Private Google Access in GCP - Commands & Configuration

Introduction

Sometimes, virtual machines in a private network need to reach Google services without using public internet. Private Google Access lets these machines connect securely without public IP addresses.

When you want virtual machines without public IPs to access Google Cloud APIs and services.

When you want to keep your network isolated but still use Google services like Cloud Storage or BigQuery.

When you want to improve security by avoiding public internet exposure for your VMs.

When you have a private subnet and need to allow access to Google services without adding NAT gateways.

When you want to reduce costs by avoiding NAT usage for Google service traffic.

Config File - private_google_access.yaml

private_google_access.yaml

resources:
- name: example-subnet
  type: compute.v1.subnetwork
  properties:
    region: us-central1
    network: projects/my-project/global/networks/default
    ipCidrRange: 10.0.0.0/24
    privateIpGoogleAccess: true

This configuration enables Private Google Access on a subnet named example-subnet in the us-central1 region. The key property privateIpGoogleAccess: true allows VMs in this subnet without public IPs to reach Google APIs privately.

Commands

This command enables Private Google Access on the subnet named example-subnet in the us-central1 region. It allows VMs without public IPs in this subnet to access Google services privately.

Terminal

gcloud compute networks subnets update example-subnet --region=us-central1 --enable-private-ip-google-access

Expected Output

Updated [https://www.googleapis.com/compute/v1/projects/my-project/regions/us-central1/subnetworks/example-subnet].

→

--enable-private-ip-google-access - Enables Private Google Access on the subnet.

→

--region - Specifies the region of the subnet.

Creates a VM named example-vm in the example-subnet without a public IP address. This VM will use Private Google Access to reach Google services.

Terminal

gcloud compute instances create example-vm --zone=us-central1-a --subnet=example-subnet --no-address

Expected Output

Created [https://www.googleapis.com/compute/v1/projects/my-project/zones/us-central1-a/instances/example-vm].

→

--no-address - Prevents assigning a public IP to the VM.

→

--subnet - Specifies the subnet for the VM.

SSH into the VM and run a curl command to access Google Cloud Storage API. This tests that Private Google Access is working without a public IP.

Terminal

gcloud compute ssh example-vm --zone=us-central1-a --command="curl https://storage.googleapis.com/storage/v1/b"

Expected Output

{"kind":"storage#buckets"

→

--command - Runs a command on the VM without opening an interactive shell.

Key Concept

If you remember nothing else from this pattern, remember: Private Google Access lets VMs without public IPs securely reach Google services inside your private network.

Common Mistakes

Not enabling Private Google Access on the subnet before creating VMs.

VMs without public IPs cannot reach Google services without this enabled.

Always enable Private Google Access on the subnet first using the gcloud command or subnet configuration.

Assigning public IPs to VMs and expecting Private Google Access to apply.

Private Google Access only affects VMs without public IPs; public IP VMs use normal internet routing.

Create VMs with --no-address flag to ensure they have no public IP and use Private Google Access.

Summary

Enable Private Google Access on your subnet to allow private VMs to reach Google services.

Create VMs without public IPs in that subnet to use Private Google Access.

Test connectivity by accessing Google APIs from the VM without a public IP.

Practice

1. What is the main purpose of Private Google Access in Google Cloud?

easy

A. Provide a VPN connection between Google Cloud and on-premises networks

B. Allow VMs with only private IPs to access Google APIs without using the public internet

C. Allow external users to access Google Cloud resources securely

D. Enable VMs to have public IP addresses automatically

Solution

1. Step 1: Understand Private Google Access purpose

   It allows virtual machines without public IP addresses to reach Google APIs and services securely.

2. Step 2: Compare options with this purpose

   Only Allow VMs with only private IPs to access Google APIs without using the public internet describes this feature correctly; others describe unrelated features.

3. Final Answer:

   Allow VMs with only private IPs to access Google APIs without using the public internet -> Option B

4. Quick Check:

   Private Google Access = Secure private VM API access [OK]

Hint: Private Google Access = private VM access to Google APIs [OK]

Common Mistakes:

• Confusing Private Google Access with VPN or public IP assignment
• Thinking it allows external user access
• Assuming it provides public IPs automatically

2. Which configuration enables Private Google Access on a subnet in Google Cloud?

easy

A. Set private_ip_google_access = false in the subnet settings

B. Enable firewall rule to allow all traffic

C. Assign a public IP to all VMs in the subnet

D. Set private_ip_google_access = true in the subnet settings

Solution

1. Step 1: Identify the correct subnet setting for Private Google Access

   The subnet must have private_ip_google_access set to true to enable this feature.

2. Step 2: Review options for correctness

   Only Set private_ip_google_access = true in the subnet settings correctly sets private_ip_google_access to true; others disable it or are unrelated.

3. Final Answer:

   Set private_ip_google_access = true in the subnet settings -> Option D

4. Quick Check:

   Enable private_ip_google_access = true [OK]

Hint: Enable private_ip_google_access = true on subnet [OK]

Common Mistakes:

• Setting private_ip_google_access to false
• Thinking public IPs are required
• Confusing firewall rules with Private Google Access

3. Given a VM in a subnet with private_ip_google_access = true and no public IP, what happens when it tries to reach https://storage.googleapis.com?

medium

A. The VM accesses the URL through Private Google Access without using the public internet

B. The VM accesses the URL only if a VPN is configured

C. The VM cannot reach the URL because it has no public IP

D. The VM must use a NAT gateway to reach the URL

Solution

1. Step 1: Understand Private Google Access behavior

   With private_ip_google_access enabled, VMs without public IPs can reach Google APIs like storage.googleapis.com privately.

2. Step 2: Analyze options based on this behavior

   The VM accesses the URL through Private Google Access without using the public internet correctly describes this private access; others incorrectly deny access or require VPN/NAT.

3. Final Answer:

   The VM accesses the URL through Private Google Access without using the public internet -> Option A

4. Quick Check:

   Private IP VM + private_ip_google_access = private API access [OK]

Hint: Private IP VM with private_ip_google_access can reach Google APIs [OK]

Common Mistakes:

• Assuming no access without public IP
• Thinking VPN or NAT is mandatory
• Confusing Private Google Access with general internet access

4. A subnet has private_ip_google_access set to false. A VM without a public IP in this subnet cannot reach Google APIs. What is the best fix?

medium

A. Create a firewall rule to allow all outbound traffic

B. Assign a public IP to the VM

C. Enable private_ip_google_access = true on the subnet

D. Configure a VPN to Google Cloud

Solution

1. Step 1: Identify cause of no access

   Private Google Access is disabled, so private IP VMs cannot reach Google APIs.

2. Step 2: Choose the best fix

   Enabling private_ip_google_access on the subnet allows private IP VMs to access Google APIs without public IPs.

3. Final Answer:

   Enable private_ip_google_access = true on the subnet -> Option C

4. Quick Check:

   Enable private_ip_google_access to fix private VM API access [OK]

Hint: Enable private_ip_google_access = true to fix private VM API access [OK]

Common Mistakes:

• Assigning public IPs unnecessarily
• Adding firewall rules that don't affect Private Google Access
• Thinking VPN is required for Google API access

5. You have two subnets: Subnet A with private_ip_google_access = true and Subnet B with it set to false. A VM in Subnet B without a public IP needs to access Google APIs securely. What is the best approach?

hard

A. Move the VM to Subnet A or enable private_ip_google_access on Subnet B

B. Assign a public IP to the VM in Subnet B

C. Set up a NAT gateway for Subnet B

D. Create a firewall rule allowing access to Google APIs

Solution

1. Step 1: Understand subnet settings impact

   Private Google Access must be enabled on the subnet for private IP VMs to reach Google APIs.

2. Step 2: Evaluate options for secure access

   Moving the VM to Subnet A or enabling private_ip_google_access on Subnet B ensures secure private access without public IPs.

3. Step 3: Consider security and best practice

   Assigning public IPs or NAT gateways exposes the VM to public internet, less secure than Private Google Access.

4. Final Answer:

   Move the VM to Subnet A or enable private_ip_google_access on Subnet B -> Option A

5. Quick Check:

   Enable private_ip_google_access or move VM for secure private API access [OK]

Hint: Enable private_ip_google_access or move VM to subnet with it enabled [OK]

Common Mistakes:

• Assigning public IPs unnecessarily
• Relying on firewall rules alone
• Ignoring subnet configuration for Private Google Access