Google ACE Practice Question: A company runs a batch processing workload on…

Answer analysis

Option-by-option breakdown

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

• ✓

  Use a preemptible custom machine type with 4 vCPUs and 8 GB memory.

  Why this is correct

  Preemptible instances are subject to termination by Compute Engine at any time (within 24 hours) but cost up to 60-91% less than standard VMs, making them ideal for idempotent or restartable batch work that runs only 30 minutes per day. A custom machine type with 4 vCPUs and 8 GB memory precisely matches your workload's resource requirements, avoiding the cost of the unused 8 GB included in a standard machine. This combination delivers the lowest effective cost while still being fault-tolerant: if a preemptible instance is reclaimed mid-job, you simply retry on a newly created instance.

• ✗

  Use a sole-tenant node with a machine type that matches the workload.

  Why it's wrong here

  A sole-tenant node dedicates a whole physical server to your project, isolating your VMs from other customers' workloads, which is a compliance or licensing feature rather than a cost saver. You are billed for the entire node regardless of how many VMs it hosts, so matching the machine type still leaves you paying for unused physical capacity and management overhead. For a fault-tolerant batch job that completes in 30 minutes, that dedicated capacity is neither required nor economically justified.

• ✗

  Use an N1 standard-4 machine without discounts.

  Why it's wrong here

  An N1 standard-4 machine ships with 16 GB of memory, but your workload only needs 8 GB, so you would be paying for 8 GB of unused RAM and a larger per-hour compute cost. Without preemptible, committed use, or sustained-use discounts, the on-demand rate applies to every VM-hour, and a standard machine also locks you to fixed resource ratios rather than a tuned custom shape. The cost per hour is simply higher than a 4-vCPU/8-GB custom preemptible for exactly the same batch workload.

• ✗

  Purchase a 1-year committed use discount for the appropriate machine type.

  Why it's wrong here

  A 1-year committed use discount requires you to reserve and pay for a specific vCPU/memory quantity continuously for the entire term, even when the VM is stopped; it only makes sense for always-on workloads with predictable baseline usage. Since this batch job runs only 30 minutes per day, a commitment would pay for many hours every day that are not used, and Google Cloud does not allow preemptible VMs to be covered by committed use contracts anyway. Preemptible on-demand instances are a far better fit for this short, restartable workload.

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