Passed Exam Today Associate-Cloud-Engineer

The requirement is for a stable set of egress IP addresses from a GKE cluster for allowlisting by a third party, following best practices.

Option A is not recommended: Using a single node lacks scalability and high availability. Relying on a single node's static IP creates a single point of failure and doesn't align with GKE's design principles. Disabling autoscaling hinders elasticity.

Option C is complex and unreliable: Public nodes typically have ephemeral external IPs (unless manually configured per node, which is difficult to manage with autoscaling). Dynamically tracking and emailing IPs daily is operationally burdensome and prone to race conditions where the allowlist might lag behind IP changes.

Option D uses Cloud NAT but with dynamic IPs. Dynamic IPs change over time, making them unsuitable for stable firewall allowlists.

Option B is the Google-recommended practice: Configuring the GKE cluster with private nodes enhances security as nodes don't have direct external IPs. Cloud NAT provides managed network address translation for these private nodes to access the internet. By configuring Cloud NAT with a static allocation of external IP addresses, all egress traffic from the private GKE nodes will appear to originate from this stable, predictable set of IPs. This set can be given to the vendor for allowlisting without worrying about node IP changes due to scaling or maintenance.

This approach decouples the application's egress IP from the individual nodes, providing stability and adhering to the principle of least privilege (private nodes).

IAP controls access to your App Engine apps and Compute Engine VMs running on Google Cloud. It leverages user identity and the context of a request to determine if a user should be allowed access. IAP is a building block toward BeyondCorp, an enterprise security model that enables employees to work from untrusted networks without using a VPN.

By default, IAP uses Google identities and IAM. By leveraging Identity Platform instead, you can authenticate users with a wide range of external identity providers, such as:

Email/password

OAuth (Google, Facebook, Twitter, GitHub, Microsoft, etc.)

SAML

OIDC

Phone number

Custom

Anonymous

This is useful if your application is already using an external authentication system, and migrating your users to Google accounts is impractical.

Two App engine can't be running on the same project: you can check this easy diagram for more

And you can't change location after setting it for your app

App Engine is regional and you cannot change an apps region after you set it. Therefore, the only way to have an app run in another region is by creating a new project and targeting the app engine to run in the required region (asia-northeast1 in our case).

Autopilot is more reliable and stable release gives more time to fix issues in new version of GKE