Pass the Google Cloud Platform Professional-Cloud-Network-Engineer Questions and answers with ValidTests

A Shared VPC Admin can define a Security Admin by granting an IAM member the Security Admin (compute.securityAdmin) role to the host project. Security Admins manage firewall rules and SSL certificates.

This answer follows the Google-recommended practices for using privately used public IP (PUPI) addresses for GKE Pod address blocks1. The benefits of this approach are:

It allows you to use any public IP addresses that are not owned by Google or your organization for your Pods, which can help mitigate address exhaustion in your enterprise.

It prevents any external traffic from reaching your Pods, as Google Cloud does not route PUPI addresses to the internet or to other VPC networks by default.

It enables you to use VPC Network Peering to connect your GKE cluster to other VPC networks that use different PUPI addresses, as long as you enable the export and import of custom routes for the peering connection.

It preserves the fully integrated network model of GKE, where Pods can communicate with nodes and other resources in the same VPC network without NAT.

The options that you need to select when creating a private GKE cluster with PUPI addresses are:

–disable-default-snat: This option disables source NAT for outbound traffic from Pods to destinations outside the cluster’s VPC network. This is necessary to prevent Pods from using RFC 1918 addresses as their source IP addresses, which could cause conflicts with other networks that use the same address space2.

–enable-ip-alias: This option enables alias IP ranges for Pods and Services, which allows you to use separate subnet ranges for them. This is required to use PUPI addresses for Pods1.

–enable-private-nodes: This option creates a private cluster, where nodes do not have external IP addresses and can only communicate with the control plane through a private endpoint. This enhances the security and privacy of your cluster3.

Option A is incorrect because it does not use PUPI addresses for Pods, but rather RFC 1918 addresses. This does not solve the problem of address exhaustion in your enterprise. Option B is incorrect because it reuses the secondary address range for Services across multiple private GKE clusters, which could cause IP conflicts and routing issues. Option C is incorrect because it does not specify the options that are needed to create a private GKE cluster with PUPI addresses.

1: Configuring privately used public IPs for GKE | Kubernetes Engine | Google Cloud 2: Using Cloud NAT with GKE | Kubernetes Engine | Google Cloud 3: Private clusters | Kubernetes Engine | Google Cloud

Enabling Private Google Access on the subnet allows VMs to access Google APIs (like Cloud Storage and BigQuery) directly, without routing traffic over the internet. This approach is cloud-native and involves minimal setup, aligning with a cloud-first strategy.

Create Packet Mirroring Policies:

You need to create three packet mirroring policies, one for each zone (us-west2-a, us-west2-b, and us-west2-c). This ensures that each zone's traffic is mirrored appropriately without unnecessary cross-zone traffic.

Create Collector Instances:

Set up one group of collector instances for the us-west2 region. Having a single group of collector instances for the entire region minimizes the number of instances required and simplifies the management while keeping egress costs low since the collectors are within the same region.

Configuration of Policies:

Each packet mirroring policy should be configured to match traffic for its specific zone. Use instance-tags to identify and match the relevant instances within each zone. This helps in correctly capturing the traffic from the appropriate sources.

Filter for TCP Traffic:

Create a filter for TCP traffic (ports 80 and 443). This step ensures that only the relevant web application traffic is mirrored, reducing the amount of data processed and improving efficiency.

Cost Efficiency:

By having packet mirroring policies specific to each zone and a regional collector group, you reduce inter-zonal network egress costs. The data remains within the same region, avoiding extra charges associated with cross-zone traffic.

The problem description indicates that VMs in VPC2 receive traffic but their replies don't reach VPC1, especially when a VPN gateway fails. This strongly suggests an asymmetric routing issue, where VPC2's routing table might not be aware of all necessary routes to send return traffic to VPC1, particularly in a multi-region setup with failover. By default, VPC networks are in regional dynamic routing mode, meaning they only learn routes from Cloud Routers in the same region. To ensure that routes learned from one region (where the active VPN tunnel might be) are available globally across the VPC, you need to enable global dynamic routing mode in the VPC that is experiencing the return traffic issue (VPC2 in this case). This allows VPC2 to learn and apply routes from Cloud Routers in all regions, ensuring that even if a VPN tunnel fails in one region, the routes learned from the active tunnel in another region are still available for return traffic.

Exact Extract:

"A VPC network's dynamic routing mode controls whether routes learned by Cloud Routers in one region are available to VMs in other regions. By default, VPC networks are in regional dynamic routing mode, which means Cloud Routers in a region only advertise routes to and learn routes from other Cloud Routers in the same region. This can lead to asymmetric routing issues in multi-region deployments."

"To ensure that routes learned from Cloud Routers are propagated to all regions within a VPC network, you must set the dynamic routing mode to global."Reference: Google Cloud VPC Documentation - Dynamic routing mode

The correct answer is D. Create privately used public IP primary and secondary subnet ranges for the clusters. Create a private GKE cluster with the following options selected: --disable-default-snat, --enable-ip-alias, and --enable-private-nodes.

This answer is based on the following facts:

Privately used public IP (PUPI) addresses are any public IP addresses not owned by Google that a customer can use privately on Google Cloud1. You can use PUPI addresses for GKE pods and services in private clusters to mitigate address exhaustion.

A private GKE cluster is a cluster that has no public IP addresses on the nodes2. You can use private clusters to isolate your workloads from the public internet and enhance security.

The --disable-default-snat option disables source network address translation (SNAT) for the cluster3. This option allows you to use PUPI addresses without conflicting with other public IP addresses on the internet.

The --enable-ip-alias option enables alias IP ranges for the cluster4. This option allows you to use separate subnet ranges for nodes, pods, and services, and to specify the size of those ranges.

The --enable-private-nodes option enables private nodes for the cluster5. This option ensures that the nodes have no public IP addresses and can only communicate with other Google Cloud resources in the same VPC network or peered networks.

The other options are not correct because:

Option A is not suitable. Creating RFC 1918 primary and secondary subnet IP ranges for the clusters does not solve the problem of address exhaustion. Re-using the secondary address range for pods across multiple private GKE clusters can cause IP conflicts and routing issues.

Option B is also not suitable. Creating RFC 1918 primary and secondary subnet IP ranges for the clusters does not solve the problem of address exhaustion. Re-using the secondary address range for services across multiple private GKE clusters can cause IP conflicts and routing issues.

Option C is not feasible. Creating privately used public IP primary and secondary subnet ranges for the clusters is a valid step, but creating a private GKE cluster with only --enable-ip-alias and --enable-private-nodes options is not enough. You also need to disable default SNAT to avoid IP conflicts with other public IP addresses on the internet.