Squeeze Every Last Drop Out of Your GCP Budget: Committed Use Discounts & Sustained Use

Running your applications on Google Cloud Platform (GCP) offers incredible flexibility and scalability. But with great power comes great responsibility… the responsibility to manage your costs effectively! Luckily, GCP provides tools to help you do just that. Today, we’re diving into two powerful cost optimization strategies: Committed Use Discounts (CUDs) and Sustained Use Discounts (SUDs).

Think of it like buying in bulk at the grocery store or getting a discount for being a loyal customer – GCP rewards you for using their resources consistently!

What are Committed Use Discounts (CUDs)?

Imagine you’re opening a bakery. You know you’ll need a certain amount of flour every month for the next year. You could buy small bags as you go, but it’s often cheaper to commit to buying a large quantity upfront. That’s essentially what CUDs are.

CUDs are a significant discount you get in exchange for committing to using a specific amount of compute resources (like vCPUs and memory) in a specific region for a 1-year or 3-year term.

Key things to remember about CUDs:

• Commit, Don’t Consume: You’re committing to using the resources, not necessarily consuming them 24/7. Even if your VM isn’t running all the time, you still pay for the committed amount.
• Predictability is Key: CUDs work best when you have a predictable workload. Think long-running applications, databases, or other services that are always “on.”
• Region Specific: Commitments are tied to a specific region. For example, a commitment in us-central1 can’t be used for resources in us-east1.
• Size Matters: You can choose the commitment size that best fits your needs. You don’t have to commit to the entire resource pool.
• Discount Rates: 1-year commitments offer a lower discount than 3-year commitments. Plan ahead for maximum savings!

How to use CUDs:

1. Analyze your usage: Use GCP’s cost management tools to understand your historical resource consumption. Identify resources that are consistently used.
2. Choose your commitment: Based on your analysis, determine the vCPU and memory commitment that aligns with your long-term needs.
3. Purchase the commitment: You can purchase commitments through the GCP Console or using the gcloud command-line tool.
4. Monitor your usage: Continue to monitor your resource utilization to ensure your commitment remains aligned with your needs.

Why use CUDs?

• Significant Cost Savings: CUDs can reduce your compute costs by a substantial margin (often 30-70%), especially for 3-year commitments.
• Budget Predictability: Knowing your base compute costs in advance makes budgeting and forecasting much easier.
• Encourages Right-Sizing: The commitment encourages you to carefully assess your resource requirements and optimize your VM configurations.

What are Sustained Use Discounts (SUDs)?

Think of SUDs as a loyalty program for long-running instances. The longer you run a Compute Engine instance throughout the month, the more you save. Unlike CUDs, you don’t need to make any upfront commitment. The discount is applied automatically based on your usage.

SUDs are automatic discounts you get for running Compute Engine instances (vCPUs and memory) for a significant portion of the billing month.

Key things to remember about SUDs:

• Automatic, No Commitment Needed: The biggest advantage is that you don’t have to sign any contracts or make any upfront commitments.
• Longer Run = Bigger Discount: The longer your instance runs, the higher the discount. You get the maximum discount if your instance runs for the entire month.
• Apply to most Compute Engine instances: SUDs apply to most general-purpose, memory-optimized, and compute-optimized instance types.
• Discount tiers: The discounts are tiered. You get a base discount for running the instance for a portion of the month, and then the discount increases as the instance runs longer.
• Interruptible VMs don’t qualify: Preemptible (now called Interruptible) VMs aren’t eligible for SUDs.

How do SUDs work?

You don’t have to do anything special to benefit from SUDs. Just keep your instances running! The discounts are automatically applied to your bill at the end of the billing cycle. The longer the instance runs during the month, the higher the discount.

Why use SUDs?

• Automatic Cost Savings: You automatically benefit from discounts without any upfront commitment or complex configurations.
• Encourages Continuous Operations: If you need to run your workloads consistently, SUDs incentivize you to keep them running for longer periods, maximizing your savings.
• Simplicity: SUDs are easy to understand and benefit from – just run your instances.

CUDs vs. SUDs: Which is right for you?

Feature	Committed Use Discounts (CUDs)	Sustained Use Discounts (SUDs)
Commitment	Required (1-year or 3-year)	No commitment required
Discount Rate	Higher (potential for greater savings)	Lower (but still significant)
Ideal For	Predictable, long-term workloads	Workloads that run consistently for a significant portion of the month
Effort	Requires planning and commitment purchase	Automatic – no action required

In a Nutshell:

• Choose CUDs if you have predictable workloads that you know will run for a year or more.
• Choose SUDs if you have workloads that need to run consistently for a significant portion of the month, and you want automatic cost savings without any upfront commitment.

Pro Tip: You can combine CUDs and SUDs! If your instance runs consistently within your CUD commitment, you’ll get the CUD discount and the additional SUD discount on top.

Conclusion

Committed Use Discounts and Sustained Use Discounts are valuable tools in your GCP cost optimization arsenal. By understanding how they work and aligning them with your workload patterns, you can significantly reduce your cloud spending and make your budget go further. So, take some time to analyze your usage, plan your commitments, and start saving! Happy clouding!