test(breakfix): implement BFX01-04 cordon validation

isvctl/configs/providers/my-isv/scripts/breakfix/cordon_node.py

@@ -2,36 +2,323 @@
 # SPDX-FileCopyrightText: Copyright (c) 2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
 # SPDX-License-Identifier: Apache-2.0
 
-"""Cordon a Kubernetes node (BFX01-04) - my-isv template."""
+"""Exercise Kubernetes node cordoning semantics for BFX01-04."""
 
 from __future__ import annotations
 
 import argparse
+import json
+import os
+import shlex
+import subprocess
 import sys
-from pathlib import Path
+import time
+import uuid
+from typing import Any
 
-sys.path.insert(0, str(Path(__file__).resolve().parent))
-from _stub import base_result, demo_or_not_implemented, finish
+DEFAULT_IMAGE = "registry.k8s.io/pause:3.10"
 
 
-def main() -> int:
-    """Emit the cordon-node template result (BFX01-04)."""
-    parser = argparse.ArgumentParser(description="Cordon node (template)")
-    parser.add_argument("--region", default="", help="Cloud region")
-    _ = parser.parse_args()
+class CordonTestError(RuntimeError):
+    """Raised when the cordon workflow cannot prove the required behavior."""
+
+
+def _kubectl_command() -> list[str]:
+    """Return the configured kubectl-compatible command prefix."""
+    configured = os.environ.get("KUBECTL", "kubectl")
+    try:
+        command = shlex.split(configured)
+    except ValueError as exc:
+        raise CordonTestError(f"Invalid KUBECTL value: {exc}") from exc
+    if not command:
+        raise CordonTestError("KUBECTL must not be blank")
+    return command
+
+
+def _run(
+    kubectl: list[str],
+    *args: str,
+    input_text: str | None = None,
+    check: bool = True,
+) -> subprocess.CompletedProcess[str]:
+    """Run kubectl and raise a concise error when the command fails."""
+    try:
+        completed = subprocess.run(
+            [*kubectl, *args],
+            input=input_text,
+            capture_output=True,
+            text=True,
+            check=False,
+        )
+    except OSError as exc:
+        raise CordonTestError(f"Unable to run {' '.join(kubectl)}: {exc}") from exc
+    if check and completed.returncode != 0:
+        detail = (completed.stderr or completed.stdout).strip()
+        detail = detail[-500:] if detail else "command failed without output"
+        raise CordonTestError(f"kubectl {' '.join(args)} failed: {detail}")
+    return completed
+
+
+def _json_output(completed: subprocess.CompletedProcess[str], resource: str) -> dict[str, Any]:
+    """Parse one kubectl JSON object."""
+    try:
+        payload = json.loads(completed.stdout)
+    except json.JSONDecodeError as exc:
+        raise CordonTestError(f"kubectl returned invalid JSON for {resource}") from exc
+    if not isinstance(payload, dict):
+        raise CordonTestError(f"kubectl returned a non-object for {resource}")
+    return payload
+
+
+def _node_is_ready(node: dict[str, Any]) -> bool:
+    """Return whether a node is Ready, schedulable, and available for the test."""
+    conditions = node.get("status", {}).get("conditions", [])
+    ready = any(item.get("type") == "Ready" and item.get("status") == "True" for item in conditions)
+    return ready and not node.get("spec", {}).get("unschedulable", False)
+
 
-    result = demo_or_not_implemented(
+def _select_node(kubectl: list[str], requested_node: str | None) -> tuple[str, str, list[dict[str, str]]]:
+    """Select a schedulable Ready node and return its identity and required tolerations."""
+    payload = _json_output(_run(kubectl, "get", "nodes", "-o", "json"), "node list")
+    items = payload.get("items")
+    if not isinstance(items, list):
+        raise CordonTestError("kubectl node list is missing items")
+
+    candidates = [node for node in items if isinstance(node, dict) and _node_is_ready(node)]
+    if requested_node:
+        candidates = [node for node in candidates if node.get("metadata", {}).get("name") == requested_node]
+        if not candidates:
+            raise CordonTestError(f"Requested node {requested_node!r} is not Ready and schedulable")
+    if not candidates:
+        raise CordonTestError("No Ready, schedulable node is available for the cordon test")
+
+    node = candidates[0]
+    metadata = node.get("metadata", {})
+    name = metadata.get("name")
+    hostname = metadata.get("labels", {}).get("kubernetes.io/hostname")
+    if not isinstance(name, str) or not name:
+        raise CordonTestError("Selected node is missing metadata.name")
+    if not isinstance(hostname, str) or not hostname:
+        raise CordonTestError(f"Node {name!r} is missing the kubernetes.io/hostname label")
+    tolerations = []
+    for taint in node.get("spec", {}).get("taints", []):
+        key = taint.get("key")
+        effect = taint.get("effect")
+        if not isinstance(key, str) or effect not in {"NoSchedule", "NoExecute"}:
+            continue
+        if key == "node.kubernetes.io/unschedulable":
+            continue
+        tolerations.append(
+            {
+                "key": key,
+                "operator": "Equal",
+                "value": str(taint.get("value", "")),
+                "effect": effect,
+            }
+        )
+    return name, hostname, tolerations
+
+
+def _pod_manifest(
+    name: str,
+    namespace: str,
+    hostname: str,
+    image: str,
+    tolerations: list[dict[str, str]],
+) -> str:
+    """Build a minimal long-running pod constrained to one node hostname."""
+    return json.dumps(
         {
-            **base_result("cordon_node"),
-            "operation": {
-                "cordoned": True,
-                "new_workloads_blocked": True,
-                "existing_workloads_running": True,
+            "apiVersion": "v1",
+            "kind": "Pod",
+            "metadata": {
+                "name": name,
+                "namespace": namespace,
+                "labels": {
+                    "app.kubernetes.io/managed-by": "isvtest",
+                    "isvtest.nvidia.com/purpose": "bfx01-04",
+                },
+            },
+            "spec": {
+                "restartPolicy": "Never",
+                "nodeSelector": {"kubernetes.io/hostname": hostname},
+                "tolerations": tolerations,
+                "containers": [{"name": "probe", "image": image}],
             },
-        },
-        hint="cordon node breakfix API",
+        }
     )
-    return finish(result)
+
+
+def _get_pod(kubectl: list[str], namespace: str, name: str) -> dict[str, Any]:
+    """Return one pod as a JSON object."""
+    completed = _run(kubectl, "get", "pod", name, "-n", namespace, "-o", "json")
+    return _json_output(completed, f"pod {namespace}/{name}")
+
+
+def _pod_is_ready_on_node(pod: dict[str, Any], node_name: str) -> bool:
+    """Return whether a pod is still Ready and bound to the expected node."""
+    if pod.get("spec", {}).get("nodeName") != node_name or pod.get("status", {}).get("phase") != "Running":
+        return False
+    conditions = pod.get("status", {}).get("conditions", [])
+    return any(item.get("type") == "Ready" and item.get("status") == "True" for item in conditions)
+
+
+def _pod_is_unschedulable(pod: dict[str, Any]) -> bool:
+    """Return whether the scheduler explicitly reported the pod unschedulable."""
+    if pod.get("spec", {}).get("nodeName"):
+        return False
+    conditions = pod.get("status", {}).get("conditions", [])
+    return any(
+        item.get("type") == "PodScheduled" and item.get("status") == "False" and item.get("reason") == "Unschedulable"
+        for item in conditions
+    )
+
+
+def _wait_for_unschedulable(
+    kubectl: list[str],
+    namespace: str,
+    name: str,
+    timeout_seconds: float,
+    poll_interval_seconds: float,
+) -> bool:
+    """Poll until Kubernetes reports that the new probe cannot be scheduled."""
+    deadline = time.monotonic() + timeout_seconds
+    while True:
+        if _pod_is_unschedulable(_get_pod(kubectl, namespace, name)):
+            return True
+        if time.monotonic() >= deadline:
+            return False
+        time.sleep(poll_interval_seconds)
+
+
+def _cleanup(kubectl: list[str], namespace: str, pod_names: list[str], node_name: str | None) -> list[str]:
+    """Delete probe pods and restore node schedulability, returning any errors."""
+    errors: list[str] = []
+    for pod_name in pod_names:
+        try:
+            completed = _run(
+                kubectl,
+                "delete",
+                "pod",
+                pod_name,
+                "-n",
+                namespace,
+                "--ignore-not-found=true",
+                "--wait=false",
+                check=False,
+            )
+        except CordonTestError as exc:
+            errors.append(f"delete pod {namespace}/{pod_name}: {exc}")
+            continue
+        if completed.returncode != 0:
+            errors.append(f"delete pod {namespace}/{pod_name}: {(completed.stderr or completed.stdout).strip()}")
+    if node_name:
+        try:
+            completed = _run(kubectl, "uncordon", node_name, check=False)
+        except CordonTestError as exc:
+            errors.append(f"uncordon node {node_name}: {exc}")
+        else:
+            if completed.returncode != 0:
+                errors.append(f"uncordon node {node_name}: {(completed.stderr or completed.stdout).strip()}")
+    return errors
+
+
+def _parser() -> argparse.ArgumentParser:
+    """Build the command-line parser."""
+    parser = argparse.ArgumentParser(description="Cordon a node and verify Kubernetes scheduling behavior")
+    parser.add_argument("--region", default="", help="Accepted for provider config compatibility")
+    parser.add_argument("--node", help="Specific Ready, schedulable node to test")
+    parser.add_argument("--namespace", default="default", help="Namespace for temporary probe pods")
+    parser.add_argument("--image", default=DEFAULT_IMAGE, help="Container image for temporary probe pods")
+    parser.add_argument("--timeout-seconds", type=float, default=120, help="Timeout for each scheduling assertion")
+    parser.add_argument("--poll-interval-seconds", type=float, default=2, help="Pending-pod polling interval")
+    return parser
+
+
+def main() -> int:
+    """Run the reversible cordon test and emit its provider-neutral JSON result."""
+    args = _parser().parse_args()
+    operation: dict[str, Any] = {
+        "cordoned": False,
+        "new_workloads_blocked": False,
+        "existing_workloads_running": False,
+    }
+    result: dict[str, Any] = {"success": False, "platform": "my-isv", "test_name": "cordon_node"}
+    kubectl: list[str] = []
+    created_pods: list[str] = []
+    cordoned_node: str | None = None
+
+    try:
+        if args.timeout_seconds <= 0 or args.poll_interval_seconds <= 0:
+            raise CordonTestError("Timeout and poll interval must be greater than zero")
+        kubectl = _kubectl_command()
+        node_name, hostname, tolerations = _select_node(kubectl, args.node)
+        operation["node_id"] = node_name
+        suffix = uuid.uuid4().hex[:8]
+        existing_pod = f"isvtest-bfx-existing-{suffix}"
+        blocked_pod = f"isvtest-bfx-blocked-{suffix}"
+
+        _run(
+            kubectl,
+            "create",
+            "-f",
+            "-",
+            input_text=_pod_manifest(existing_pod, args.namespace, hostname, args.image, tolerations),
+        )
+        created_pods.append(existing_pod)
+        _run(
+            kubectl,
+            "wait",
+            "--for=condition=Ready",
+            f"pod/{existing_pod}",
+            "-n",
+            args.namespace,
+            f"--timeout={args.timeout_seconds:g}s",
+        )
+
+        _run(kubectl, "cordon", node_name)
+        cordoned_node = node_name
+        node = _json_output(_run(kubectl, "get", "node", node_name, "-o", "json"), f"node {node_name}")
+        operation["cordoned"] = node.get("spec", {}).get("unschedulable") is True
+        if not operation["cordoned"]:
+            raise CordonTestError(f"Node {node_name!r} was not marked unschedulable")
+
+        operation["existing_workloads_running"] = _pod_is_ready_on_node(
+            _get_pod(kubectl, args.namespace, existing_pod), node_name
+        )
+        if not operation["existing_workloads_running"]:
+            raise CordonTestError("Existing probe pod did not remain Ready on the cordoned node")
+
+        _run(
+            kubectl,
+            "create",
+            "-f",
+            "-",
+            input_text=_pod_manifest(blocked_pod, args.namespace, hostname, args.image, tolerations),
+        )
+        created_pods.append(blocked_pod)
+        operation["new_workloads_blocked"] = _wait_for_unschedulable(
+            kubectl,
+            args.namespace,
+            blocked_pod,
+            args.timeout_seconds,
+            args.poll_interval_seconds,
+        )
+        if not operation["new_workloads_blocked"]:
+            raise CordonTestError("New probe pod was not confirmed unschedulable on the cordoned node")
+        result["success"] = True
+    except CordonTestError as exc:
+        result["error"] = str(exc)
+    finally:
+        cleanup_errors = _cleanup(kubectl, args.namespace, created_pods, cordoned_node) if kubectl else []
+        if cleanup_errors:
+            result["success"] = False
+            result["cleanup_errors"] = cleanup_errors
+            result.setdefault("error", "Cordon test cleanup failed")
+
+    result["operation"] = operation
+    print(json.dumps(result, indent=2))
+    return 0 if result["success"] else 1
 
 
 if __name__ == "__main__":