feat: storage I/O throttle scenario (cgroups v1/v2) for PVC-backed workloads (#1296)

* feat(storage-throttle): add storage throttle scenario and tests

Consolidate the storage-throttle implementation, scenario configs, CI v2 coverage, and krkn-lib 6.0.10 dependency update into a single signed commit for cleaner PR history.

Signed-off-by: ddjain <darjain@redhat.com>
Co-authored-by: Cursor <cursoragent@cursor.com>
Signed-off-by: ddjain <darjain@redhat.com>

* adding need dco auto review (#1329)

Signed-off-by: Paige Patton <prubenda@redhat.com>
Signed-off-by: ddjain <darjain@redhat.com>

* fix: start_klusterlet_scenario action calls start instead of stop (#1324)

The start_klusterlet_scenario branch in inject_managedcluster_scenario
was calling stop_klusterlet_scenario on the scenarios object instead of
start_klusterlet_scenario. Any user configuring this action would stop
the klusterlet (scale to 0) instead of starting it (scale to 3).

Fixes #1323

Signed-off-by: v0idheaven <dahiyavarun2007@gmail.com>
Co-authored-by: Paige Patton <64206430+paigerube14@users.noreply.github.com>
Signed-off-by: ddjain <darjain@redhat.com>

* adding links to issue of completed roadmap items (#1328)

Signed-off-by: Paige Patton <prubenda@redhat.com>
Signed-off-by: ddjain <darjain@redhat.com>

* container scenario template image update (#1342)

Signed-off-by: Paige Patton <prubenda@redhat.com>
Signed-off-by: ddjain <darjain@redhat.com>

---------

Signed-off-by: ddjain <darjain@redhat.com>
Signed-off-by: Paige Patton <prubenda@redhat.com>
Signed-off-by: v0idheaven <dahiyavarun2007@gmail.com>
Co-authored-by: Cursor <cursoragent@cursor.com>
Co-authored-by: Paige Patton <64206430+paigerube14@users.noreply.github.com>
Co-authored-by: Varun Yadav <dahiyavarun2007@gmail.com>

CI/tests_v2/pytest.ini

@@ -9,6 +9,7 @@ markers =
     functional: marks a test as a functional test (deselect with '-m "not functional"')
     pod_disruption: marks a test as a pod disruption scenario test
     application_outage: marks a test as an application outage scenario test
+    storage_throttle: marks a test as a storage throttle scenario test
     no_workload: skip workload deployment for this test (e.g. negative tests)
     order: set test order (pytest-order)
 junit_family = xunit2

CI/tests_v2/scenarios/storage_throttle/resource.yaml

@@ -0,0 +1,39 @@
+# PVC + Deployment for storage throttle integration test.
+# Namespace is patched at deploy time by the test framework.
+# Uses the default StorageClass (e.g. local-path on KinD).
+apiVersion: v1
+kind: PersistentVolumeClaim
+metadata:
+  name: krkn-throttle-pvc
+spec:
+  accessModes:
+    - ReadWriteOnce
+  resources:
+    requests:
+      storage: 128Mi
+---
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: krkn-throttle-target
+spec:
+  replicas: 1
+  selector:
+    matchLabels:
+      app: krkn-throttle-target
+  template:
+    metadata:
+      labels:
+        app: krkn-throttle-target
+    spec:
+      containers:
+      - name: app
+        image: nginx:alpine
+        command: ["/bin/sh", "-c", "trap : TERM INT; sleep infinity & wait"]
+        volumeMounts:
+        - name: data
+          mountPath: /data
+      volumes:
+      - name: data
+        persistentVolumeClaim:
+          claimName: krkn-throttle-pvc

CI/tests_v2/scenarios/storage_throttle/scenario_base.yaml

@@ -0,0 +1,13 @@
+# Base storage_throttle scenario. Tests load this and patch namespace, pvc_name, etc.
+storage_throttle_scenario:
+  pvc_name: krkn-throttle-pvc
+  pod_name: ""
+  namespace: default
+  mount_path: /data
+  throttle_type: bandwidth
+  read_bps: 1Mi
+  write_bps: 512Ki
+  read_iops: 100
+  write_iops: 50
+  duration: 15
+  image: quay.io/krkn-chaos/krkn:tools

CI/tests_v2/scenarios/storage_throttle/test_storage_throttle.py

@@ -0,0 +1,139 @@
+"""
+Functional test for storage throttle scenario (cgroup I/O throttle on PVC-backed volume).
+
+Deploys a PVC + Deployment in an ephemeral namespace, runs the storage_throttle
+scenario, and verifies:
+  - Krkn exits 0 (throttle applied and removed cleanly)
+  - Target pods survive (running and ready after scenario)
+  - Negative cases: bad namespace and invalid throttle_type fail gracefully
+
+Follows the CI/tests_v2 BaseScenarioTest pattern.
+"""
+
+import pytest
+
+from lib.base import BaseScenarioTest, READINESS_TIMEOUT
+from lib.utils import (
+    assert_all_pods_running_and_ready,
+    assert_kraken_failure,
+    assert_kraken_success,
+    assert_pod_count_unchanged,
+    get_pods_list,
+)
+
+
+@pytest.mark.functional
+@pytest.mark.storage_throttle
+class TestStorageThrottle(BaseScenarioTest):
+    """Storage throttle scenario: apply I/O cgroup limits on a PVC mount and verify recovery."""
+
+    WORKLOAD_MANIFEST = "CI/tests_v2/scenarios/storage_throttle/resource.yaml"
+    WORKLOAD_IS_PATH = True
+    LABEL_SELECTOR = "app=krkn-throttle-target"
+    SCENARIO_NAME = "storage_throttle"
+    SCENARIO_TYPE = "storage_throttle_scenarios"
+    NAMESPACE_KEY_PATH = ["storage_throttle_scenario", "namespace"]
+    NAMESPACE_IS_REGEX = False
+    OVERRIDES_KEY_PATH = ["storage_throttle_scenario"]
+
+    @pytest.mark.order(1)
+    def test_bandwidth_throttle_and_recovery(self, wait_for_pods_running):
+        """Bandwidth throttle: apply read/write bps limits, verify Krkn success and pod recovery."""
+        ns = self.ns
+        before = get_pods_list(self.k8s_core, ns, self.LABEL_SELECTOR)
+
+        result = self.run_scenario(self.tmp_path, ns, overrides={
+            "throttle_type": "bandwidth",
+            "read_bps": "1Mi",
+            "write_bps": "512Ki",
+            "duration": 15,
+        })
+        assert_kraken_success(result, context=f"bandwidth namespace={ns}", tmp_path=self.tmp_path)
+
+        wait_for_pods_running(ns, self.LABEL_SELECTOR, timeout=READINESS_TIMEOUT)
+        after = get_pods_list(self.k8s_core, ns, self.LABEL_SELECTOR)
+        assert_pod_count_unchanged(before, after, namespace=ns)
+        assert_all_pods_running_and_ready(after, namespace=ns)
+
+    @pytest.mark.order(2)
+    def test_iops_throttle_and_recovery(self, wait_for_pods_running):
+        """IOPS throttle: apply read/write iops limits, verify Krkn success and pod recovery."""
+        ns = self.ns
+        before = get_pods_list(self.k8s_core, ns, self.LABEL_SELECTOR)
+
+        result = self.run_scenario(
+            self.tmp_path, ns,
+            overrides={
+                "throttle_type": "iops",
+                "read_iops": 50,
+                "write_iops": 25,
+                "duration": 15,
+            },
+            config_filename="test_iops_config.yaml",
+        )
+        assert_kraken_success(result, context=f"iops namespace={ns}", tmp_path=self.tmp_path)
+
+        wait_for_pods_running(ns, self.LABEL_SELECTOR, timeout=READINESS_TIMEOUT)
+        after = get_pods_list(self.k8s_core, ns, self.LABEL_SELECTOR)
+        assert_pod_count_unchanged(before, after, namespace=ns)
+        assert_all_pods_running_and_ready(after, namespace=ns)
+
+    @pytest.mark.order(3)
+    def test_both_throttle_and_recovery(self, wait_for_pods_running):
+        """Combined throttle: apply both bps and iops limits, verify Krkn success and pod recovery."""
+        ns = self.ns
+        before = get_pods_list(self.k8s_core, ns, self.LABEL_SELECTOR)
+
+        result = self.run_scenario(
+            self.tmp_path, ns,
+            overrides={
+                "throttle_type": "both",
+                "read_bps": "1Mi",
+                "write_bps": "512Ki",
+                "read_iops": 50,
+                "write_iops": 25,
+                "duration": 15,
+            },
+            config_filename="test_both_config.yaml",
+        )
+        assert_kraken_success(result, context=f"both namespace={ns}", tmp_path=self.tmp_path)
+
+        wait_for_pods_running(ns, self.LABEL_SELECTOR, timeout=READINESS_TIMEOUT)
+        after = get_pods_list(self.k8s_core, ns, self.LABEL_SELECTOR)
+        assert_pod_count_unchanged(before, after, namespace=ns)
+        assert_all_pods_running_and_ready(after, namespace=ns)
+
+    @pytest.mark.no_workload
+    def test_bad_namespace_fails(self):
+        """Scenario targeting non-existent namespace causes Krkn to exit non-zero."""
+        scenario = self.load_and_patch_scenario(
+            self.repo_root, "nonexistent-namespace-xyz-99999",
+            pod_name="nonexistent-pod",
+        )
+        scenario_path = self.write_scenario(self.tmp_path, scenario, suffix="_bad_ns")
+        config_path = self.build_config(
+            self.SCENARIO_TYPE, str(scenario_path),
+            filename="storage_throttle_bad_ns_config.yaml",
+        )
+        result = self.run_kraken(config_path)
+        assert_kraken_failure(
+            result, context=f"bad namespace test", tmp_path=self.tmp_path,
+        )
+
+    @pytest.mark.no_workload
+    def test_invalid_throttle_type_fails(self):
+        """Invalid throttle_type causes Krkn to exit non-zero."""
+        scenario = self.load_and_patch_scenario(
+            self.repo_root, self.ns,
+            throttle_type="invalid_type",
+            pod_name="doesnt-matter",
+        )
+        scenario_path = self.write_scenario(self.tmp_path, scenario, suffix="_bad_type")
+        config_path = self.build_config(
+            self.SCENARIO_TYPE, str(scenario_path),
+            filename="storage_throttle_bad_type_config.yaml",
+        )
+        result = self.run_kraken(config_path)
+        assert_kraken_failure(
+            result, context=f"invalid throttle_type test", tmp_path=self.tmp_path,
+        )