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 a DevOps/SRE/DevSecOps/Cloud Expert passionate about sharing knowledge and experiences. I have worked at Cotocus. I share tech blog at DevOps School, travel stories at Holiday Landmark, stock market tips at Stocks Mantra, health and fitness guidance at My Medic Plus, product reviews at TrueReviewNow , and SEO strategies at Wizbrand.

Do you want to learn Quantum Computing?

Please find my social handles as below;

Rajesh Kumar Personal Website
Rajesh Kumar at YOUTUBE
Rajesh Kumar at INSTAGRAM
Rajesh Kumar at X
Rajesh Kumar at FACEBOOK
Rajesh Kumar at LINKEDIN
Rajesh Kumar at WIZBRAND