annotations_string)
self.watcher_queue.put(
(pod_name, namespace, TaskInstanceState.FAILED, annotations, resource_version)
)
elif (
self.kube_config.worker_pod_pending_fatal_container_state_reasons
and "status" in event["raw_object"]
):
self.log.info("Event: %s Pending, annotations: %s", pod_name, annotations_string)
# Init containers and base container statuses to check.
# Skipping the other containers statuses check.
container_statuses_to_check = []
if "initContainerStatuses" in event["raw_object"]["status"]:
container_statuses_to_check.extend(event["raw_object"]["status"]["initContainerStatuses"])
if "containerStatuses" in event["raw_object"]["status"]:
container_statuses_to_check.append(event["raw_object"]["status"]["containerStatuses"][0])
for container_status in container_statuses_to_check:
container_status_state = container_status["state"]
if "waiting" in container_status_state:
if (
container_status_state["waiting"]["reason"]
in self.kube_config.worker_pod_pending_fatal_container_state_reasons
):
if (
container_status_state["waiting"]["reason"] == "ErrImagePull"
and container_status_state["waiting"]["message"] == "pull QPS exceeded"
):
continue
self.watcher_queue.put(
(pod_name, namespace, TaskInstanceState.FAILED, annotations, resource_version)
)
break
else:
self.log.debug("Event: %s Pending, annotations: %s", pod_name, annotations_string)
elif status == "Failed":
self.log.error("Event: %s Failed, annotations: %s", pod_name, annotations_string)
self.watcher_queue.put(
(pod_name, namespace, TaskInstanceState.FAILED, annotations, resource_version)
)
elif status == "Succeeded":
# We get multiple events once the pod hits a terminal state, and we only want to
# send it along to the scheduler once.
# If our event type is DELETED, we have the POD_EXECUTOR_DONE_KEY, or the pod has
# a deletion timestamp, we've already seen the initial Succeeded event and sent it
# along to the scheduler.
if (
event["type"] == "DELETED"
or POD_EXECUTOR_DONE_KEY in pod.metadata.labels
or pod.metadata.deletion_timestamp
):
self.log.info(
"Skipping event for Succeeded pod %s - event for this pod already sent to executor",
pod_name,
)
return
self.log.info("Event: %s Succeeded, annotations: %s", pod_name, annotations_string)
self.watcher_queue.put((pod_name, namespace, None, annotations, resource_version))
elif status == "Running":
# deletion_timestamp is set by kube server when a graceful deletion is requested.
# since kube server have received request to delete pod set TI state failed
if event["type"] == "DELETED" and pod.metadata.deletion_timestamp:
self.log.info(
"Event: Pod %s deleted before it could complete, annotations: %s",
pod_name,
annotations_string,
)
self.watcher_queue.put(
(pod_name, namespace, TaskInstanceState.FAILED, annotations, resource_version)
)
else:
self.log.info("Event: %s is Running, annotations: %s", pod_name, annotations_string)
else:
self.log.warning(
"Event: Invalid state: %s on pod: %s in namespace %s with annotations: %s with "
"resource_version: %s",
status,
pod_name,
namespace,
annotations,
resource_version,
)
[docs]class AirflowKubernetesScheduler(LoggingMixin):
"""Airflow Scheduler for Kubernetes."""
def __init__(
self,
kube_config: Any,
result_queue: Queue[KubernetesResultsType],
kube_client: client.CoreV1Api,
scheduler_job_id: str,
):
super().__init__()
self.log.debug("Creating Kubernetes executor")
self.kube_config = kube_config
self.result_queue = result_queue
self.namespace = self.kube_config.kube_namespace
self.log.debug("Kubernetes using namespace %s", self.namespace)
self.kube_client = kube_client
self._manager = multiprocessing.Manager()
self.watcher_queue = self._manager.Queue()
self.scheduler_job_id = scheduler_job_id
self.kube_watchers = self._make_kube_watchers()
[docs] def run_pod_async(self, pod: k8s.V1Pod, **kwargs):
"""Run POD asynchronously."""
sanitized_pod = self.kube_client.api_client.sanitize_for_serialization(pod)
json_pod = json.dumps(sanitized_pod, indent=2)
self.log.debug("Pod Creation Request: \n%s", json_pod)
try:
resp = self.kube_client.create_namespaced_pod(
body=sanitized_pod, namespace=pod.metadata.namespace, **kwargs
)
self.log.debug("Pod Creation Response: %s", resp)
except Exception as e:
self.log.exception("Exception when attempting to create Namespaced Pod: %s", json_pod)
raise e
return resp
def _make_kube_watcher(self, namespace) -> KubernetesJobWatcher:
resource_version = ResourceVersion().resource_version.get(namespace, "0")
watcher = KubernetesJobWatcher(
watcher_queue=self.watcher_queue,
namespace=namespace,
resource_version=resource_version,
scheduler_job_id=self.scheduler_job_id,
kube_config=self.kube_config,
)
watcher.start()
return watcher
def _make_kube_watchers(self) -> dict[str, KubernetesJobWatcher]:
watchers = {}
if self.kube_config.multi_namespace_mode:
namespaces_to_watch = (
self.kube_config.multi_namespace_mode_namespace_list
if self.kube_config.multi_namespace_mode_namespace_list
else [ALL_NAMESPACES]
)
else:
namespaces_to_watch = [self.kube_config.kube_namespace]
for namespace in namespaces_to_watch:
watchers[namespace] = self._make_kube_watcher(namespace)
return watchers
def _health_check_kube_watchers(self):
for namespace, kube_watcher in self.kube_watchers.items():
if kube_watcher.is_alive():
self.log.debug("KubeJobWatcher for namespace %s alive, continuing", namespace)
else:
self.log.error(
(
"Error while health checking kube watcher process for namespace %s. "
"Process died for unknown reasons"
),
namespace,
)
ResourceVersion().resource_version[namespace] = "0"
self.kube_watchers[namespace] = self._make_kube_watcher(namespace)
[docs] def run_next(self, next_job: KubernetesJobType) -> None:
"""Receives the next job to run, builds the pod, and creates it."""
key, command, kube_executor_config, pod_template_file = next_job
dag_id, task_id, run_id, try_number, map_index = key
if command[0:3] != ["airflow", "tasks", "run"]:
raise ValueError('The command must start with ["airflow", "tasks", "run"].')
base_worker_pod = get_base_pod_from_template(pod_template_file, self.kube_config)
if not base_worker_pod:
raise AirflowException(
f"could not find a valid worker template yaml at {self.kube_config.pod_template_file}"
)
pod = PodGenerator.construct_pod(
namespace=self.namespace,
scheduler_job_id=self.scheduler_job_id,
pod_id=create_pod_id(dag_id, task_id),
dag_id=dag_id,
task_id=task_id,
kube_image=self.kube_config.kube_image,
try_number=try_number,
map_index=map_index,
date=None,
run_id=run_id,
args=command,
pod_override_object=kube_executor_config,
base_worker_pod=base_worker_pod,
with_mutation_hook=True,
)
# Reconcile the pod generated by the Operator and the Pod
# generated by the .cfg file
self.log.info(
"Creating kubernetes pod for job is %s, with pod name %s, annotations: %s",
key,
pod.metadata.name,
annotations_for_logging_task_metadata(pod.metadata.annotations),
)
self.log.debug("Kubernetes running for command %s", command)
self.log.debug("Kubernetes launching image %s", pod.spec.containers[0].image)
# the watcher will monitor pods, so we do not block.
self.run_pod_async(pod, **self.kube_config.kube_client_request_args)
self.log.debug("Kubernetes Job created!")
[docs] def delete_pod(self, pod_name: str, namespace: str) -> None:
"""Delete Pod from a namespace; does not raise if it does not exist."""
try:
self.log.debug("Deleting pod %s in namespace %s", pod_name, namespace)
self.kube_client.delete_namespaced_pod(
pod_name,
namespace,
body=client.V1DeleteOptions(**self.kube_config.delete_option_kwargs),
**self.kube_config.kube_client_request_args,
)
except ApiException as e:
# If the pod is already deleted
if str(e.status) != "404":
raise
[docs] def patch_pod_executor_done(self, *, pod_name: str, namespace: str):
"""Add a "done" annotation to ensure we don't continually adopt pods."""
self.log.debug("Patching pod %s in namespace %s to mark it as done", pod_name, namespace)
try:
self.kube_client.patch_namespaced_pod(
name=pod_name,
namespace=namespace,
body={"metadata": {"labels": {POD_EXECUTOR_DONE_KEY: "True"}}},
)
except ApiException as e:
self.log.info("Failed to patch pod %s with done annotation. Reason: %s", pod_name, e)
[docs] def sync(self) -> None:
"""
Check the status of all currently running kubernetes jobs.
If a job is completed, its status is placed in the result queue to be sent back to the scheduler.
"""
self.log.debug("Syncing KubernetesExecutor")
self._health_check_kube_watchers()
with contextlib.suppress(Empty):
while True:
task = self.watcher_queue.get_nowait()
try:
self.log.debug("Processing task %s", task)
self.process_watcher_task(task)
finally:
self.watcher_queue.task_done()
[docs] def process_watcher_task(self, task: KubernetesWatchType) -> None:
"""Process the task by watcher."""
pod_name, namespace, state, annotations, resource_version = task
self.log.debug(
"Attempting to finish pod; pod_name: %s; state: %s; annotations: %s",
pod_name,
state,
annotations_for_logging_task_metadata(annotations),
)
key = annotations_to_key(annotations=annotations)
if key:
self.log.debug("finishing job %s - %s (%s)", key, state, pod_name)
self.result_queue.put((key, state, pod_name, namespace, resource_version))
def _flush_watcher_queue(self) -> None:
self.log.debug("Executor shutting down, watcher_queue approx. size=%d", self.watcher_queue.qsize())
with contextlib.suppress(Empty):
while True:
task = self.watcher_queue.get_nowait()
# Ignoring it since it can only have either FAILED or SUCCEEDED pods
self.log.warning("Executor shutting down, IGNORING watcher task=%s", task)
self.watcher_queue.task_done()
[docs] def terminate(self) -> None:
"""Terminates the watcher."""
self.log.debug("Terminating kube_watchers...")
for kube_watcher in self.kube_watchers.values():
kube_watcher.terminate()
kube_watcher.join()
self.log.debug("kube_watcher=%s", kube_watcher)
self.log.debug("Flushing watcher_queue...")
self._flush_watcher_queue()
# Queue should be empty...
self.watcher_queue.join()
self.log.debug("Shutting down manager...")
self._manager.shutdown()
[docs]def get_base_pod_from_template(pod_template_file: str | None, kube_config: Any) -> k8s.V1Pod:
"""
Get base pod from template.
Reads either the pod_template_file set in the executor_config or the base pod_template_file
set in the airflow.cfg to craft a "base pod" that will be used by the KubernetesExecutor
:param pod_template_file: absolute path to a pod_template_file.yaml or None
:param kube_config: The KubeConfig class generated by airflow that contains all kube metadata
:return: a V1Pod that can be used as the base pod for k8s tasks
"""
if pod_template_file:
return PodGenerator.deserialize_model_file(pod_template_file)
else:
return PodGenerator.deserialize_model_file(kube_config.pod_template_file)
