Part 3 Cumulative Quiz: Application Observability and Maintenance

Time Limit: 20 minutes (simulating exam pressure)

Passing Score: 80% (8/10 questions)

This quiz tests your mastery of:

• Application probes (liveness, readiness, startup)
• Container logging
• Debugging techniques
• Monitoring with kubectl top
• API deprecations

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Instructions

1. Try each question without looking at answers
2. Time yourself—speed matters for CKAD
3. Use only kubectl and kubernetes.io/docs
4. Check answers after completing all questions

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Questions

Question 1: Liveness Probe

[2 minutes]

Create a Pod named health-check with nginx that:

• Has an HTTP liveness probe on path / port 80
• Checks every 10 seconds
• Waits 5 seconds before first check

Answer

cat << 'EOF' | k apply -f -
apiVersion: v1
kind: Pod
metadata:
  name: health-check
spec:
  containers:
  - name: nginx
    image: nginx
    livenessProbe:
      httpGet:
        path: /
        port: 80
      initialDelaySeconds: 5
      periodSeconds: 10
EOF

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Question 2: Readiness Probe

[2 minutes]

A pod webapp has a readiness probe configured, but it’s never becoming Ready. How do you investigate?

Answer

# Check pod status
k get pod webapp

# Describe to see probe config and events
k describe pod webapp | grep -A10 Readiness
k describe pod webapp | tail -20

# Check endpoints (pod should not be in endpoints if not ready)
k get endpoints

# Check if probe path/port is correct
k exec webapp -- curl -s localhost:8080/ready

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Question 3: Combined Probes

[3 minutes]

Create a Deployment named api-server with 2 replicas that:

• Uses image nginx
• Has startup probe: HTTP GET / port 80, failure threshold 30, period 10s
• Has liveness probe: HTTP GET / port 80, period 10s
• Has readiness probe: HTTP GET / port 80, period 5s

Answer

cat << 'EOF' | k apply -f -
apiVersion: apps/v1
kind: Deployment
metadata:
  name: api-server
spec:
  replicas: 2
  selector:
    matchLabels:
      app: api-server
  template:
    metadata:
      labels:
        app: api-server
    spec:
      containers:
      - name: nginx
        image: nginx
        ports:
        - containerPort: 80
        startupProbe:
          httpGet:
            path: /
            port: 80
          failureThreshold: 30
          periodSeconds: 10
        livenessProbe:
          httpGet:
            path: /
            port: 80
          periodSeconds: 10
        readinessProbe:
          httpGet:
            path: /
            port: 80
          periodSeconds: 5
EOF

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Question 4: Container Logs

[1 minute]

Get the last 50 lines of logs from the previous instance of container app in pod crashing-pod.

Answer

k logs crashing-pod -c app --previous --tail=50

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Question 5: Multi-Container Logs

[2 minutes]

A pod multi-app has containers named frontend and backend. Stream logs from both containers.

Answer

# All containers at once
k logs multi-app --all-containers -f

# Or separately
k logs multi-app -c frontend -f &
k logs multi-app -c backend -f

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Question 6: Debug CrashLoopBackOff

[2 minutes]

A pod is in CrashLoopBackOff. What’s your debugging workflow?

Answer

# 1. Check current status
k get pod crashing-pod

# 2. Get logs from crashed instance
k logs crashing-pod --previous

# 3. Check exit code and events
k describe pod crashing-pod | grep -A5 "Last State"
k describe pod crashing-pod | tail -15

# 4. Check if liveness probe is too aggressive
k describe pod crashing-pod | grep -A5 Liveness

# 5. If needed, check container config
k get pod crashing-pod -o yaml | grep -A20 containers

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Question 7: Service Debug

[2 minutes]

A Service web-svc has no endpoints. How do you find and fix the problem?

Answer

# Check endpoints
k get endpoints web-svc

# Get service selector
k describe svc web-svc | grep Selector

# Get pod labels
k get pods --show-labels

# If labels don't match, fix the service or pods
# Example: Fix service selector
k patch svc web-svc -p '{"spec":{"selector":{"app":"correct-label"}}}'

# Verify
k get endpoints web-svc

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Question 8: Resource Monitoring

[2 minutes]

Find the top 5 pods by memory usage across all namespaces.

Answer

k top pods -A --sort-by=memory | head -6

(head -6 because first line is header)

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Question 9: API Version Lookup

[1 minute]

What are the current API versions for these resources?

• Ingress
• CronJob
• NetworkPolicy

Answer

networking.k8s.io/v1

# Quick lookup
k explain ingress | grep VERSION
k explain cronjob | grep VERSION
# batch/v1

k explain networkpolicy | grep VERSION
# networking.k8s.io/v1

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Question 10: Exec Probe

[2 minutes]

Create a Pod named file-check with busybox that:

• Runs sleep 3600
• Has a liveness probe that checks if file /tmp/healthy exists
• Probe runs every 5 seconds, initial delay 10 seconds

Answer

cat << 'EOF' | k apply -f -
apiVersion: v1
kind: Pod
metadata:
  name: file-check
spec:
  containers:
  - name: busybox
    image: busybox
    command: ['sh', '-c', 'touch /tmp/healthy && sleep 3600']
    livenessProbe:
      exec:
        command:
        - cat
        - /tmp/healthy
      initialDelaySeconds: 10
      periodSeconds: 5
EOF

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Scoring

Questions Correct	Score	Status
10/10	100%	Excellent - Ready for exam
8-9/10	80-90%	Good - Minor review needed
6-7/10	60-70%	Review weak areas
<6/10	<60%	Revisit Part 3 modules

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Cleanup

k delete pod health-check file-check 2>/dev/null
k delete deploy api-server 2>/dev/null

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Key Takeaways

If you scored less than 80%, review these areas:

• Missed Q1-3: Review Module 3.1 (Probes) - probe types and configuration
• Missed Q4-5: Review Module 3.2 (Logging) - log commands and multi-container
• Missed Q6-7: Review Module 3.3 (Debugging) - systematic troubleshooting
• Missed Q8: Review Module 3.4 (Monitoring) - kubectl top commands
• Missed Q9: Review Module 3.5 (API Deprecations) - current versions
• Missed Q10: Review Module 3.1 (Probes) - exec probes

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Next Part

Part 4: Application Environment, Configuration and Security - ConfigMaps, Secrets, SecurityContexts, and more.