492 lines
20 KiB
Python
Executable File
492 lines
20 KiB
Python
Executable File
#!/usr/bin/env python3
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"""Node maintenance / shutdown plan for a Gallium cluster.
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You want to take a node down -- for temporary/emergency maintenance, or to
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remove it for good. This answers: **what must I shut down (or migrate) first,
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and what data lives only on that node?**
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For each node it reports, in priority order:
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1. Shut down cleanly FIRST -- VMs that have a volume whose only usable copy is
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on this node. Taking the node down pulls that data out from under them: the
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data goes offline for the maintenance window, and is lost for good if the
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node is removed permanently. Stop these VMs cleanly (so the volume detaches
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safely) -- and replicate/move the data first if the removal is permanent.
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2. Running on this node -- VMs whose compute is here but whose data is safe on
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other nodes. Taking the node down stops them ungracefully; stop or migrate
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them for clean maintenance. (They can restart elsewhere; no data loss.)
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3. Other data only on this node -- PVCs with their only copy here that aren't
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owned by a VM (a non-VM pod's data, or a detached volume). Nothing to "shut
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down", but this data is offline during maintenance / lost on removal.
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A node with none of the above is safe to take down as-is.
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Self-contained: standard library only (Python 3.6+); the sole dependency is a
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`kubectl` binary that can reach the cluster -- so it runs unchanged on a cluster
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node (SLES / Python 3.6) or a workstation.
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"""
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import argparse
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import json
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import re
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import subprocess
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import sys
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from collections import defaultdict
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LONGHORN_NS = "longhorn-system"
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LONGHORN_CSI_DRIVER = "driver.longhorn.io"
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HEALTHY = "healthy"
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# --------------------------------------------------------------------------- #
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# kubectl plumbing
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# --------------------------------------------------------------------------- #
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class Kubectl(object):
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"""Thin wrapper that shells out to kubectl and parses JSON."""
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def __init__(self, binary, kubeconfig, context):
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self.base = [binary]
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if kubeconfig:
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self.base += ["--kubeconfig", kubeconfig]
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if context:
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self.base += ["--context", context]
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def get(self, resource, namespace=None):
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"""`kubectl get <resource> -o json` -> list of items (or [] if absent)."""
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cmd = list(self.base) + ["get", resource, "-o", "json"]
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cmd += ["-n", namespace] if namespace else ["-A"]
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proc = subprocess.run(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE,
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universal_newlines=True)
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if proc.returncode != 0:
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err = (proc.stderr or "").strip()
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low = err.lower()
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if "the server doesn't have a resource type" in low or "could not find" in low:
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warn("resource %r not found on the cluster; skipping (%s)" % (resource, err))
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return []
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die("kubectl get %s failed: %s" % (resource, err))
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try:
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return json.loads(proc.stdout).get("items", [])
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except ValueError as exc:
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die("could not parse kubectl output for %s: %s" % (resource, exc))
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return []
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# --------------------------------------------------------------------------- #
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# colour / output helpers
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# --------------------------------------------------------------------------- #
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class C(object):
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RESET = BOLD = DIM = RED = GREEN = YELLOW = BLUE = CYAN = ""
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@classmethod
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def enable(cls):
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cls.RESET = "\033[0m"
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cls.BOLD = "\033[1m"
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cls.DIM = "\033[2m"
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cls.RED = "\033[31m"
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cls.GREEN = "\033[32m"
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cls.YELLOW = "\033[33m"
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cls.BLUE = "\033[34m"
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cls.CYAN = "\033[36m"
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def warn(msg):
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print("%swarning:%s %s" % (C.YELLOW, C.RESET, msg), file=sys.stderr)
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def die(msg):
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print("%serror:%s %s" % (C.RED, C.RESET, msg), file=sys.stderr)
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sys.exit(1)
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# --------------------------------------------------------------------------- #
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# domain types
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# --------------------------------------------------------------------------- #
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class Replica(object):
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def __init__(self, name, node, health, has_data):
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self.name = name
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self.node = node # "" when Longhorn couldn't schedule it
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self.health = health
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self.has_data = has_data # holds a usable copy (healthyAt set, not failed)
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class Volume(object):
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def __init__(self, pvc_ns, pvc_name, lh_name, storage_class, robustness,
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state, desired_replicas, replicas=None, note=""):
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self.pvc_ns = pvc_ns
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self.pvc_name = pvc_name
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self.lh_name = lh_name
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self.storage_class = storage_class
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self.robustness = robustness
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self.state = state
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self.desired_replicas = desired_replicas
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self.replicas = replicas if replicas is not None else []
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self.note = note
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@property
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def data_nodes(self):
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"""Nodes holding a usable copy (healthyAt && !failedAt), regardless of
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whether the engine is currently running."""
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return set(r.node for r in self.replicas if r.has_data and r.node)
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@property
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def all_nodes(self):
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return set(r.node for r in self.replicas if r.node)
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@property
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def label(self):
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return "%s/%s" % (self.pvc_ns, self.pvc_name)
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class VM(object):
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def __init__(self, ns, name, status, node, pvcs):
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self.ns = ns
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self.name = name
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self.status = status
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self.node = node # node the VMI runs on (or None)
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self.pvcs = pvcs
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@property
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def running(self):
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return self.status == "Running"
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@property
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def label(self):
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return "%s/%s" % (self.ns, self.name)
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# --------------------------------------------------------------------------- #
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# building the model (identical semantics to disk-health-report.py)
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# --------------------------------------------------------------------------- #
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def classify_replica(rep):
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spec = rep.get("spec", {})
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status = rep.get("status", {})
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failed = bool(spec.get("failedAt"))
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healthy_at = bool(spec.get("healthyAt"))
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cur = status.get("currentState", "")
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has_data = healthy_at and not failed
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if failed:
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disp = "failed"
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elif cur == "running":
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disp = HEALTHY if healthy_at else "rebuilding"
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elif healthy_at:
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disp = "stopped"
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elif cur in ("stopped", "error"):
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disp = cur
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else:
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disp = cur or "unknown"
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return disp, has_data
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def vm_referenced_pvcs(vm_spec_volumes, ns):
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out = []
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for v in vm_spec_volumes or []:
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pvc = v.get("persistentVolumeClaim")
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if pvc and pvc.get("claimName"):
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out.append((ns, pvc["claimName"]))
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continue
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dv = v.get("dataVolume")
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if dv and dv.get("name"):
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out.append((ns, dv["name"]))
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return out
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def is_virt_launcher(pod):
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labels = pod.get("metadata", {}).get("labels", {}) or {}
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if labels.get("kubevirt.io") == "virt-launcher":
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return True
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for ref in pod.get("metadata", {}).get("ownerReferences", []) or []:
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if ref.get("kind") == "VirtualMachineInstance":
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return True
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return False
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def virt_launcher_vm_name(pod):
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for ref in pod.get("metadata", {}).get("ownerReferences", []) or []:
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if ref.get("kind") == "VirtualMachineInstance" and ref.get("name"):
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return ref["name"]
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return (pod.get("metadata", {}).get("labels", {}) or {}).get("vm.kubevirt.io/name", "")
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def build_volume(pvc_ns, pvc_name, pvc_index, pv_index, lh_vol_index, replicas_by_vol):
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pvc = pvc_index.get((pvc_ns, pvc_name))
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if pvc is None:
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return Volume(pvc_ns, pvc_name, None, "-", "-", "-", None, note="PVC not found")
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sc = pvc.get("spec", {}).get("storageClassName", "") or "-"
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pv_name = pvc.get("spec", {}).get("volumeName") or ""
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phase = pvc.get("status", {}).get("phase", "")
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if not pv_name:
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return Volume(pvc_ns, pvc_name, None, sc, "-", "-", None,
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note="unbound PVC (phase=%s)" % phase)
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pv = pv_index.get(pv_name)
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driver = ""
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if pv:
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driver = pv.get("spec", {}).get("csi", {}).get("driver", "")
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if pv and driver and driver != LONGHORN_CSI_DRIVER:
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node = _pv_pinned_node(pv)
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vol = Volume(pvc_ns, pvc_name, pv_name, sc, "-", "-", None,
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note="non-Longhorn (%s)" % driver)
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if node:
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vol.replicas.append(Replica(pv_name, node, HEALTHY, True))
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return vol
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lh = lh_vol_index.get(pv_name)
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if lh is None:
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return Volume(pvc_ns, pvc_name, pv_name, sc, "-", "-", None,
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note="no Longhorn volume CR")
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robustness = lh.get("status", {}).get("robustness", "unknown") or "unknown"
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state = lh.get("status", {}).get("state", "unknown") or "unknown"
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desired = lh.get("spec", {}).get("numberOfReplicas")
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vol = Volume(pvc_ns, pvc_name, pv_name, sc, robustness, state, desired)
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for rep in replicas_by_vol.get(pv_name, []):
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node = rep.get("spec", {}).get("nodeID", "") or ""
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disp, has_data = classify_replica(rep)
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vol.replicas.append(Replica(
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rep.get("metadata", {}).get("name", "?"), node, disp, has_data))
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vol.replicas.sort(key=lambda r: (r.node, r.name))
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return vol
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def _pv_pinned_node(pv):
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terms = (pv.get("spec", {}).get("nodeAffinity", {})
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.get("required", {}).get("nodeSelectorTerms", []))
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for term in terms:
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for expr in term.get("matchExpressions", []):
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if expr.get("key") == "kubernetes.io/hostname" and expr.get("values"):
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return expr["values"][0]
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return None
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def build_model(kc):
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"""Fetch + assemble the shared model. Returns (vms, volumes, vm_by_pvc,
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pods_by_pvc, nodes)."""
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vms_raw = kc.get("virtualmachines.kubevirt.io")
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vmis_raw = kc.get("virtualmachineinstances.kubevirt.io")
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pvcs_raw = kc.get("persistentvolumeclaims")
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pvs_raw = kc.get("persistentvolumes")
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pods_raw = kc.get("pods")
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lh_vols_raw = kc.get("volumes.longhorn.io", LONGHORN_NS)
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lh_reps_raw = kc.get("replicas.longhorn.io", LONGHORN_NS)
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pvc_index = dict(((p["metadata"]["namespace"], p["metadata"]["name"]), p) for p in pvcs_raw)
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pv_index = dict((p["metadata"]["name"], p) for p in pvs_raw)
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lh_vol_index = dict((v["metadata"]["name"], v) for v in lh_vols_raw)
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replicas_by_vol = defaultdict(list)
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for rep in lh_reps_raw:
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vn = rep.get("spec", {}).get("volumeName")
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if vn:
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replicas_by_vol[vn].append(rep)
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vmi_index = dict(((v["metadata"]["namespace"], v["metadata"]["name"]), v) for v in vmis_raw)
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vms = []
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for raw in vms_raw:
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ns = raw["metadata"]["namespace"]
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name = raw["metadata"]["name"]
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status = raw.get("status", {}).get("printableStatus", "") or "Unknown"
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spec_vols = (raw.get("spec", {}).get("template", {})
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.get("spec", {}).get("volumes", []))
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pvcs = vm_referenced_pvcs(spec_vols, ns)
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node = None
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vmi = vmi_index.get((ns, name))
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if vmi:
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node = vmi.get("status", {}).get("nodeName")
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for extra in vm_referenced_pvcs(vmi.get("spec", {}).get("volumes", []), ns):
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if extra not in pvcs:
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pvcs.append(extra)
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vms.append(VM(ns, name, status, node, pvcs))
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vms.sort(key=lambda v: (v.ns, v.name))
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vm_by_key = dict(((vm.ns, vm.name), vm) for vm in vms)
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# A running VM's virt-launcher pod mounts everything the VM uses, including
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# the persistent-state/EFI-vars and hot-plug PVCs not in the VM spec.
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pods_by_pvc = defaultdict(list)
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for pod in pods_raw:
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pns = pod["metadata"]["namespace"]
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pnode = pod.get("spec", {}).get("nodeName", "") or "?"
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pname = pod["metadata"]["name"]
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claims = [v["persistentVolumeClaim"]["claimName"]
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for v in pod.get("spec", {}).get("volumes", []) or []
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if v.get("persistentVolumeClaim", {}).get("claimName")]
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if is_virt_launcher(pod):
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vm = vm_by_key.get((pns, virt_launcher_vm_name(pod)))
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if vm is not None:
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for c in claims:
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if (pns, c) not in vm.pvcs:
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vm.pvcs.append((pns, c))
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continue
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for c in claims:
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pods_by_pvc[(pns, c)].append((pname, pnode))
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vm_pvc_set = set(p for vm in vms for p in vm.pvcs)
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all_pvc_keys = set(pvc_index.keys()) | vm_pvc_set
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volumes = dict((k, build_volume(k[0], k[1], pvc_index, pv_index,
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lh_vol_index, replicas_by_vol)) for k in all_pvc_keys)
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vm_by_pvc = {}
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for vm in vms:
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for key in vm.pvcs:
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vm_by_pvc[key] = vm
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nodes = sorted(set(r.node for v in volumes.values() for r in v.replicas if r.node))
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return vms, volumes, vm_by_pvc, pods_by_pvc, nodes
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# --------------------------------------------------------------------------- #
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# node plan
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# --------------------------------------------------------------------------- #
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def plan_for_node(node, vms, volumes, vm_by_pvc, pods_by_pvc):
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"""Return the per-node plan dict for `node`."""
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# Volumes whose ONLY usable copy is on this node, grouped by owner.
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vm_only = defaultdict(list) # VM -> [Volume only here]
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pod_only = [] # [(Volume, [(pod, node), ...])]
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detached_only = [] # [Volume]
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for key, vol in volumes.items():
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if not vol.replicas or vol.data_nodes != set([node]):
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continue
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owner = vm_by_pvc.get(key)
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if owner is not None:
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vm_only[owner].append(vol)
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elif pods_by_pvc.get(key):
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pod_only.append((vol, pods_by_pvc[key]))
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else:
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detached_only.append(vol)
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running_here = [vm for vm in vms if vm.node == node]
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# VMs running here whose data is all safe elsewhere (not already in vm_only).
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running_safe = [vm for vm in running_here if vm not in vm_only]
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return {
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"vm_only": vm_only, # data-loss risk
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"running_safe": running_safe, # compute-only risk
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"pod_only": pod_only,
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"detached_only": detached_only,
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"runs": len(running_here),
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}
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def print_report(nodes, vms, volumes, vm_by_pvc, pods_by_pvc):
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print("%s=== NODE SHUTDOWN / MAINTENANCE PLAN ===%s" % (C.BOLD, C.RESET))
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if not nodes:
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print(" no replica-bearing nodes found (no Longhorn volumes?).\n")
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return
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for node in nodes:
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p = plan_for_node(node, vms, volumes, vm_by_pvc, pods_by_pvc)
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vm_only, running_safe = p["vm_only"], p["running_safe"]
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pod_only, detached_only = p["pod_only"], p["detached_only"]
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header = "\n%sNODE %s%s %s(runs %d VM%s)%s" % (
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C.BOLD, node, C.RESET, C.DIM, p["runs"], "" if p["runs"] == 1 else "s", C.RESET)
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print(header)
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if not vm_only and not running_safe and not pod_only and not detached_only:
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print(" %sSAFE to take down%s: nothing lives only here and no VMs run here."
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% (C.GREEN, C.RESET))
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continue
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running_risk = [vm for vm in vm_only if vm.running]
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stopped_risk = [vm for vm in vm_only if not vm.running]
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def only_here(vm):
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return ", ".join(v.pvc_name for v in sorted(vm_only[vm], key=lambda v: v.pvc_name))
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if running_risk:
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print(" %sShut down cleanly FIRST -- running VMs whose only data copy is here:%s"
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% (C.RED, C.RESET))
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for vm in sorted(running_risk, key=lambda v: v.label):
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run = "runs here" if vm.node == node else ("runs on %s" % vm.node)
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print(" - %s%s%s [%s] (%s) only-here: %s"
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% (C.BOLD, vm.label, C.RESET, colour_status(vm.status), run, only_here(vm)))
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if running_safe:
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print(" %sRunning on this node -- stop or migrate (data is safe elsewhere):%s"
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% (C.YELLOW, C.RESET))
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for vm in sorted(running_safe, key=lambda v: v.label):
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print(" - %s [%s]" % (vm.label, colour_status(vm.status)))
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if stopped_risk or pod_only or detached_only:
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print(" %sOnly here, no shutdown needed -- offline during maintenance, "
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"lost if removed permanently:%s" % (C.DIM, C.RESET))
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for vm in sorted(stopped_risk, key=lambda v: v.label):
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print(" - VM %s [%s] only-here: %s"
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% (vm.label, colour_status(vm.status), only_here(vm)))
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for vol, consumers in sorted(pod_only, key=lambda x: x[0].label):
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who = ", ".join("%s" % n for n, _ in consumers)
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print(" - %s (used by pod: %s)" % (vol.label, who))
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for vol in sorted(detached_only, key=lambda v: v.label):
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print(" - %s (detached)" % vol.label)
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print()
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def colour_status(status):
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if status == "Running":
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return "%s%s%s" % (C.GREEN, status, C.RESET)
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if status in ("Stopped", "Paused"):
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return "%s%s%s" % (C.YELLOW, status, C.RESET)
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return "%s%s%s" % (C.CYAN, status, C.RESET)
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def emit_json(nodes, vms, volumes, vm_by_pvc, pods_by_pvc):
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out = {}
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for node in nodes:
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p = plan_for_node(node, vms, volumes, vm_by_pvc, pods_by_pvc)
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vm_only = p["vm_only"]
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running_risk = [vm for vm in vm_only if vm.running]
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|
stopped_risk = [vm for vm in vm_only if not vm.running]
|
|
out[node] = {
|
|
"runs_vms": p["runs"],
|
|
"shut_down_first": [
|
|
{"vm": vm.label, "status": vm.status, "runs_on": vm.node,
|
|
"volumes_only_here": sorted(v.pvc_name for v in vm_only[vm])}
|
|
for vm in sorted(running_risk, key=lambda v: v.label)
|
|
],
|
|
"running_here_data_safe": [
|
|
{"vm": vm.label, "status": vm.status}
|
|
for vm in sorted(p["running_safe"], key=lambda v: v.label)
|
|
],
|
|
"only_here_no_shutdown": (
|
|
[{"kind": "stopped-vm", "name": vm.label,
|
|
"volumes_only_here": sorted(v.pvc_name for v in vm_only[vm])}
|
|
for vm in sorted(stopped_risk, key=lambda v: v.label)]
|
|
+ [{"kind": "pod", "name": vol.label, "consumer_pods": [n for n, _ in cons]}
|
|
for vol, cons in p["pod_only"]]
|
|
+ [{"kind": "detached", "name": vol.label} for vol in p["detached_only"]]
|
|
),
|
|
"safe": not (vm_only or p["running_safe"] or p["pod_only"] or p["detached_only"]),
|
|
}
|
|
print(json.dumps(out, indent=2))
|
|
|
|
|
|
def main():
|
|
ap = argparse.ArgumentParser(
|
|
description="Per-node maintenance plan: what lives only on a node and "
|
|
"which VMs to shut down before taking it down.")
|
|
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("--node", help="report only this node (default: all nodes)")
|
|
ap.add_argument("--json", action="store_true", dest="as_json",
|
|
help="emit the structured plan as JSON")
|
|
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)
|
|
vms, volumes, vm_by_pvc, pods_by_pvc, nodes = build_model(kc)
|
|
|
|
if args.node:
|
|
if args.node not in nodes:
|
|
die("node %r not found; known nodes: %s" % (args.node, ", ".join(nodes) or "(none)"))
|
|
nodes = [args.node]
|
|
|
|
if args.as_json:
|
|
emit_json(nodes, vms, volumes, vm_by_pvc, pods_by_pvc)
|
|
else:
|
|
print_report(nodes, vms, volumes, vm_by_pvc, pods_by_pvc)
|
|
|
|
|
|
if __name__ == "__main__":
|
|
main()
|