HTTP probe configuration in Kubernetes - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to set the HTTP probe path to "/healthz".

Kubernetes

livenessProbe:
  httpGet:
    path: "[1]"
    port: 8080

Drag options to blanks, or click blank then click option'

A/check

B/status

C/healthz

D/ready

Attempts:

3 left

💡 Hint

Common Mistakes

Using a path without a leading slash.

Choosing a path that does not exist in the application.

The HTTP probe path should be set to /healthz to check the health endpoint.

2fill in blank

medium

Complete the code to set the HTTP probe port to 8080.

Kubernetes

readinessProbe:
  httpGet:
    path: "/ready"
    port: [1]

Drag options to blanks, or click blank then click option'

A8080

B3000

C443

D80

Attempts:

3 left

💡 Hint

Common Mistakes

Using the wrong port number that the application does not listen on.

Confusing HTTP and HTTPS ports.

The HTTP probe port should match the application's listening port, which is 8080 here.

3fill in blank

hard

Fix the error in the HTTP probe configuration by completing the missing field.

Kubernetes

livenessProbe:
  httpGet:
    path: "/health"
    port: 8080
  [1]: 5

Drag options to blanks, or click blank then click option'

AtimeoutSeconds

BfailureThreshold

CperiodSeconds

DinitialDelaySeconds

Attempts:

3 left

💡 Hint

Common Mistakes

Using timeoutSeconds instead of initialDelaySeconds for delay.

Omitting the delay causing probe failures on startup.

The initialDelaySeconds field specifies how long to wait before starting the probe.

4fill in blank

hard

Fill both blanks to configure the readiness probe with a 3-second timeout and a 10-second period.

Kubernetes

readinessProbe:
  httpGet:
    path: "/ready"
    port: 8080
  [1]: 3
  [2]: 10

Drag options to blanks, or click blank then click option'

AtimeoutSeconds

BinitialDelaySeconds

CperiodSeconds

DfailureThreshold

Attempts:

3 left

💡 Hint

Common Mistakes

Swapping timeoutSeconds and periodSeconds values.

Using initialDelaySeconds instead of timeoutSeconds.

timeoutSeconds sets how long to wait for a response. periodSeconds sets how often to run the probe.

5fill in blank

hard

Fill all three blanks to configure a liveness probe with a 5-second initial delay, 2-second timeout, and 15-second period.

Kubernetes

livenessProbe:
  httpGet:
    path: "/healthz"
    port: 8080
  [1]: 5
  [2]: 2
  [3]: 15

Drag options to blanks, or click blank then click option'

AinitialDelaySeconds

BtimeoutSeconds

CperiodSeconds

DfailureThreshold

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing up the timing fields.

Omitting initialDelaySeconds causing early probe failures.

initialDelaySeconds waits before starting probes, timeoutSeconds sets response wait time, and periodSeconds sets probe frequency.

Practice

1. What is the main purpose of an HTTP probe in Kubernetes?

easy

A. To deploy new versions of the application automatically

B. To store application logs for debugging

C. To check if the application is running and responding to HTTP requests

D. To manage network traffic between pods

Solution

1. Step 1: Understand the role of HTTP probes

   HTTP probes send HTTP requests to the app to check if it is alive and ready.

2. Step 2: Identify the correct purpose

   Only To check if the application is running and responding to HTTP requests describes checking app health via HTTP requests.

3. Final Answer:

   To check if the application is running and responding to HTTP requests -> Option C

4. Quick Check:

   HTTP probe purpose = health check [OK]

Hint: HTTP probes test app health by sending HTTP requests [OK]

Common Mistakes:

• Confusing probes with deployment or logging
• Thinking probes manage network traffic
• Assuming probes store logs

2. Which of the following is the correct syntax to define an HTTP liveness probe in a Kubernetes pod spec?

easy

A. livenessProbe:
exec:
command: ["curl", "/healthz"]
initialDelaySeconds: 5
periodSeconds: 10

B. livenessProbe:
httpGet:
path: /healthz
port: 8080
initialDelaySeconds: 5
periodSeconds: 10

C. livenessProbe:
tcpSocket:
port: 8080
initialDelaySeconds: 5
periodSeconds: 10

D. livenessProbe:
httpGet:
url: http://localhost:8080/healthz
initialDelaySeconds: 5
periodSeconds: 10

Solution

1. Step 1: Review HTTP probe syntax

   The correct HTTP probe uses httpGet with path and port keys.

2. Step 2: Identify the correct YAML structure

   livenessProbe: httpGet: path: /healthz port: 8080 initialDelaySeconds: 5 periodSeconds: 10 correctly uses httpGet with path and port. livenessProbe: httpGet: url: http://localhost:8080/healthz initialDelaySeconds: 5 periodSeconds: 10 is invalid because url is not a valid key.

3. Final Answer:

   Correct HTTP liveness probe syntax with httpGet, path, and port -> Option B

4. Quick Check:

   httpGet uses path and port keys [OK]

Hint: Use httpGet with path and port, not url [OK]

Common Mistakes:

• Using 'url' instead of 'path' in httpGet
• Confusing exec or tcpSocket probes with httpGet
• Wrong indentation or missing keys

3. Given this probe configuration snippet in a pod spec:

livenessProbe:
  httpGet:
    path: /status
    port: 8080
  initialDelaySeconds: 10
  periodSeconds: 5

What will Kubernetes do after the pod starts?

medium

A. Send an HTTP GET to /status only once after 10 seconds

B. Send an HTTP GET to /status immediately, then every 10 seconds

C. Wait 5 seconds, then send an HTTP GET to /status every 10 seconds

D. Wait 10 seconds, then send an HTTP GET to /status every 5 seconds

Solution

1. Step 1: Understand initialDelaySeconds

   This value tells Kubernetes to wait 10 seconds after pod start before first probe.

2. Step 2: Understand periodSeconds

   This value sets the interval between probes, here every 5 seconds.

3. Final Answer:

   Wait 10 seconds, then send an HTTP GET to /status every 5 seconds -> Option D

4. Quick Check:

   initialDelaySeconds = wait, periodSeconds = repeat interval [OK]

Hint: initialDelaySeconds = wait before first probe, periodSeconds = probe interval [OK]

Common Mistakes:

• Confusing initialDelaySeconds with periodSeconds
• Assuming immediate probe on pod start
• Mixing up timing values

4. You configured this HTTP readiness probe:

readinessProbe:
  httpGet:
    path: /ready
    port: 80
  initialDelaySeconds: 5
  periodSeconds: 10
  timeoutSeconds: 2

But Kubernetes marks the pod as not ready even though the app is healthy. What is the likely problem?

medium

A. The probe path /ready is incorrect or not handled by the app

B. initialDelaySeconds is too high, delaying readiness

C. timeoutSeconds is too long, causing probe to fail

D. periodSeconds is too short, causing probe overload

Solution

1. Step 1: Check probe path correctness

   If the app does not respond correctly to /ready, probe fails and pod is not ready.

2. Step 2: Evaluate timing parameters

   initialDelaySeconds of 5 is reasonable; timeoutSeconds of 2 is short but typical; periodSeconds of 10 is normal.

3. Final Answer:

   The probe path /ready is incorrect or not handled by the app -> Option A

4. Quick Check:

   Probe path must match app endpoint [OK]

Hint: Check if probe path matches app endpoint exactly [OK]

Common Mistakes:

• Ignoring probe path correctness
• Changing timing values unnecessarily
• Assuming timeoutSeconds causes readiness failure

5. You want to configure a Kubernetes HTTP readiness probe that waits 15 seconds after container start, then checks the path /health every 3 seconds, but fails the pod if no response within 1 second. Which is the correct probe configuration snippet?

hard

A. readinessProbe:
httpGet:
path: /health
port: 8080
initialDelaySeconds: 15
periodSeconds: 3
timeoutSeconds: 1

B. readinessProbe:
httpGet:
path: /health
port: 8080
initialDelaySeconds: 3
periodSeconds: 15
timeoutSeconds: 1

C. readinessProbe:
httpGet:
path: /health
port: 8080
initialDelaySeconds: 15
periodSeconds: 1
timeoutSeconds: 3

D. readinessProbe:
httpGet:
path: /health
port: 8080
initialDelaySeconds: 1
periodSeconds: 15
timeoutSeconds: 3

Solution

1. Step 1: Match initialDelaySeconds to 15 seconds

   The probe must wait 15 seconds before first check, so initialDelaySeconds: 15.

2. Step 2: Set periodSeconds to 3 seconds and timeoutSeconds to 1 second

   Checks happen every 3 seconds, and timeout is 1 second as required.

3. Final Answer:

   Correct probe with initialDelaySeconds 15, periodSeconds 3, timeoutSeconds 1 -> Option A

4. Quick Check:

   initialDelay=15, period=3, timeout=1 matches requirements [OK]

Hint: Match timing values exactly to requirements [OK]

Common Mistakes:

• Swapping initialDelaySeconds and periodSeconds
• Setting timeoutSeconds longer than periodSeconds
• Using wrong path or port