Error #24 - ConfigMap NotFound Troubleshoot and Fix

IN TODAY'S EDIT

USE CASE

ConfigMap NotFound - Troubleshoot and Fix

🚨 Kubernetes Error: ConfigMap NotFound 🚨

Are you facing a ConfigMap NotFound error in Kubernetes? 🤔 This error usually occurs when a Pod or Deployment references a non-existent ConfigMap. Let’s break down the causes, troubleshooting steps, and preventive measures to avoid such issues in the future.

Causes of ConfigMap NotFound Error

1️⃣ ConfigMap Doesn’t Exist – The referenced ConfigMap hasn’t been created.
2️⃣ Incorrect Namespace – The ConfigMap is in a different namespace than your workload.
3️⃣ Typo in ConfigMap Name – A mismatch in the name when defining it in a Pod/Deployment.
4️⃣ ConfigMap Deleted – Someone accidentally deleted the ConfigMap.
5️⃣ Race Condition – The Pod starts before the ConfigMap is created.

🛠 Troubleshooting Steps

✅ Check if ConfigMap Exists

kubectl get configmap -n <namespace>

If it’s missing, create it using:

kubectl create configmap <configmap-name> --from-literal=key=value -n <namespace>

✅ Verify Namespace
Ensure the Pod and ConfigMap are in the same namespace:

kubectl get configmap -n <namespace> kubectl get pods -n <namespace>

✅ Check ConfigMap Name in Deployment
Inspect the Deployment/Pod YAML and ensure the correct reference:

volumes: - name: config-volume configMap: name: <configmap-name> # Ensure this matches the actual ConfigMap name

✅ Check Events and Logs

kubectl describe pod <pod-name> -n <namespace> kubectl logs <pod-name> -n <namespace>

✅ Recreate the Pod
If everything looks correct but the Pod still fails, restart it:

kubectl delete pod <pod-name> -n <namespace>

🚀 Preventive Measures

🔹 Always create ConfigMaps before referencing them in Deployments
🔹 Use Namespace-aware references (metadata.namespace)
🔹 Implement Admission Controllers or Validating Webhooks to check ConfigMap existence before Pod creation
🔹 Use initContainers to wait for ConfigMap availability
🔹 Monitor ConfigMaps with automated alerts (Prometheus/Grafana)

By following these steps, you can eliminate ConfigMap NotFound errors and ensure smooth Kubernetes deployments.