Beginner 8 min
The pods that won't stay up
A hands-on Kubernetes debugging lab using simulated kubectl commands and configuration changes.
# Kubernetes# Debugging# Deployments
Labs
Small production failures. Concrete actions. Use the terminal to investigate each incident, apply a safe change, and prove that it worked.
Hands-on practice
Choose an incident
Beginner 7 min
The service with no endpoints
A hands-on Kubernetes networking lab for debugging a Service selector that no longer matches its Pods.
# Kubernetes# Networking# Services
Beginner 8 min
A safe tunnel to PostgreSQL
Reach a private PostgreSQL Service with kubectl port-forward, without exposing the database publicly.
# Databases# PostgreSQL# Kubernetes# Networking
Intermediate 10 min
The ALB with healthy instances and no traffic
Diagnose an AWS Application Load Balancer whose target health check still uses a removed path.
# AWS# Networking# ALB# Terraform
Intermediate 10 min
The private hostname pointing to yesterday
Follow DNS evidence from resolver to route and correct a stale private record after an ingress migration.
# Networking# DNS# AWS# Troubleshooting
Intermediate 11 min
The role that can read S3 but not the secret
Trace an AWS AccessDenied across S3 and KMS, then grant the workload only the missing decrypt permission.
# AWS# IAM# KMS# Security
Advanced 12 min
PostgreSQL has no connections left
Find an oversized application pool and idle transactions before they turn connection pressure into an outage.
# PostgreSQL# Databases# Connection pools# Reliability
Advanced 12 min
The Terraform lock nobody owns
Investigate a remote state lock, prove that no run is active, and remove only the orphaned lock.
# Terraform# State# AWS# Operations
Advanced 14 min
The query that scans twelve million orders
Read an execution plan and add one composite index that matches the production query's filter and sort.
# MySQL# Databases# Indexes# Performance
Advanced 15 min
The policy that allows the API but blocks its names
Debug a default-deny Kubernetes egress policy that permits the database IP path but silently blocks DNS.
# Kubernetes# Networking# NetworkPolicy# DNS