Amazon (SAP-C01) Exam Questions And Answers page 54

A Virtual Private Cloud (VPC) is a virtual network dedicated to the user's AWS account. It enables the user to launch AWS resources into a virtual network that the user has defined. AWS provides two features that the user can use to increase security in VPC: security groups and network ACLs. When the user wants to setup both the DB and App on VPC, the user should make one public and one private subnet. The DB should be hosted in a private subnet and instances in that subnet cannot reach the internet. The user can allow an instance in his VPC to initiate outbound connections to the internet but prevent unsolicited inbound connections from the internet by using a Network Address Translation (NAT) instance.

A Virtual Private Cloud (VPC) is a virtual network dedicated to the user's AWS account. It enables the user to launch AWS resources into a virtual network that the user has defined. The VPC is always specific to a region. The user can create a VPC which can span multiple Availability Zones by adding one or more subnets in each Availability Zone. Each subnet must reside entirely within one Availability Zone and cannot span across zones.

If you need to host multiple websites (with different IPs) on a single EC2 instance, the following is the suggested method from AWS.
Launch a VPC instance with two network interfaces.
Assign elastic IPs from VPC EIP pool to those interfaces (Because, when the user has attached more than one network interface with an instance, AWS cannot assign public IPs to them.) Assign separate Security Groups if separate Security Groups are needed This scenario also helps for operating network appliances, such as firewalls or load balancers that have multiple private IP addresses for each network interface.

The Amazon EC2 console provides a "Launch more like this" wizard option that enables the user to use a current instance as a template for launching other instances. This option automatically populates the Amazon EC2 launch wizard with certain configuration details from the selected instance.
The following configuration details are copied from the selected instance into the launch wizard: AMI ID
Instance type
Availability Zone, or the VPC and subnet in which the selected instance is located Public IPv4 address. If the selected instance currently has a public IPv4 address, the new instance receives a public IPv4 address - regardless of the selected instance's default public IPv4 address setting.
For more information about public IPv4 addresses, see Public IPv4 Addresses and External DNS Hostnames.
Placement group, if applicable
IAM role associated with the instance, if applicable Shutdown behavior setting (stop or terminate) Termination protection setting (true or false)
CloudWatch monitoring (enabled or disabled) Amazon EBS-optimization setting (true or false)
Tenancy setting, if launching into a VPC (shared or dedicated) Kernel ID and RAM disk ID, if applicable
User data, if specified
Tags associated with the instance, if applicable Security groups associated with the instance
The following configuration details are not copied from your selected instance; instead, the wizard applies their default settings or behavior:
(VPC only) Number of network interfaces: The default is one network interface, which is the primary network interface (eth0).
Storage: The default storage configuration is determined by the AMI and the instance type.

A Virtual Private Cloud (VPC) is a virtual network dedicated to the user's AWS account. The user can create subnets as per the requirement within a VPC. The VPC is always specific to a region. The user can create a VPC which can span multiple Availability Zones by adding one or more subnets in each Availability Zone. The instance launched will always be in the same availability zone of the respective subnet. When creating an EBS the user cannot specify the subnet or VPC. However, the user must create the EBS in the same zone as the instance so that it can attach the EBS volume to the running instance.

Amazon CloudWatch alarm watches a single metric over a time period that the user specifies and performs one or more actions based on the value of the metric relative to a given threshold over a number of time periods. The user can setup an action which terminates the instances when their CPU utilization is below a certain threshold for a certain period of time. The EC2 action can either terminate or stop the instance as part of the EC2 action.

For Amazon Web Services, the reserved instance (standard or convertible) helps the user save money if the user is going to run the same instance for a longer period. Generally, if the user uses the instances around 30-40% of the year annually it is recommended to use RI. Here as the instance runs only for 1 hour 50 minutes daily, or less than 8 percent of the year, it is not recommended to have RI as it will be costlier. At its highest potential savings, you are still paying 25 percent of an annual cost for a reserved instance you are you using less than 2 hours a day, (or less than 8 percent of each year) you are not saving money. Even a scheduled reserved instance has a key limitation, which is that it cannot be stopped or rebooted, only manually terminated with a possibility that it could be restarted. You would have to terminate and restart it within the 1 hour 50-minute window, otherwise you would need to wait until the next day. For a critical daily process, this is likely not an option. Spot Instances are not ideal because the process is critical, and must run for a fixed length of time at a fixed time of day. Spot instances would stop and start based on fluctuations in instance pricing, leaving this process potentially unfinished. The user should use on-demand with EBS in this case. While it has the highest cost, it also has the greatest flexibility to ensure that a critical process like this is always completed.

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.

Provisioned IOPS volumes are designed to meet the needs of I/O-intensive workloads, particularly database workloads that are sensitive to storage performance and consistency in random access I/O throughput. Provisioned IOPS volumes are designed to meet the needs of I/O-intensive workloads, particularly database workloads, that are sensitive to storage performance and consistency in random access I/O throughput business applications, database workloads, such as NoSQL DB, RDBMS, etc.

A Provisioned IOPS (SSD) volume can range in size from 4 GiB to 16 TiB and you can provision up to 20,000 IOPS per volume.