diag-k8s-node-pressure

K8s Node Pressure Full-Chain Diagnostics

用途

当节点出现 NotReady、Pod 被驱逐、或监控报节点资源告警时触发。

输入

• kubectl 上下文、目标节点名称（可选，默认排查所有）

输出

• 节点资源压力报告 + 缓解建议

诊断步骤

Step 1: 节点状态总览

kubectl get nodes -o wide
kubectl describe node {node_name}
# 关注 Conditions: MemoryPressure / DiskPressure / PIDPressure / Ready

Step 2: 资源用量

kubectl top nodes
kubectl top pods --all-namespaces --sort-by=memory | head -20
kubectl top pods --all-namespaces --sort-by=cpu | head -20

Step 3: 驱逐事件

# 最近被驱逐的 Pod
kubectl get events --all-namespaces --field-selector reason=Evicted --sort-by='.lastTimestamp' | tail -20

# 节点上的驱逐历史
kubectl get events --field-selector involvedObject.name={node_name} | grep -i evict

Step 4: Allocatable vs Allocated

kubectl describe node {node_name} | grep -A 20 "Allocated resources"
# 关注 CPU/ memory requests 占 Allocatable 的百分比

Step 5: 系统级排查

# 在目标节点上（SSH 或通过 kubectl debug）
df -h                          # 磁盘使用
free -h                        # 内存使用
ps aux --sort=-%mem | head -10 # 高内存进程
dmesg | grep -i oom            # OOM killer
journalctl -u kubelet --since "1 hour ago" | tail -50

输出模板

K8s Node Pressure Analysis Report
════════════════════════════════════════
Cluster: {context}
Node:    {node_name}
Time:    {timestamp}

Node Conditions
  Ready:            {ready}
  MemoryPressure:   {mem_pressure}
  DiskPressure:     {disk_pressure}
  PIDPressure:      {pid_pressure}

Resource Usage
  CPU:     {cpu_used}/{cpu_allocatable} ({cpu_pct}%)
  Memory:  {mem_used}/{mem_allocatable} ({mem_pct}%)
  Disk:    {disk_used}/{disk_total} ({disk_pct}%)
  Pods:    {pod_count}/{pod_max}

Top Consumers (by memory)
  | Pod | Namespace | Memory | CPU |
  |-----|-----------|--------|-----|
  | {pod_1} | {ns_1} | {mem_1} | {cpu_1} |

Evicted Pods (last 10)
  {evicted_pod_1} at {time_1}: {reason_1}

Allocated Resources
  CPU Requests:    {cpu_req_pct}% of allocatable
  Memory Requests: {mem_req_pct}% of allocatable

Root Cause: {root_cause}

Recommendations
  1. {immediate_action}
  2. {scaling_action}
  3. {long_term_fix}