Why it matters
Ghanaian infrastructure adverts name compute, storage and database services directly. Almost every cloud app, from a hospital booking system to a MoMo merchant dashboard, is built from four building blocks. Knowing what each is for, and when to choose it, is the bulk of entry level cloud work.
Compute: virtual machines
A virtual machine (VM) is a computer made of software running on a provider's physical server. Virtualisation lets one big physical machine run many separate VMs. You choose the size (CPU and memory), the operating system image and the network, then connect with SSH. VMs give the most control and the most responsibility: you patch and secure the operating system. Examples: Amazon EC2, Azure Virtual Machines, Google Compute Engine.
Storage: object, block and file
- Object storage holds files of any kind (photos, backups, reports) in containers called buckets, reached over the web. It is cheap and nearly unlimited, and it can host a static website. Examples: Amazon S3, Azure Blob Storage, Google Cloud Storage.
- Block storage is a virtual hard disk attached to one VM.
- File storage is a shared folder several servers can use at once.
A common mistake is leaving a bucket open to the public. Buckets should be private unless you deliberately host public files.