Google ACE Practice Question: Deploying a stateless web application on Compute…

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

• ✗

  Increase the initial delay for the load balancer health check to 5 minutes.

  Why it's wrong here

  Increasing the initial delay (initialDelaySec) on the load balancer health check tells Cloud Load Balancing to wait 5 minutes before it first probes the instance; during that entire grace period the LB will not mark the instance healthy, so the instance will not serve traffic. This does not shorten the application's boot time; it only postpones the moment traffic is routed, making apparent startup time worse.

• ✗

  Configure a startup script in the instance template that installs dependencies and starts the application.

  Why it's wrong here

  Running a startup script in the instance template that installs dependencies and starts the application moves package installation and configuration into the boot path. Each new VM must execute apt-get, pip install, or other network-dependent commands, which adds tens of seconds or minutes before the app can listen on its port. This approach increases, not reduces, startup time compared with baking dependencies into the image.

• ✗

  Set the managed instance group's autohealing to replace unhealthy instances based on the load balancer health check.

  Why it's wrong here

  Configuring managed instance group autohealing to replace instances that fail the load balancer health check improves availability by automatically recreating unhealthy VMs, but autohealing does nothing to speed up a single instance's boot-to-ready time. When a replacement is created, it still has to go through the same slow boot, container pull, or startup-script process before it can pass the health check and receive traffic.

• ✓

  Use a container-optimized OS and deploy the application as a Docker container via the startup script.

  Why this is correct

  Container-Optimized OS is a minimal, hardened Linux distribution from Google that boots very quickly and is preconfigured to run Docker containers. If the container image is already cached on the boot disk or in a nearby registry, the startup script can simply run docker start or docker run, launching the application and its dependencies in seconds and eliminating per-instance package installation.

• ✓

  Create a custom machine image that includes the application and all dependencies.

  Why this is correct

  Creating a custom machine image with the application and all dependencies already baked into the boot disk means new instances start with the software in place; after the VM boots, the app can begin serving immediately, without running installers or download scripts. This is a classic fast-start practice for stateless workloads because it removes the variability and delay of installing at instance creation time, though the image itself must be updated when the app changes.

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