The correct answer is to create the subnet with the primary range 10.0.2.0/24 and specify the secondary IP range for pods at creation time. This is required because in Google Cloud VPC, secondary IP ranges are immutable after subnet creation—they cannot be added later, only removed. For a Kubernetes cluster, the secondary range is essential for pod networking, and the Google Professional Cloud Network Engineer exam frequently tests this constraint to ensure you understand that subnet configuration must be finalized upfront. A common trap is assuming you can modify or attach a secondary range post-creation, which would break cluster deployment. On the exam, this scenario appears as a straightforward subnet creation task, but the key is remembering that secondary ranges are a one-time assignment. Memory tip: “Subnets are set in stone; add your pods’ range when you’re alone”—meaning define the secondary range during the initial creation step.
PCNE Implementing a Virtual Private Cloud Practice Question
This PCNE practice question tests your understanding of implementing a virtual private cloud. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A company has a VPC with a subnet 10.0.1.0/24 in us-central1. They need to add a new subnet for a Kubernetes cluster that requires a secondary IP range for pods. The primary IP range of the new subnet must be 10.0.2.0/24. What is the correct way to create this subnet?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "primary"
Why it matters: Asks for the main purpose or function, not a secondary benefit. Eliminate answers that describe side-effects or partial functions.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Create the subnet with primary range 10.0.2.0/24 and specify the secondary range at creation time.
Option A is correct because in Google Cloud VPC, a subnet can have both a primary IP range and one or more secondary IP ranges, and these secondary ranges must be specified at subnet creation time. For a Kubernetes cluster, the secondary range for pods is required, and it cannot be added after the subnet is created; it must be defined during the initial subnet creation.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✓
Create the subnet with primary range 10.0.2.0/24 and specify the secondary range at creation time.
Why this is correct
Secondary ranges must be specified at subnet creation.
Clue confirmation
The clue word "primary" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
Create the subnet with primary range 10.0.2.0/24 and then update it to add the secondary range.
Why it's wrong here
Subnets cannot be updated after creation to add secondary ranges.
✗
Create two subnets: one with 10.0.2.0/24 for primary and another for the secondary range.
Why it's wrong here
Secondary ranges are part of the same subnet, not separate subnets.
✗
Create an auto mode subnet and let Google Cloud assign the secondary range automatically.
Why it's wrong here
Auto mode does not automatically assign secondary ranges.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Google Cloud often tests the misconception that secondary IP ranges can be added to an existing subnet via an update, but in Google Cloud, they must be specified at subnet creation time and are immutable afterward.
Detailed technical explanation
How to think about this question
In Google Cloud VPC, secondary IP ranges are used for Kubernetes pod IPs and services, and they must be defined when the subnet is created using the `gcloud compute networks subnets create` command with the `--secondary-range` flag. The secondary range cannot be added later via update, as the subnet's IP configuration is immutable after creation. This design ensures that the subnet's IP allocation is consistent and avoids conflicts with dynamic routing or overlapping ranges.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A healthcare organisation deploys an application with a public-facing web tier and a private database tier. The database subnet has no public IP and only accepts connections from the web tier's security group. Questions like this test whether you can design cloud network isolation using VNets/VPCs, subnets, and security group rules.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Implementing a Virtual Private Cloud — This question tests Implementing a Virtual Private Cloud — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Create the subnet with primary range 10.0.2.0/24 and specify the secondary range at creation time. — Option A is correct because in Google Cloud VPC, a subnet can have both a primary IP range and one or more secondary IP ranges, and these secondary ranges must be specified at subnet creation time. For a Kubernetes cluster, the secondary range for pods is required, and it cannot be added after the subnet is created; it must be defined during the initial subnet creation.
What should I do if I get this PCNE question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Are there clue words in this question I should notice?
Yes — watch for: "primary". Asks for the main purpose or function, not a secondary benefit. Eliminate answers that describe side-effects or partial functions.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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This PCNE practice question is part of Courseiva's free Google Cloud certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the PCNE exam.
Question Discussion
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