Concepts
Amazon EC2 (Elastic Compute Cloud) is a fundamental part of AWS, providing scalable compute capacity in the cloud. When preparing for the AWS Certified SysOps Administrator – Associate (SOA-C02) exam, understanding how to enhance EC2 capabilities is crucial for optimizing performance and functionality. We will explore Elastic Network Adapters (ENAs), instance store volumes, and placement groups, on how to enable and utilize them.
Elastic Network Adapters (ENAs)
Elastic Network Adapters provide high-performance networking capabilities for EC2 instances. They support up to 100 Gbps of network bandwidth and advanced networking features such as Enhanced Networking, which reduces latency, jitter, and CPU utilization.
To enable ENA on an EC2 instance, you must first ensure that the instance type supports ENA. This capability is present in many current-generation instance types such as the M5, C5, and R5 families. Here are the general steps to enable Enhanced Networking with ENA:
- Launch an instance that supports ENA, typically a current-generation instance type.
- Verify that the ENA driver is installed within the instance’s operating system.
- If creating your own AMI, ensure that the ENA support is enabled.
- If it is not enabled, you can enable it using the AWS CLI with the following command:
aws ec2 modify-instance-attribute –instance-id i-1234567890abcdef0 –ena-support
Instance Store Volumes
Instance store provides temporary block-level storage for your instance. This storage is located on disks that are physically attached to the host computer. Instance store volumes offer high I/O performance but are ephemeral in nature, meaning the data is lost if the instance is stopped, terminated, or if the underlying disk fails.
Instance store volumes cannot be added to an instance after it has been launched. To make use of instance store volumes:
- Choose an instance type that includes instance store volumes such as the I3 or D2 instances.
- Launch the instance, including the instance store volumes in your block device mapping. This can be done either through the EC2 launch wizard or using the command line.
Here’s an example of EC2 block device mapping to include instance store volumes using the AWS CLI:
aws ec2 run-instances –image-id ami-abcdefgh –count 1 –instance-type i3.large –block-device-mappings file://mapping.json
In this mapping.json file, you would specify the instance store volumes. Example content for mapping.json could look like:
[
{
“DeviceName”: “/dev/sdb”,
“VirtualName”: “ephemeral0”
},
{
“DeviceName”: “/dev/sdc”,
“VirtualName”: “ephemeral1”
}
]
Placement Groups
AWS offers placement groups to influence the placement of a set of interdependent instances to meet the needs of your workload. Placement groups come in three types: cluster, spread, and partition.
- Cluster placement groups ensure that instances are placed onto a low-latency network in the same Availability Zone and are suitable for applications that need high network throughput and low latency.
- Spread placement groups place instances across distinct underlying hardware to reduce the risk of simultaneous failures and are suitable for applications that need to minimize the risk of simultaneous failures.
- Partition placement groups spread EC2 instances across logical partitions, ensuring that instances in one partition do not share the underlying hardware with instances in other partitions.
To create a placement group:
- Open the Amazon EC2 console.
- Navigate to “Placement Groups” under “EC2 Dashboard” and choose “Create Placement Group”.
- Specify the name and the placement strategy (cluster, spread, partition).
- Launch the instances into the placement group by specifying the placement group name during the launch process.
For example, when using the AWS CLI, you can specify the placement group in the run-instances command:
aws ec2 run-instances –image-id ami-abcdefgh –count 1 –instance-type c5.large –placement GroupName=my-cluster-placement-group
Understanding and enabling these enhanced EC2 capabilities are essential for those seeking AWS Certified SysOps Administrator – Associate certification. They are necessary for optimizing the performance and reliability of applications running on AWS EC2 instances.
Answer the Questions in Comment Section
True or False: The Elastic Network Adapter (ENA) provides higher throughput and lower latency than traditional network adapters on EC
- Answer: True
ENA is designed to provide high throughput and low latency for EC2 instances, supporting up to 100 Gbps for selected instance types.
True or False: Instance Store provides durable storage that persists across reboots and stopping/starting the EC2 instance.
- Answer: False
Instance Store provides ephemeral storage, which means the data is lost if the instance is stopped, terminated, or if the underlying disk fails.
True or False: Placement groups are optional and can be used to influence the placement of instances within a region.
- Answer: True
Placement groups can be used to determine how instances are placed and can be used to either cluster instances together or spread them across underlying hardware.
What is the purpose of a spread placement group in AWS EC2?
- A. To provide high availability by spreading instances across multiple Availability Zones
- B. To improve network performance by placing instances close to each other
- C. To maintain low latency between instances by placing them in close proximity
- D. To spread instances across underlying hardware to reduce correlated failures
- Answer: D
Spread placement groups distribute instances across diverse underlying hardware to minimize correlated failures.
Can Enhanced Networking be used with any type of EC2 instance?
- A. Yes, all EC2 instances support Enhanced Networking
- B. No, only selected EC2 instance types support Enhanced Networking
- C. Enhanced Networking is only available in specific AWS regions
- D. It is an advanced feature that requires manual activation for each instance
- Answer: B
Enhanced Networking with ENA is available only for selected EC2 instance types that meet the requirements.
When using an instance store-backed EC2 instance, in which scenarios will you lose your data? (Select two)
- A. Rebooting the instance
- B. Stopping the instance
- C. Terminating the instance
- D. Detaching the instance store volume
- Answer: B, C
Data on an instance store volume is lost when the instance is stopped or terminated. Rebooting does not affect the data, and instance store volumes cannot be detached as they are physically attached to the host computer.
True or False: Any EC2 instance can be launched into a placement group.
- Answer: False
Not all instance types can be launched into a placement group, and there are restrictions based on the type of placement group used.
True or False: An Elastic Network Adapter supports TCP offload to enhance performance.
- Answer: True
ENA supports various offload technologies, including TCP Segmentation Offload, which enhances performance by offloading the TCP processing to the network adapter.
Which instance type is ideal for workloads requiring a high amount of temporary storage with very low latency and high random I/O performance?
- A. Instances with EBS-optimized storage
- B. Instances with attached Elastic Network Adapters
- C. Instances backed by EC2 instance store
- D. Instances within a dedicated host placement group
- Answer: C
EC2 instance store provides temporary block-level storage with very low latency and high I/O performance, ideal for such workloads.
If you want to use Enhanced Networking with ENA, what must your instance’s operating system have?
- A. The latest version of Java installed
- B. An ENA driver
- C. A custom Amazon Machine Image (AMI)
- D. Sufficient IAM role permissions
- Answer: B
Enhanced Networking with ENA requires that the instance’s operating system has the ENA driver installed to utilize the benefits of ENA.
True or False: You can change the placement group of an existing EC2 instance without stopping it.
- Answer: False
To move an existing EC2 instance to a different placement group or remove it from one, the instance must be stopped and then started again.
What is the maximum number of instances that can be launched in a single cluster placement group?
- A. 7 instances per Availability Zone
- B. The limit varies by the type of instance selected
- C. 20 instances per region
- D. There is no fixed limit, it depends on the available capacity
- Answer: D
The number of instances that can be launched in a cluster placement group depends on the available capacity for the selected instance type and the region, so there is no fixed limit.
Great post! I learned a lot about the Elastic Network Adapter and how it enhances network performance for EC2 instances.
Thanks for the detailed explanation on instance stores. It clarified many of my doubts.
Can anyone explain the significance of placement groups in AWS EC2?
Is it true that Elastic Network Adapter can achieve up to 100 Gbps network throughput?
Appreciate the blog post, it helped me understand the importance of placement groups in high-availability setups.
How do placement groups affect instance performance?
The blog was very informative. Can someone explain if there are any drawbacks of using instance stores?
Thanks for this invaluable resource on enhancing EC2 capabilities!