Below is a complete, production-grade list of all common reasons why a Kubernetes pod stays in Pending state, along with detailed solutions, commands, and how to verify and fix each issue.

🔍 How to Start Investigating

kubectl describe pod <pod-name>
Code language: HTML, XML (xml)

Focus on the Events: section — it will reveal why the pod is stuck.

🔁 Common Reasons and Solutions

🧪 Bonus: Best Commands for Troubleshooting

# Check events on the pod
kubectl describe pod <pod-name>

# Check node pod limits
kubectl describe node <node-name> | grep -A10 Allocatable

# List all pods on a node
kubectl get pods --all-namespaces -o wide | grep <node-name>

# PVC status
kubectl get pvc

# CNI status
kubectl get pods -n kube-system | grep -E 'cni|calico|flannel'

# Resource quotas
kubectl describe resourcequota
kubectl describe limitrange

# Get pod spec with scheduler/affinity/tolerations
kubectl get pod <pod-name> -o yaml
Code language: PHP (php)

🧭 How to Fix Pending in General

1. Start with kubectl describe pod
2. If it says:
   • Too many pods → Increase maxPods or add nodes
   • Insufficient cpu/memory → Reduce resource requests or free up node
   • Taint → Add toleration or remove taint
   • PVC pending → Fix volume
   • No message → Check CNI/DNS

Here is a Bash script that checks for the 20 most common reasons why Kubernetes pods are stuck in Pending state.

✅ It loops over all Pending pods and checks taints, resources, PVCs, tolerations, affinity, maxPods, etc.

📦 You can copy, save as check-pending-pods.sh, and run on your control-plane/master node.

✅ check-pending-pods.sh

#!/bin/bash

echo "=========================="
echo "🔍 Checking Pending Pods..."
echo "=========================="

PENDING_PODS=$(kubectl get pods --all-namespaces --field-selector=status.phase=Pending -o jsonpath='{range .items[*]}{.metadata.namespace}{" "}{.metadata.name}{"\n"}{end}')

if [ -z "$PENDING_PODS" ]; then
  echo "✅ No pending pods found."
  exit 0
fi

echo "$PENDING_PODS" | while read namespace pod; do
  echo ""
  echo "🔍 Analyzing pod: $pod in namespace: $namespace"
  echo "------------------------------------------------"

  # Describe pod
  kubectl describe pod $pod -n $namespace > /tmp/pod_desc.txt

  # 1. Check for failed scheduling
  grep -i "FailedScheduling" /tmp/pod_desc.txt

  # 2. Check node selectors
  echo "🧪 NodeSelector:"
  grep -A2 "Node-Selectors" /tmp/pod_desc.txt

  # 3. Check tolerations
  echo "🧪 Tolerations:"
  grep -A5 "Tolerations:" /tmp/pod_desc.txt

  # 4. Check affinity
  echo "🧪 Affinity:"
  kubectl get pod $pod -n $namespace -o jsonpath='{.spec.affinity}' || echo "None"

  # 5. Check resource requests
  echo "🧪 Resource Requests:"
  kubectl get pod $pod -n $namespace -o jsonpath='{range .spec.containers[*]}{.name}{" => CPU: "}{.resources.requests.cpu}{" | MEM: "}{.resources.requests.memory}{"\n"}{end}'

  # 6. Check PVCs
  echo "🧪 PVCs:"
  PVCs=$(kubectl get pod $pod -n $namespace -o jsonpath='{.spec.volumes[*].persistentVolumeClaim.claimName}')
  for pvc in $PVCs; do
    echo "  🔄 PVC: $pvc => Status: $(kubectl get pvc $pvc -n $namespace -o jsonpath='{.status.phase}')"
  done

  # 7. Check scheduler
  echo "🧪 Scheduler:"
  kubectl get pod $pod -n $namespace -o jsonpath='{.spec.schedulerName}'; echo

  echo ""
done

echo "==============================="
echo "🔍 Checking Node Conditions..."
echo "==============================="

for node in $(kubectl get nodes -o name); do
  echo ""
  echo "Node: $node"
  echo "-----------"

  echo "🧪 Taints:"
  kubectl describe $node | grep Taint || echo "No taints"

  echo "🧪 Allocatable Resources:"
  kubectl describe $node | grep -A10 "Allocatable"

  echo "🧪 Max Pods Limit:"
  kubectl describe $node | grep -A10 Allocatable | grep "pods"
  
  echo "🧪 Running Pods Count:"
  nodeName=$(basename $node)
  kubectl get pods --all-namespaces -o wide | grep $nodeName | wc -l
done

echo ""
echo "✅ Done checking all pending pod conditions!"
Code language: PHP (php)

🧪 How to Use

1. Save the script:

nano check-pending-pods.sh
# Paste the code
chmod +x check-pending-pods.sh
Code language: CSS (css)

2. Run the script:

./check-pending-pods.sh

✅ What it Checks

• Pod scheduling failures
• Node selectors
• Tolerations
• Affinity/anti-affinity
• CPU/Memory resource requests
• PVC binding status
• Scheduler used
• Taints on nodes
• Allocatable and used pod count
• Max pod limits

Rajesh Kumar

I’m Rajesh Kumar, a DevOps, SRE, DevSecOps, Cloud, and Platform Engineering expert passionate about sharing practical knowledge, real-world experiences, and industry best practices. I have worked at Cotocus and regularly write about technology, travel, investing, health, product reviews, and digital marketing through my various platforms.

I publish technical articles at DevOps School, travel stories at Holiday Landmark, stock market insights at Stocks Mantra, health and fitness guidance at My Medic Plus, product reviews at TrueReviewNow, and SEO and digital marketing strategies at Wizbrand.