AWS Certified Cloud Practitioner Certification - Part 30

1. Right Answer: A
Explanation: The key to understanding spot instances is to look at the way that cloud service providers such as Amazon Web Services (AWS) operate. Cloud service providers invest in hardware resources and then release those resources (often on a per-hour basis) to subscribers. One of the problems with this business model, however, is that at any given time, there are likely to be compute resources that are not being utilized. These resources represent hardware capacity that AWS has paid for but are sitting idle, and not making AWS any money at the moment. Rather than allowing these computing resources to go to waste, AWS offers them at a substantially discounted rate, with the understanding that if someone needs those resources for running a normal EC2 instance, that instance will take priority over spot instances that are using the hardware resources at a discounted rate. In fact, spot instances will be stopped if the resources are needed elsewhere.https://awsinsider.net/articles/2017/09/25/aws-spot-instances-primer.aspx

2. Right Answer: B,C
Explanation:

3. Right Answer: D
Explanation: AWS Lambda is charging its users by the number of requests for their functions and by the duration, which is the time the code needs to execute. When code starts running in response to an event, AWS Lambda counts a request. It will charge the total number of requests across all of the functions used. Duration is calculated by the time when your code started executing until it returns or until it is terminated, rounded up near to 100ms. The AWS Lambda pricing depends on the amount of memory that the user used to allocate to the function.https://dashbird.io/blog/aws-lambda-pricing-model-explained/

4. Right Answer: A
Explanation: AWS Security Groups act like a firewall for your Amazon EC2 instances controlling both inbound and outbound traffic. When you launch an instance on Amazon EC2, you need to assign it to a particular security group. After that, you can set up ports and protocols, which remain open for users and computers over the internet. AWS Security Groups are very flexible. You can use the default security group and still customize it according to your liking (although we don't recommend this practice because groups should be named according to their purpose.) Or you can create a security group that you want for your specific applications. To do this, you can write the corresponding code or use the Amazon EC2 console to make the process easier.https://www.threatstack.com/blog/aws-security-groups-what-they-are-and-how-to-get-the-most-outof-them

5. Right Answer: D
Explanation: Backup and Restore: a simple, straightforward, cost-effective method that backs up and restores data as needed. Keep in mind that because none of your data is on standby, this method, while cheap, can be quite time-consuming.Pilot Light: This method keeps critical applications and data at the ready so that it can be quickly retrieved if needed. Warm Standby: This method keeps a duplicate version of your business' core elements running on standby at all times, which makes for a little downtime and an almost seamless transition.Multi-Site Solution: Also known as a Hot Standby, this method fully replicates your company's data/ applications between two or more active locations and splits your traffic/usage between them. If a disaster strikes, everything is simply rerouted to the unaffected area, which means you'll suffer almost zero downtime. However, by running two separate environments simultaneously, you will obviously incur much higher costs.https://cloudranger.com/best-practices-aws-disaster-recovery-planning/