SOA-C01 : AWS-SysOps ​​​​​: Part 21

SOA-C01 : AWS-SysOps ​​​​​: Part 21

1. By default, how many Elastic IP addresses can you have per region for your EC2 instances?

   • 10
   • 2
   • 20
   • 5
   Explanation:
   The number of Elastic IP addresses you can have in EC2 per region is 5.

2. Elasticity is one of the benefits of using Elastic Beanstalk. Which of the following best describes the concept of elasticity?

   • It is the ability for counting the number of architectural design considerations that are required to develop a console.
   • It is the streamlining of resource acquisition and release, so that your infrastructure can rapidly scale in and scale out as demand fluctuates.
   • It is the process of examining the amount of security credentials required to access a data vol-ume.
   • It is the procedure of estimating the resource cost, so that you can run a specific project on AWS.
   Explanation:
   Because applications deployed using Elastic Beanstalk run on Amazon cloud resources, you should keep several things in mind when designing your application: scalability, security, persistent storage, fault tolerance, content delivery, software updates and patching, and connectivity. Elasticity is the streamlining of resource acquisition and release, so that your infrastructure can rapidly scale in and scale out as demand fluctuates.

3. What is an Auto Scaling group?

   • It is a group of ELBs that are used to add instances from various regions.
   • It is a logical grouping of EC2 instances that share similar characteristics for scaling and man-agement.
   • It is a collection of EC2 instance launch parameters with different characteristics for scaling and management.
   • It is a group of launch configurations for Elastic load balancers in the same region.
   Explanation:
   An Auto Scaling group contains a collection of EC2 instances that share similar characteristics and are treated as a logical grouping for the purposes of instance scaling and management.

4. Which service is offered by Auto Scaling?

   • Automatic scaling storage
   • Automatic scale EC2 capacity
   • Automatic scale ECS capacity
   • Automatic scale elastic IP
   Explanation:
   Auto Scaling is a service that allows users to scale the EC2 resources up or down automatically ac-cording to the conditions or by manual intervention. It is a seamless process to scale the EC2
   compute units up and down.

5. Which of the scaling options given below is not supported by Auto Scaling?

   • All these options are supported by Auto Scaling
   • Manual scaling
   • Scaling based on CPU utilization
   • Scaling based on time
   Explanation:
   Auto Scaling supports three types of scaling:
   Manual scaling
   Scaling based on condition (e.g. CPU utilization is up or down, etc.) Scaling based on time (e.g. First day of the quarter, 6 am every day, etc.).

6. Security groups in Amazon VPC ______.

   • control incoming traffic only
   • control both inbound and outbound traffic
   • control neither incoming nor outgoing traffic
   • control outgoing traffic only
   Explanation:
   Security Groups in VPC allow you to specify rules for both outgoing and incoming traffic.

7. ______ in VPC are stateful where return traffic is automatically allowed, regardless of any rules.

   • Security groups
   • Availability Zones
   • Network ACLs
   • Geo Redundant Servers
   Explanation:
   Security groups in VPC are stateful where return traffic is automatically allowed without having to go through the whole evaluation process again. Network ACLs are stateless, meaning return traffic must be explicitly allowed by rules.

8. What happens if the instance launched by Auto Scaling becomes unhealthy?

   • Auto Scaling will terminate the instance and launch a new healthy instance.
   • Auto Scaling will terminate the instance but not launch a new instance.
   • The instance cannot become unhealthy.
   • Auto Scaling will notify the user and the user can update the instance.
   Explanation:
   Auto Scaling keeps checking the health of the EC2 instances launched by it at regular intervals. If an instance is observed as unhealthy, Auto Scaling will automatically terminate the instance and launch a new healthy instance. Thus, it maintains the number of instances as per the Auto Scaling group configuration.

9. A user has set the Alarm for the CPU utilization > 50%. Due to an internal process, the current CPU utilization will be 80% for 6 hours. How can the user ensure that the CloudWatch alarm does not perform any action?

   • The user can disable the alarm using the DisableAlarmActions API.
   • The user can set CloudWatch in a sleep state using the CLI mon-sleep-alarm-action.
   • The user can pause the alarm from the console.
   • The user cannot stop the alarm from performing an action unless the alarm is deleted.
   Explanation:
   The user can disable or enable the CloudWatch alarm using the DisableAlarmActions and Ena-bleAlarmActions APIs or the mon-disable-alarm-actions and mon-enable-alarm-actions commands.

10. A user is sending a custom metric to CloudWatch. If the call to the CloudWatch APIs has different dimensions, but the same metric name, how will CloudWatch treat all the requests?

    • It will treat each unique combination of dimensions as a separate metric.
    • It will group all the calls into a single call.
    • It will overwrite the previous dimension data with the new dimension data.
    • It will reject the request as there cannot be a separate dimension for a single metric.
    Explanation:
    A dimension is a key-value pair used to uniquely identify a metric. CloudWatch treats each unique combination of dimensions as a separate metric. Thus, if the user is making 4 calls with the same metric name but a separate dimension, it will create 4 separate metrics.

11. A user has enabled the CloudWatch alarm to estimate the usage charges. If the user disables moni-toring of the estimated charges but does not delete the billing alert from the AWS account, what will happen?

    • The user cannot edit the existing billing alarm.
    • The data collection on estimated charges is stopped.
    • It is not possible to disable monitoring of the estimated charges.
    • AWS will stop sending the billing alerts to the user.
    Explanation:
    To create an alarm on the estimated AWS usage charges, a user must enable monitoring of estimated AWS charges. This enables creating the metric data, which will be used to create a billing alarm. Once the estimated charges monitoring is enabled, the user cannot disable it. The user has to delete the alarms to stop receiving any notifications on billing.

12. What does enabling a sticky session with ELB do?

    • Routes all the requests to a single DNS
    • Ensures that all requests from the user’s session are sent to multiple instances
    • Binds the user session with a specific instance
    • Provides a single ELB DNS for each IP address
    Explanation:
    By default, a load balancer routes each request independently to the registered instance with the smallest load. However, you can use the sticky session feature (also known as session affinity), which enables the load balancer to bind a user’s session to a specific instance. This ensures that all requests from the user during the session are sent to the same instance.

13. Which of the following statements is true of an Auto Scaling group?

    • An Auto Scaling group cannot span multiple regions.
    • An Auto Scaling group delivers log files within 30 minutes of an API call.
    • Auto Scaling publishes new log files about every 15 minutes.
    • An Auto Scaling group cannot be configured to scale automatically.
    Explanation:
    An Auto Scaling group can contain EC2 instances that come from one or more Availability Zones within the same region. However, an Auto Scaling group cannot span multiple regions.

14. Which of the following activities is NOT performed by the Auto Scaling policy?

    • Changing instance types
    • Scaling up instance counts
    • Maintaining current instance levels
    • Scaling down instance counts
    Explanation:
    Auto Scaling policies can scale up or down based on the user-defined policies, health status checks or schedules. It also performs a health check on the instances, terminates unhealthy instances, and launches healthy instances to maintain the current instance level. Scaling provides you with options, outside of scaling policies, to override attributes from the instance and use the values that you need. For example, you can override the instance type using AWS CLI commands.

15. Which of the following services is used to monitor the Amazon Web Services resources?

    • AWS CloudWatch
    • AWS Cloudfront
    • AWS Monitor
    • AWS EC2
    Explanation:
    AWS CloudWatch is a service used to monitor the AWS resources and the applications running on EC2. It collects and tracks the metrics of various services or applications.

16. What is Amazon Import/Export?

    • A properly configured service role and instance profile
    • An international shipping division to help you enhance your sales reach
    • A service that accelerates transferring large amounts of data into and out of AWS using physical storage appliances
    • A software developed by Amazon to migrate the data from/to your datacenter to AWS
    Explanation:
    AWS Import/Export accelerates transferring large amounts of data between the AWS cloud and portable storage devices that you mail to us. AWS transfers data directly onto and off of your stor-age devices using Amazon high-speed internal network.

17. Which of the choices below best describes what Auto Scaling is well suited for?

    • only for applications that experience hourly, daily, or weekly variability in usage.
    • Both for applications that have stable demand patterns and that experience hourly, daily, or weekly variability in usage.
    • Both for applications that use frameworks and SDKs to enhance its customer relationship.
    • only for applications with a stable usage pattern but extremely high workload.
    Explanation:
    Auto Scaling is well suited to both applications that have stable demand patterns and that experi-ence hourly, daily, or weekly variability in usage. Whether the demand is predictable or unpredicta-ble auto scaling can be a good choice. If the demand is predictable and long term you may choose reserved instances. If the demand is unpredictable you may choose on-demand or even spot instance (if you can afford to have an instance lost unexpectedly).

18. True or False: Amazon Route 53 provides highly available and scalable Domain Name System (DNS), domain name registration, and health-checking web services.

    • False, you can only import an existing domain using Amazon Route 53.
    • True, however, it only provides .com domains.
    • FALSE
    • TRUE
    Explanation:
    Amazon Route 53 provides highly available and scalable Domain Name System (DNS), domain name registration, and health-checking web services.

19. Which of the following statements is true of Elastic Load Balancing?

    • It distributes traffic only to instances across different Availability Zones.
    • It distributes the outgoing traffic across multiple EC2 instances.
    • It distributes incoming traffic across multiple EC2 instances.
    • It distributes traffic only to instances across a single Availability Zone.
    Explanation:
    Elastic Load Balancing automatically distributes incoming traffic across multiple EC2 instances.
    You create a load balancer and register instances with the load balancer in one or more Availability Zones. The load balancer serves as a single point of contact for clients.

20. You are setting up a VPC and you need to set up a public subnet within that VPC. Which following requirement must be met for this subnet to be considered a public subnet?

    • Subnet’s traffic is not routed to an internet gateway but has its traffic routed to a virtual private gateway.
    • Subnet’s traffic is routed to an internet gateway.
    • Subnet’s traffic is not routed to an internet gateway.
    • None of these answers can be considered a public subnet.
    Explanation:
    A virtual private cloud (VPC) is a virtual network dedicated to your AWS account. It is logically isolated from other virtual networks in the AWS cloud. You can launch your AWS resources, such as Amazon EC2 instances, into your VPC. You can configure your VPC: you can select its IP ad-dress range, create subnets, and configure route tables, network gateways, and security settings. A subnet is a range of IP addresses in your VPC. You can launch AWS resources into a subnet that you select. Use a public subnet for resources that must be connected to the internet, and a private subnet for resources that won’t be connected to the Internet. If a subnet’s traffic is routed to an in-ternet gateway, the subnet is known as a public subnet. If a subnet doesn’t have a route to the Inter-net gateway, the subnet is known as a private subnet. If a subnet doesn’t have a route to the internet gateway, but has its traffic routed to a virtual private gateway, the subnet is known as a VPN-only subnet.