#!/usr/bin/env python3 """Disk-health / node-removal-safety report for a Gallium cluster. The question this answers: **is it safe to remove a node** (permanently, or temporarily for maintenance)? A node is unsafe to remove when some volume's last healthy copy of its data lives only on that node -- removing it would take that data offline (permanently, or for the duration of the maintenance). Data model (all read live via `kubectl`): * KubeVirt VirtualMachines / VirtualMachineInstances -- the VMs and whether they're running, and which node each runs on. * The PVCs each VM references (directly, via DataVolume, or hot-plugged). * Longhorn Volumes + Replicas -- for every PVC's underlying volume, where its replicas live (which node) and whether each replica is healthy. * Pods -- to attribute PVCs that aren't owned by a VM to a non-VM workload vs. nothing at all. The report has three parts: 1. A per-node removal-safety summary (the headline -- SAFE / UNSAFE). 2. Per-VM detail: the VM, its running state, and for each of its PVCs a table of (replica, node, health). 3. PVCs not attached to any VM, split into "attached to a non-VM pod" and "completely detached". Self-contained: standard library only; the sole dependency is a `kubectl` binary that can reach the cluster. """ from __future__ import annotations import argparse import json import subprocess import sys from collections import defaultdict from dataclasses import dataclass, field LONGHORN_NS = "longhorn-system" LONGHORN_CSI_DRIVER = "driver.longhorn.io" # --------------------------------------------------------------------------- # # kubectl plumbing # --------------------------------------------------------------------------- # class Kubectl: """Thin wrapper that shells out to kubectl and parses JSON.""" def __init__(self, binary: str, kubeconfig: str | None, context: str | None): self.base = [binary] if kubeconfig: self.base += ["--kubeconfig", kubeconfig] if context: self.base += ["--context", context] def get(self, resource: str, namespace: str | None = None) -> list[dict]: """`kubectl get -o json` -> list of items. Returns [] (with a warning) when the resource type isn't present -- e.g. a cluster without KubeVirt or Longhorn installed -- rather than aborting the whole report. """ cmd = list(self.base) + ["get", resource, "-o", "json"] cmd += ["-n", namespace] if namespace else ["-A"] proc = subprocess.run(cmd, capture_output=True, text=True) if proc.returncode != 0: err = proc.stderr.strip() low = err.lower() if "the server doesn't have a resource type" in low or "could not find" in low: warn(f"resource {resource!r} not found on the cluster; skipping ({err})") return [] die(f"kubectl get {resource} failed: {err}") try: return json.loads(proc.stdout).get("items", []) except json.JSONDecodeError as exc: die(f"could not parse kubectl output for {resource}: {exc}") return [] # --------------------------------------------------------------------------- # # colour / output helpers # --------------------------------------------------------------------------- # class C: """ANSI colour codes; blanked out when colour is disabled.""" RESET = BOLD = DIM = RED = GREEN = YELLOW = BLUE = CYAN = "" @classmethod def enable(cls): cls.RESET = "\033[0m" cls.BOLD = "\033[1m" cls.DIM = "\033[2m" cls.RED = "\033[31m" cls.GREEN = "\033[32m" cls.YELLOW = "\033[33m" cls.BLUE = "\033[34m" cls.CYAN = "\033[36m" def warn(msg: str): print(f"{C.YELLOW}warning:{C.RESET} {msg}", file=sys.stderr) def die(msg: str): print(f"{C.RED}error:{C.RESET} {msg}", file=sys.stderr) sys.exit(1) def render_table(headers: list[str], rows: list[list[str]], indent: str = " ") -> str: """Render a simple fixed-width table. Colour codes are ignored for width.""" import re ansi = re.compile(r"\033\[[0-9;]*m") def vlen(s: str) -> int: return len(ansi.sub("", s)) widths = [vlen(h) for h in headers] for row in rows: for i, cell in enumerate(row): widths[i] = max(widths[i], vlen(cell)) def fmt(row: list[str]) -> str: cells = [] for i, cell in enumerate(row): cells.append(cell + " " * (widths[i] - vlen(cell))) return indent + " ".join(cells).rstrip() sep = indent + " ".join("-" * w for w in widths) out = [fmt([f"{C.BOLD}{h}{C.RESET}" for h in headers]), sep] out += [fmt(r) for r in rows] return "\n".join(out) # --------------------------------------------------------------------------- # # domain types # --------------------------------------------------------------------------- # HEALTHY = "healthy" @dataclass class Replica: name: str node: str health: str # display: healthy | stopped | rebuilding | failed | error | unknown has_data: bool # holds a usable copy of the data (healthyAt set, not failed) @dataclass class Volume: """A Longhorn volume backing one PVC (or a non-Longhorn PVC's stand-in).""" pvc_ns: str pvc_name: str lh_name: str | None # Longhorn volume name (== bound PV name) storage_class: str robustness: str # healthy | degraded | faulted | unknown | - state: str # attached | detached | - desired_replicas: int | None replicas: list[Replica] = field(default_factory=list) note: str = "" # e.g. non-Longhorn, unbound, missing @property def data_nodes(self) -> set[str]: """Nodes that hold a usable copy of this volume's data. Uses data validity (healthyAt && !failedAt), NOT engine-running state: a cleanly-detached volume (stopped VM) still has good copies on its replica nodes, so losing one of those nodes still loses data. """ return {r.node for r in self.replicas if r.has_data and r.node} @property def all_nodes(self) -> set[str]: return {r.node for r in self.replicas if r.node} @dataclass class VM: ns: str name: str status: str # Running | Stopped | ... node: str | None # node the VMI runs on pvcs: list[tuple[str, str]] # (ns, name) referenced by this VM @property def running(self) -> bool: return self.status == "Running" # --------------------------------------------------------------------------- # # building the model # --------------------------------------------------------------------------- # def classify_replica(rep: dict) -> tuple[str, bool]: """Return (display-health, has_data) for a Longhorn Replica CR. has_data is the data-safety signal: the replica holds a usable copy iff it has been healthy (`healthyAt`) and hasn't failed (`failedAt`) -- true even when the engine is stopped because the volume is detached. """ spec = rep.get("spec", {}) status = rep.get("status", {}) failed = bool(spec.get("failedAt")) healthy_at = bool(spec.get("healthyAt")) cur = status.get("currentState", "") has_data = healthy_at and not failed if failed: disp = "failed" elif cur == "running": disp = HEALTHY if healthy_at else "rebuilding" elif healthy_at: disp = "stopped" # good copy, engine down (volume detached) elif cur in ("stopped", "error"): disp = cur else: disp = cur or "unknown" return disp, has_data def vm_referenced_pvcs(vm_spec_volumes: list[dict], ns: str) -> list[tuple[str, str]]: """PVC (ns, name) pairs a set of KubeVirt `volumes[]` entries reference.""" out: list[tuple[str, str]] = [] for v in vm_spec_volumes or []: pvc = v.get("persistentVolumeClaim") if pvc and pvc.get("claimName"): out.append((ns, pvc["claimName"])) continue # A DataVolume materialises a PVC with the same name in the same ns. dv = v.get("dataVolume") if dv and dv.get("name"): out.append((ns, dv["name"])) return out def is_virt_launcher(pod: dict) -> bool: labels = pod.get("metadata", {}).get("labels", {}) or {} if labels.get("kubevirt.io") == "virt-launcher": return True for ref in pod.get("metadata", {}).get("ownerReferences", []) or []: if ref.get("kind") == "VirtualMachineInstance": return True return False def virt_launcher_vm_name(pod: dict) -> str: """The VM/VMI name a virt-launcher pod belongs to (VMI name == VM name).""" for ref in pod.get("metadata", {}).get("ownerReferences", []) or []: if ref.get("kind") == "VirtualMachineInstance" and ref.get("name"): return ref["name"] return (pod.get("metadata", {}).get("labels", {}) or {}).get("vm.kubevirt.io/name", "") def build_volume(pvc_ns: str, pvc_name: str, pvc_index, pv_index, lh_vol_index, replicas_by_vol) -> Volume: pvc = pvc_index.get((pvc_ns, pvc_name)) if pvc is None: return Volume(pvc_ns, pvc_name, None, "-", "-", "-", None, note="PVC not found") sc = pvc.get("spec", {}).get("storageClassName", "") or "-" pv_name = pvc.get("spec", {}).get("volumeName") or "" phase = pvc.get("status", {}).get("phase", "") if not pv_name: return Volume(pvc_ns, pvc_name, None, sc, "-", "-", None, note=f"unbound PVC (phase={phase})") pv = pv_index.get(pv_name) driver = "" if pv: driver = pv.get("spec", {}).get("csi", {}).get("driver", "") if pv and driver and driver != LONGHORN_CSI_DRIVER: # Non-Longhorn PV: its data lives wherever the PV binds (often one node). node = _pv_pinned_node(pv) note = f"non-Longhorn ({driver})" vol = Volume(pvc_ns, pvc_name, pv_name, sc, "-", "-", None, note=note) if node: vol.replicas.append(Replica(pv_name, node, HEALTHY, has_data=True)) return vol # Longhorn: the volume CR name equals the bound PV name. lh = lh_vol_index.get(pv_name) if lh is None: return Volume(pvc_ns, pvc_name, pv_name, sc, "-", "-", None, note="no Longhorn volume CR") robustness = lh.get("status", {}).get("robustness", "unknown") or "unknown" state = lh.get("status", {}).get("state", "unknown") or "unknown" desired = lh.get("spec", {}).get("numberOfReplicas") vol = Volume(pvc_ns, pvc_name, pv_name, sc, robustness, state, desired) for rep in replicas_by_vol.get(pv_name, []): # An empty nodeID means Longhorn couldn't schedule this replica (e.g. a # 3rd replica on a 2-node cluster). Keep it "" so it never counts as a # node that holds data, and render it as "(unscheduled)". node = rep.get("spec", {}).get("nodeID", "") or "" disp, has_data = classify_replica(rep) vol.replicas.append(Replica( name=rep.get("metadata", {}).get("name", "?"), node=node, health=disp, has_data=has_data, )) vol.replicas.sort(key=lambda r: (r.node, r.name)) return vol def _pv_pinned_node(pv: dict) -> str | None: """Best-effort node a non-Longhorn PV is pinned to (nodeAffinity).""" terms = (pv.get("spec", {}).get("nodeAffinity", {}) .get("required", {}).get("nodeSelectorTerms", [])) for term in terms: for expr in term.get("matchExpressions", []): if expr.get("key") == "kubernetes.io/hostname" and expr.get("values"): return expr["values"][0] return None # --------------------------------------------------------------------------- # # health formatting # --------------------------------------------------------------------------- # def colour_health(health: str) -> str: good = {HEALTHY, "attached"} warnish = {"rebuilding", "degraded", "stopped", "detached"} bad = {"failed", "faulted", "error", "unknown"} if health in good: return f"{C.GREEN}{health}{C.RESET}" if health in warnish: return f"{C.YELLOW}{health}{C.RESET}" if health in bad: return f"{C.RED}{health}{C.RESET}" return health def colour_status(status: str) -> str: if status == "Running": return f"{C.GREEN}{status}{C.RESET}" if status in ("Stopped", "Paused"): return f"{C.YELLOW}{status}{C.RESET}" return f"{C.CYAN}{status}{C.RESET}" # --------------------------------------------------------------------------- # # main report # --------------------------------------------------------------------------- # def main(): ap = argparse.ArgumentParser( description="Report Longhorn disk health and assess node-removal safety.") ap.add_argument("--kubectl", default="kubectl", help="kubectl binary to use (default: kubectl on PATH)") ap.add_argument("--kubeconfig", help="path to kubeconfig (else KUBECONFIG/default)") ap.add_argument("--context", help="kube context to use") ap.add_argument("--json", action="store_true", help="emit the structured model as JSON instead of a report") ap.add_argument("--no-color", action="store_true", help="disable ANSI colour") args = ap.parse_args() if not args.no_color and sys.stdout.isatty(): C.enable() kc = Kubectl(args.kubectl, args.kubeconfig, args.context) # --- fetch everything up front ---------------------------------------- # vms_raw = kc.get("virtualmachines.kubevirt.io") vmis_raw = kc.get("virtualmachineinstances.kubevirt.io") pvcs_raw = kc.get("persistentvolumeclaims") pvs_raw = kc.get("persistentvolumes") pods_raw = kc.get("pods") lh_vols_raw = kc.get("volumes.longhorn.io", LONGHORN_NS) lh_reps_raw = kc.get("replicas.longhorn.io", LONGHORN_NS) pvc_index = {(p["metadata"]["namespace"], p["metadata"]["name"]): p for p in pvcs_raw} pv_index = {p["metadata"]["name"]: p for p in pvs_raw} lh_vol_index = {v["metadata"]["name"]: v for v in lh_vols_raw} replicas_by_vol: dict[str, list[dict]] = defaultdict(list) for rep in lh_reps_raw: vol_name = rep.get("spec", {}).get("volumeName") if vol_name: replicas_by_vol[vol_name].append(rep) # VMI node + status lookup, keyed by (ns, name). vmi_index = {(v["metadata"]["namespace"], v["metadata"]["name"]): v for v in vmis_raw} # --- assemble VMs ------------------------------------------------------ # vms: list[VM] = [] for raw in vms_raw: ns = raw["metadata"]["namespace"] name = raw["metadata"]["name"] status = raw.get("status", {}).get("printableStatus", "") or "Unknown" spec_vols = (raw.get("spec", {}).get("template", {}) .get("spec", {}).get("volumes", [])) pvcs = vm_referenced_pvcs(spec_vols, ns) node = None vmi = vmi_index.get((ns, name)) if vmi: node = vmi.get("status", {}).get("nodeName") # Include hot-plugged / VMI-level volumes too. for extra in vm_referenced_pvcs(vmi.get("spec", {}).get("volumes", []), ns): if extra not in pvcs: pvcs.append(extra) vms.append(VM(ns, name, status, node, pvcs)) vms.sort(key=lambda v: (v.ns, v.name)) vm_by_key = {(vm.ns, vm.name): vm for vm in vms} # --- pods that mount PVCs --------------------------------------------- # # A running VM's virt-launcher pod mounts every volume the VM actually uses # -- including ones KubeVirt manages outside spec.template.spec.volumes (the # persistent-state/EFI-vars PVC, hot-plugged disks). Attribute those to the # owning VM so they show under the VM, not as "detached". Other pods are # real non-VM consumers. pods_by_pvc: dict[tuple[str, str], list[tuple[str, str]]] = defaultdict(list) for pod in pods_raw: pns = pod["metadata"]["namespace"] pnode = pod.get("spec", {}).get("nodeName", "") or "?" pname = pod["metadata"]["name"] claims = [v["persistentVolumeClaim"]["claimName"] for v in pod.get("spec", {}).get("volumes", []) or [] if v.get("persistentVolumeClaim", {}).get("claimName")] if is_virt_launcher(pod): vm = vm_by_key.get((pns, virt_launcher_vm_name(pod))) if vm is not None: for c in claims: if (pns, c) not in vm.pvcs: vm.pvcs.append((pns, c)) continue # a VM's own pod; its PVCs belong to the VM section for c in claims: pods_by_pvc[(pns, c)].append((pname, pnode)) # Set of PVCs owned by a VM (after folding in virt-launcher-mounted ones). vm_pvc_set: set[tuple[str, str]] = {p for vm in vms for p in vm.pvcs} # --- build volumes for every PVC -------------------------------------- # def vol_for(ns_name: tuple[str, str]) -> Volume: return build_volume(ns_name[0], ns_name[1], pvc_index, pv_index, lh_vol_index, replicas_by_vol) all_pvc_keys = set(pvc_index.keys()) | vm_pvc_set volumes = {k: vol_for(k) for k in all_pvc_keys} # --- node inventory ---------------------------------------------------- # nodes = sorted({r.node for v in volumes.values() for r in v.replicas if r.node}) if args.json: emit_json(vms, volumes, pods_by_pvc, vm_pvc_set, nodes) return print_node_safety(nodes, vms, volumes) print_vm_detail(vms, volumes) print_unattached(volumes, vm_pvc_set, pods_by_pvc) def _risk_line(vol: Volume) -> str: lh = vol.lh_name or "-" hn = ", ".join(sorted(vol.data_nodes)) or "(none)" return (f"{vol.pvc_ns}/{vol.pvc_name} [{lh}] " f"robustness={vol.robustness} usable-copies-on: {hn}") def print_node_safety(nodes, vms: list[VM], volumes: dict): hdr = f"{C.BOLD}=== NODE REMOVAL SAFETY ==={C.RESET}" print(hdr) if not nodes: print(" no replica-bearing nodes found (no Longhorn volumes?).\n") return # Which VM (running?) owns each PVC, for severity. running_pvcs = {p for vm in vms if vm.running for p in vm.pvcs} # Volumes already unavailable (no usable copy on any node) -- independent of # which node you remove. Reported once, globally, not per node. broken = [vol for vol in volumes.values() if vol.replicas and not vol.data_nodes] for node in nodes: crit, warns = [], [] for key, vol in volumes.items(): if not vol.replicas or not vol.data_nodes: continue if vol.data_nodes == {node}: # Removing this node drops the last usable copy. (crit if key in running_pvcs else warns).append(vol) if not crit and not warns: print(f" {C.GREEN}SAFE{C.RESET} {C.BOLD}{node}{C.RESET}: " f"every volume keeps a usable copy on another node.") continue verdict = f"{C.RED}UNSAFE{C.RESET}" if crit else f"{C.YELLOW}CAUTION{C.RESET}" print(f" {verdict} {C.BOLD}{node}{C.RESET}:") if crit: print(f" {C.RED}running-VM data lost if removed ({len(crit)}):{C.RESET}") for vol in crit: print(f" - {_risk_line(vol)}") if warns: print(f" {C.YELLOW}idle/non-VM data lost if removed ({len(warns)}):{C.RESET}") for vol in warns: print(f" - {_risk_line(vol)}") if broken: print(f"\n {C.RED}Already unavailable{C.RESET} " f"(no usable copy on ANY node -- fix before draining anything):") for vol in broken: print(f" - {_risk_line(vol)}") print() def _pvc_block(vol: Volume) -> str: head = (f" PVC {C.CYAN}{vol.pvc_ns}/{vol.pvc_name}{C.RESET}" f" vol={vol.lh_name or '-'} sc={vol.storage_class}") meta = [] if vol.robustness != "-": meta.append(f"robustness={colour_health(vol.robustness)}") if vol.state != "-": meta.append(f"state={colour_health(vol.state)}") if vol.desired_replicas is not None: meta.append(f"desired-replicas={vol.desired_replicas}") if meta: head += " (" + " ".join(meta) + ")" if vol.note: head += f" {C.DIM}[{vol.note}]{C.RESET}" lines = [head] if vol.replicas: rows = [[r.name, r.node or "(unscheduled)", colour_health(r.health)] for r in vol.replicas] lines.append(render_table(["REPLICA", "NODE", "HEALTH"], rows, indent=" ")) elif not vol.note: lines.append(f" {C.DIM}(no replicas reported){C.RESET}") return "\n".join(lines) def print_vm_detail(vms: list[VM], volumes: dict): print(f"{C.BOLD}=== VIRTUAL MACHINES ==={C.RESET}") if not vms: print(" no VirtualMachines found.\n") return for vm in vms: node = f" node={vm.node}" if vm.node else "" print(f"\n{C.BOLD}VM {vm.ns}/{vm.name}{C.RESET} " f"[{colour_status(vm.status)}]{node}") if not vm.pvcs: print(f" {C.DIM}(no PVC-backed volumes){C.RESET}") continue for key in vm.pvcs: print(_pvc_block(volumes[key])) print() def print_unattached(volumes: dict, vm_pvc_set, pods_by_pvc): non_vm = {k: v for k, v in volumes.items() if k not in vm_pvc_set} pod_attached = {k: v for k, v in non_vm.items() if pods_by_pvc.get(k)} detached = {k: v for k, v in non_vm.items() if not pods_by_pvc.get(k)} print(f"{C.BOLD}=== PVCs NOT ATTACHED TO A VM ==={C.RESET}") if not non_vm: print(" none: every PVC is attached to a VM.\n") return if pod_attached: print(f"\n {C.BOLD}Attached to non-VM pod(s):{C.RESET}") for key in sorted(pod_attached): consumers = ", ".join(f"{n} (node={nd})" for n, nd in pods_by_pvc[key]) print(f" used by: {consumers}") print(_pvc_block(pod_attached[key])) if detached: print(f"\n {C.BOLD}Completely detached (no consumer):{C.RESET}") for key in sorted(detached): print(_pvc_block(detached[key])) print() def emit_json(vms, volumes, pods_by_pvc, vm_pvc_set, nodes): def vol_dict(v: Volume): return { "pvc_namespace": v.pvc_ns, "pvc_name": v.pvc_name, "longhorn_volume": v.lh_name, "storage_class": v.storage_class, "robustness": v.robustness, "state": v.state, "desired_replicas": v.desired_replicas, "note": v.note or None, "replicas": [ {"name": r.name, "node": r.node, "health": r.health, "has_data": r.has_data} for r in v.replicas ], "usable_copy_nodes": sorted(v.data_nodes), } running_pvcs = {p for vm in vms if vm.running for p in vm.pvcs} node_safety = {} for node in nodes: crit, warns = [], [] for key, vol in volumes.items(): if vol.replicas and vol.data_nodes == {node}: (crit if key in running_pvcs else warns).append( f"{vol.pvc_ns}/{vol.pvc_name}") node_safety[node] = { "safe": not crit and not warns, "running_vm_data_only_here": crit, "other_data_only_here": warns, } out = { "nodes": nodes, "node_safety": node_safety, "vms": [ { "namespace": vm.ns, "name": vm.name, "status": vm.status, "running": vm.running, "node": vm.node, "pvcs": [f"{ns}/{n}" for ns, n in vm.pvcs], } for vm in vms ], "volumes": [vol_dict(v) for v in volumes.values()], "unattached": { f"{k[0]}/{k[1]}": { "pods": pods_by_pvc.get(k, []), "detached": not pods_by_pvc.get(k), } for k in volumes if k not in vm_pvc_set }, } print(json.dumps(out, indent=2)) if __name__ == "__main__": main()