Single-Tenancy Environment

What are reserved instances?

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Reserved Instances (RIs) are a pricing and capacity reservation offering provided by AWS for their EC2 (Elastic Compute Cloud) and RDS (Relational Database Service) services.

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They specifically allow users to commit to using a specific instance type in the same region for either a one or three-year term, in exchange for discounts of up to 72% – the exact discount is ultimately dependent on the commitment term, instance type, availability zone and region.

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There are various types of Reserved Instances available, each with different terms and levels of flexibility. Standard Reserved Instances provide the highest cost savings but are the least flexible, whereas Convertible Reserved Instances offer more flexibility by allowing you to change instance families within the same instance type.

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In contrast, Scheduled Reserved Instances offer a lower discount, but allow you to reserve capacity for specific time windows, such as business hours or weekends, providing cost savings for predictable workloads.

What are spot instances?

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As with any cloud service provider, AWS will have spare capacity available to support surges in customer demand. To offset the loss, AWS offers this excess EC2 capacity – in other words, spot instances – at a heavily discounted rate.

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To benefit from these spot instances, users must bid on this unused EC2 capacity in their desired region. The capacity is then allocated to the highest bidder. While it can be a great way to reduce costs by as much as 90%, it is only suitable for workloads that can tolerate interruptions and don’t require continuous availability. This is because AWS will terminate the instance after a two-minute notification in the event that it needs to reclaim the resources, or because the spot price exceeds the bid price. In other words, when other customers are willing to pay more.

What is a multi-tenancy environment?

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In cloud computing, a multi-tenancy environment refers to a situation where multiple users, also referred to as tenants, share the same physical infrastructure and resources. These resources, such as computing power, memory and storage are dynamically allocated based on the needs of each tenant. Each tenant’s data is, however, stored in separate databases to ensure both privacy and security.

What is zero-based budgeting?

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Zero-based budgeting is an accounting technique that requires all expenses to be justified and approved for each financial period, starting from zero rather than a pre-existing spend. This enables organizations to monitor and assess the necessity of each cost on a more granular level, lowering expenses and promoting fiscal responsibility.

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Originally conceived in the 1970s, zero-based budgeting isn’t a new idea — but in the current economic climate, accounting for every dollar is helping businesses to regain control over their outgoings. The technique can be applied to a wide range of costs, from research and development to asset management.

What is tail spend?

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Tail spend refers to the unmanaged purchases made within an organization that fail to pass through an official procurement process. On account of their low value, the costs incurred by these purchases are seldom monitored by financing teams as they are generally too small to be deemed “strategic”. The problem, however, is that they can make up as much as 20% of a business’ total spend.

What is an instance in the context of cloud computing?

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In cloud computing, an instance refers to a virtual server provided by a third-party cloud service, for example AWS, Azure or Google Cloud. These instances ultimately enable companies to deploy and run their applications or services in the cloud, in a scalable and flexible manner. This is because instances are on-demand and can be adjusted based on your workload requirements.