New Feature - Downscaling PodDisruptionBudgets (#43)

* added feature to downscale pod disruption budgets

* also added tests inside test_scaler.py

chart/templates/rbac.yaml

@@ -89,6 +89,16 @@ rules:
     - list
     - update
     - patch
+- apiGroups:
+    - policy
+  resources:
+    - poddisruptionbudgets
+  verbs:
+    - get
+    - watch
+    - list
+    - update
+    - patch
 ---
 apiVersion: rbac.authorization.k8s.io/v1
 kind: ClusterRoleBinding

kube_downscaler/cmd.py

@@ -10,6 +10,7 @@
         "horizontalpodautoscalers",
         "rollouts",
         "scaledobjects",
+        "poddisruptionbudgets"
     ]
 )
 

kube_downscaler/scaler.py

@@ -12,7 +12,7 @@
 from pykube import HorizontalPodAutoscaler
 from pykube import Namespace
 from pykube import StatefulSet
-from pykube.objects import NamespacedAPIObject
+from pykube.objects import NamespacedAPIObject, PodDisruptionBudget
 
 from kube_downscaler import helper
 from kube_downscaler.helper import matches_time_spec
@@ -39,6 +39,7 @@
     HorizontalPodAutoscaler,
     ArgoRollout,
     ScaledObject,
+    PodDisruptionBudget
 ]
 
 TIMESTAMP_FORMATS = [
@@ -166,6 +167,22 @@ def get_replicas(
         logger.debug(
             f"{resource.kind} {resource.namespace}/{resource.name} is {state} (original: {original_state}, uptime: {uptime})"
         )
+    elif resource.kind == "PodDisruptionBudget":
+        if "minAvailable" in resource.obj["spec"]:
+            replicas = resource.obj["spec"]["minAvailable"]
+            logger.debug(
+                f"{resource.kind} {resource.namespace}/{resource.name} has {replicas} minAvailable (original: {original_replicas}, uptime: {uptime})"
+            )
+        elif "maxUnavailable" in resource.obj["spec"]:
+            replicas = resource.obj["spec"]["maxUnavailable"]
+            logger.debug(
+                f"{resource.kind} {resource.namespace}/{resource.name} has {replicas} maxUnavailable (original: {original_replicas}, uptime: {uptime})"
+            )
+        else:
+            replicas = 0
+            logger.debug(
+                f"{resource.kind} {resource.namespace}/{resource.name} has neither minAvailable nor maxUnavailable (original: {original_replicas}, uptime: {uptime})"
+            )
     elif resource.kind == "HorizontalPodAutoscaler":
         replicas = resource.obj["spec"]["minReplicas"]
         logger.debug(
@@ -195,6 +212,17 @@ def scale_up(
             f"Unsuspending {resource.kind} {resource.namespace}/{resource.name} (uptime: {uptime}, downtime: {downtime})"
         )
         event_message = "Unsuspending CronJob"
+    elif resource.kind == "PodDisruptionBudget":
+        if "minAvailable" in resource.obj["spec"]:
+            resource.obj["spec"]["minAvailable"] = original_replicas
+            logger.info(
+                f"Scaling up {resource.kind} {resource.namespace}/{resource.name} from {replicas} to {original_replicas} minAvailable (uptime: {uptime}, downtime: {downtime})"
+            )
+        elif "maxUnavailable" in resource.obj["spec"]:
+            resource.obj["spec"]["maxUnavailable"] = original_replicas
+            logger.info(
+                f"Scaling up {resource.kind} {resource.namespace}/{resource.name} from {replicas} to {original_replicas} maxUnavailable (uptime: {uptime}, downtime: {downtime})"
+            )
     elif resource.kind == "HorizontalPodAutoscaler":
         resource.obj["spec"]["minReplicas"] = original_replicas
         logger.info(
@@ -247,6 +275,17 @@ def scale_down(
             f"Suspending {resource.kind} {resource.namespace}/{resource.name} (uptime: {uptime}, downtime: {downtime})"
         )
         event_message = "Suspending CronJob"
+    elif resource.kind == "PodDisruptionBudget":
+        if "minAvailable" in resource.obj["spec"]:
+            resource.obj["spec"]["minAvailable"] = target_replicas
+            logger.info(
+                f"Scaling down {resource.kind} {resource.namespace}/{resource.name} from {replicas} to {target_replicas} minAvailable (uptime: {uptime}, downtime: {downtime})"
+            )
+        elif "maxUnavailable" in resource.obj["spec"]:
+            resource.obj["spec"]["maxUnavailable"] = target_replicas
+            logger.info(
+                f"Scaling down {resource.kind} {resource.namespace}/{resource.name} from {replicas} to {target_replicas} maxUnavailable (uptime: {uptime}, downtime: {downtime})"
+            )
     elif resource.kind == "HorizontalPodAutoscaler":
         resource.obj["spec"]["minReplicas"] = target_replicas
         logger.info(

tests/test_autoscale_resource.py

@@ -6,7 +6,7 @@
 
 import pykube
 import pytest
-from pykube import Deployment
+from pykube import Deployment, PodDisruptionBudget
 from pykube import HorizontalPodAutoscaler
 
 from kube_downscaler.resources.stack import Stack
@@ -865,3 +865,131 @@ def test_upscale_hpa_with_autoscaling():
     )
     assert hpa.obj["spec"]["minReplicas"] == 4
     assert hpa.obj["metadata"]["annotations"][ORIGINAL_REPLICAS_ANNOTATION] is None
+
+def test_downscale_pdb_minavailable_with_autoscaling():
+    pdb = PodDisruptionBudget(
+        None,
+        {
+            "metadata": {
+                "name": "my-pdb",
+                "namespace": "my-ns",
+                "creationTimestamp": "2018-10-23T21:55:00Z",
+                "annotations": {DOWNTIME_REPLICAS_ANNOTATION: str(1)},
+            },
+            "spec": {"minAvailable": 4},
+        },
+    )
+    now = datetime.strptime("2018-10-23T21:56:00Z", "%Y-%m-%dT%H:%M:%SZ").replace(
+        tzinfo=timezone.utc
+    )
+    autoscale_resource(
+        pdb,
+        upscale_period="never",
+        downscale_period="never",
+        default_uptime="never",
+        default_downtime="always",
+        forced_uptime=False,
+        forced_downtime=False,
+        dry_run=True,
+        now=now,
+    )
+    assert pdb.obj["spec"]["minAvailable"] == 1
+    assert pdb.obj["metadata"]["annotations"][ORIGINAL_REPLICAS_ANNOTATION] == str(4)
+
+
+def test_upscale_pdb_minavailable_with_autoscaling():
+    pdb = PodDisruptionBudget(
+        None,
+        {
+            "metadata": {
+                "name": "my-pdb",
+                "namespace": "my-ns",
+                "creationTimestamp": "2018-10-23T21:55:00Z",
+                "annotations": {
+                    DOWNTIME_REPLICAS_ANNOTATION: str(1),
+                    ORIGINAL_REPLICAS_ANNOTATION: str(4),
+                },
+            },
+            "spec": {"minAvailable": 1},
+        },
+    )
+    now = datetime.strptime("2018-10-23T22:15:00Z", "%Y-%m-%dT%H:%M:%SZ").replace(
+        tzinfo=timezone.utc
+    )
+    autoscale_resource(
+        pdb,
+        upscale_period="never",
+        downscale_period="never",
+        default_uptime="always",
+        default_downtime="never",
+        forced_uptime=False,
+        forced_downtime=False,
+        dry_run=True,
+        now=now,
+    )
+    assert pdb.obj["spec"]["minAvailable"] == 4
+    assert pdb.obj["metadata"]["annotations"][ORIGINAL_REPLICAS_ANNOTATION] is None
+
+def test_downscale_pdb_maxunavailable_with_autoscaling():
+    pdb = PodDisruptionBudget(
+        None,
+        {
+            "metadata": {
+                "name": "my-pdb",
+                "namespace": "my-ns",
+                "creationTimestamp": "2018-10-23T21:55:00Z",
+                "annotations": {DOWNTIME_REPLICAS_ANNOTATION: str(1)},
+            },
+            "spec": {"maxUnavailable": 4},
+        },
+    )
+    now = datetime.strptime("2018-10-23T21:56:00Z", "%Y-%m-%dT%H:%M:%SZ").replace(
+        tzinfo=timezone.utc
+    )
+    autoscale_resource(
+        pdb,
+        upscale_period="never",
+        downscale_period="never",
+        default_uptime="never",
+        default_downtime="always",
+        forced_uptime=False,
+        forced_downtime=False,
+        dry_run=True,
+        now=now,
+    )
+    assert pdb.obj["spec"]["maxUnavailable"] == 1
+    assert pdb.obj["metadata"]["annotations"][ORIGINAL_REPLICAS_ANNOTATION] == str(4)
+
+
+def test_upscale_pdb_maxunavailable_with_autoscaling():
+    pdb = PodDisruptionBudget(
+        None,
+        {
+            "metadata": {
+                "name": "my-pdb",
+                "namespace": "my-ns",
+                "creationTimestamp": "2018-10-23T21:55:00Z",
+                "annotations": {
+                    DOWNTIME_REPLICAS_ANNOTATION: str(1),
+                    ORIGINAL_REPLICAS_ANNOTATION: str(4),
+                },
+            },
+            "spec": {"maxUnavailable": 1},
+        },
+    )
+    now = datetime.strptime("2018-10-23T22:15:00Z", "%Y-%m-%dT%H:%M:%SZ").replace(
+        tzinfo=timezone.utc
+    )
+    autoscale_resource(
+        pdb,
+        upscale_period="never",
+        downscale_period="never",
+        default_uptime="always",
+        default_downtime="never",
+        forced_uptime=False,
+        forced_downtime=False,
+        dry_run=True,
+        now=now,
+    )
+    assert pdb.obj["spec"]["maxUnavailable"] == 4
+    assert pdb.obj["metadata"]["annotations"][ORIGINAL_REPLICAS_ANNOTATION] is None

tests/test_cmd.py

@@ -19,6 +19,6 @@ def test_check_include_resources_invalid():
     with pytest.raises(Exception) as excinfo:
         check_include_resources("deployments,foo")
     assert (
-        "--include-resources argument should contain a subset of [cronjobs, deployments, horizontalpodautoscalers, rollouts, scaledobjects, stacks, statefulsets]"
+        "--include-resources argument should contain a subset of [cronjobs, deployments, horizontalpodautoscalers, poddisruptionbudgets, rollouts, scaledobjects, stacks, statefulsets]"
         in str(excinfo.value)
     )