Free CLF-C02 flashcards

How can you script the launch of many identical Amazon EC2 instances and re-run that launch automatically on a schedule?

Use the AWS Command Line Interface (AWS CLI). It exposes AWS service operations as terminal commands, so the launch can be embedded in a shell script and re-run by a scheduled job. This gives repeatable, automated provisioning that a point-and-click graphical console cannot.

The AWS Management Console is a good fit for a nightly automated job that launches dozens of EC2 instances.

The console is a manual web interface operated by pointing and clicking through browser pages. It cannot be embedded in a scheduled script, so it forces an engineer to launch every instance by hand. Scripted, repeatable provisioning needs the AWS CLI instead.

On Amazon EC2, who patches the guest operating system, and why?

The customer does. Amazon EC2 is an infrastructure service where the responsibility boundary sits at the guest OS, so patching, updating and hardening that OS is the customer's job. AWS secures the hardware, hypervisor and facilities beneath that boundary.

Maintaining the physical security of the data centres hosting your Amazon EC2 instances is a customer responsibility.

It is not. Physical security of the facilities is security OF the cloud, which AWS owns. Customers never see or access the hardware, so it can never be a customer task.

Why does the pay-as-you-go model of the AWS Cloud suit a startup that is unsure how many customers it will attract?

It trades a large upfront capital expense for a variable expense tied to usage. The startup consumes resources on demand and pays only for capacity it actually uses, so it avoids buying a server fleet before launch and matches spend to real demand.

Moving to AWS guarantees every workload runs faster than it would on the company's own hardware.

AWS makes no universal performance guarantee. Raw speed is not the benefit being offered; the financial advantage is trading upfront capital expense for usage-based variable expense, so a business avoids committing to hardware it may not need.

Which Amazon EC2 pricing model gives the lowest hourly rate for a steady, always-on workload expected to run for years?

Reserved Instances. Committing to a one-year or three-year term lets AWS offer a much lower hourly rate than On-Demand, so a stable workload running continuously for years pays far less than the standard rate.

On-Demand Instances are the cheapest choice for a steady production workload that runs continuously for three years.

On-Demand suits short or unpredictable workloads but charges the full standard rate. For steady multi-year usage a committed model like Reserved Instances costs far less, so On-Demand is the tempting default rather than the cheapest option.