EC2 Flashcards

Question

What's the use of using elastic IP address?

Answer 1

You can mask the failure of an instance or a software by rapidly remapping the address to another instance in your account.

Answer 2

By default, you get a private IP address for the internal AWS network and a public IP address. When we are doing SSH into our EC2 machine, we can't use the private IP because we are not in the same network. We can only use the public IP address. The public IP address can change if the instance is stopped and then started.

Answer 3

Placement groups are a logical grouping of instances. In AWS we don't control the hardware but we can let AWS know how we want are instances to be placed.

Answer 4

Cluster instances into a low latency group in a same rack and in a same availability zone. Pros: It can provide enhanced network speed of up to 10 gigabits per second gonna. Cons: if rack fails, all instances fail at the same time Use case: 1. Big data job that needs to complete fast. 2. Application that needs extremely low latency and high network throughput.

Answer 5

Instances spread across underlying hardware across availability zones. Pros: reduce risk in simultaneous failure. EC2 instances are on different physical hardware Cons: limited to 7 instances per AZ per placement group Use case: application that needs maximum high availability. Critical applications where each instance must be isolated from failure from each other.

Answer 6

**Partition** – spreads your instances across logical partitions such that groups of instances in one partition do not share the underlying hardware with groups of instances in different partitions. This strategy is typically used by large distributed and replicated workloads, such as Hadoop, Cassandra, and Kafka.

Answer 7

1. Elastic block store volume is a network drive you can attach to an instance while they are running. Since it's a network drive, there might be a bit of latency. Think of EBS as a network USB stick. 2. EBS volumes are like a network drive therefore, there could be a little bit of latency 3. It allows your instances to persist data, even after their termination. 4. They are bound to a specific availability zone. 5. You can attach multiple EBS volumes to an instance 6. They can only be mounted to one instance at a time - use Elastic File Store instead 7. Root EBS volumes are deleted on termination by default

Answer 8

Yes, EBS volume can be detached from an EC2 instance while it's running and attached to another one quickly.

Answer 9

Yes, it is. you've got built for all provisioned capacity. You can increase the capacity of the drive over time.

Answer 10

Yes, EBS volumes are locked to an availability zone. And EBS volume in US-E-1A cannot be attached to an instance in US-E-1B. You first need to take its snapshot to move it.

Answer 11

It controls EBS behavior when an EC2 instance terminates. By default, the root EBS volume is deleted [attribute enabled]. By default, any other attached EBS volume is not deleted [attribute disabled]. This attribute can be used when you need to preserve root volume when an instance is terminated.

Answer 12

It is not necessary to detach the volume, but it's recommended?

Answer 13

EBS is a snapshot archive * move a snapshot to an archive tier that is 75 percent cheaper * takes within 24 to 72 hours for restoring the archive Recycle bin for EBS is snapshots * set up rules to retain deleted snapshots so you can recover them after an accidental deletion * A specified attention (from one day to one year) Fast Snapshot Restore (FSR) * Forces all initialization of snapshot to have no latency on the first use

Answer 14

Take a snapshot, copy it to a S3 and then restore it another agency or region.

Answer 15

1. 2. General purpose SSD volume that balances price and performance for a wide variety of workloads. It is low cost and low latency. It is best used for the system boot volume, virtual desktop, development, and testing environment. 3. IO1 and IO2 (SSD): highest performance SSD volume for mission-critical com low latency or high throughput workloads. It should be used for critical business applications with sustained IOPS performance and database workload. 1. It supports EBS multi-attach. 4. St1 (HDD): low-cost HDD volume designed for frequently accessed, throughput-intensive workloads 5. SC1 (HDD): lowest-cost HDD volume designed for less frequently accessed workloads. HDD volumes cannot be boot volumes EBS volumes are categorized in size, throughput, and IOPS Only GP2/GP3 and IO1/IO2 can be used as boot volumes IO1 and IO2 can be shared with multiple instances at the same time.

Answer 16

EBS volumes is a network drive with good but limited performance. If you need a high-performance hardware disk, use the EC2 instance store. An instance store is a disk typically attached to the host computer. You'll specify instance store volume only when you launch it. * It offers better IO performance. * Easy to instance, lose their storage if they're stopped * Good for buffer/cache/scratch data/temporary content * risk of data loss if hardware fails * Backups and replication are your responsibility

Answer 17

AMI stands for Amazon machine image. In order to create AMI: 1. Start an EC2 instance and customize it 2. Stop the instance for data integrity 3. Build an AMI - this will also create EBS snapshots

Answer 18

Yes, instance store is ideal for temporary storage of information that change frequently such as buffers, cache, scratch data and other temporary content. Remember that cost of instance store is included in the instance charges so it can be more cost efficient than EBS provisioned IOPS

Answer 19

Instance store volume are sometimes called Ephemeral storage (non-persistent)

Answer 20

It can be used for content management, web serving, data sharing, WordPress.

Answer 21

1. It works only on Linux and not windows. 2. It uses NFSv4.1 protocol. 3. File system scales automatically, pay per use, no capacity planning

Answer 22

Security groups are used to control EFS access

Answer 23

* EFS can be mounted on hundreds of instances across AZ. * EFS can be used to share website files fill. * It is only used for Linux instances. * EFS is more expensive than EBS.

Answer 24

The classic load balancer is deprecated by AWS. It supports TCP (layer 4), HTTP, and HTTP (layer 7)

Answer 25

1. Application load balancer works on HTTP layer 7 2. Load balances multiple HTTP applications across machines 3. Load balancing to multiple applications on the same machine 4. routing to different target groups based on a path in the URL, hostname in URL, query string, or header 5. It's a great fit for microservices and container-based application

Answer 26

A target group is a logical group of targets. Targets can be easy to instances (can be managed by an autoscaling group), ECS tasks, lambda functions, and IP addresses (must be private IP).

Answer 27

Yes. But one target group can be a part of one Application load balancer

Answer 28

Yes it can be

Answer 29

Target groups are regional construct

Answer 30

Network load balancer operate at the connection level, routine connections to targets-Amazon EC2 instances, containers and IP addresses based on IP protocol data.

Answer 31

Dedicated Instances are Amazon EC2 instances that run in a VPC on hardware that’s dedicated to a single customer. Your Dedicated instances are physically isolated at the host hardware level from instances that belong to other AWS accounts. Dedicated instances allow automatic instance placement and billing is per instance. “Dedicated Host” is incorrect. An Amazon EC2 Dedicated Host is a physical server with EC2 instance capacity fully dedicated to your use. Dedicated Hosts can help you address compliance requirements and reduce costs by allowing you to use your existing server-bound software licenses. With dedicated hosts billing is on a per-host basis (not per instance).

Answer 32

Elastic file system is the only storage solution that provides a file system interface it also supports millions of files as requested. EFS only works with Linux instances

Answer 33

With MySQL, authentication is handled by AWSAuthenticationPlugin—an AWS-provided plugin that works seamlessly with IAM to authenticate your IAM users. Connect to the DB instance and issue the CREATE USER statement, as shown in the following example. CREATE USER jane\_doe IDENTIFIED WITH AWSAuthenticationPlugin AS ‘RDS’; The IDENTIFIED WITH clause allows MySQL to use the AWSAuthenticationPlugin to authenticate the database account (jane\_doe). The AS ‘RDS’ clause refers to the authentication method, and the specified database account should have the same name as the IAM user or role. In this example, both the database account and the IAM user or role are named jane\_doe.

Answer 34

Scaling out is the process in which EC2 instances are launched by the scaling policy

Answer 35

“Scaling in” is a process in which EC2 instances are terminated by the scaling policy. It is recommended to create a scale-in event for each scale-out event created

Answer 36

Dynamic scaling policies: **Target tracking scaling**—Increase and decrease the group's current capacity based on an Amazon CloudWatch metric and a target value. It works similarly to how your thermostat maintains your home's temperature—you select a temperature, and the thermostat does the rest. **Step scaling**—Based on the cloud watch alarm if CPU% goes beyond a certain threshold add 2 instances or remove 1 instance. **Scheduled Scaling**: anticipate ice scaling based on known usage patterns and schedule the scaling-out or scaling-in of the instances Predictive Scaling: The machine learning model will look at the historical usage pattern and scale the instances in advance.

Answer 37

**AddToLoadBalancer is suspended**: Amazon EC2 Auto Scaling launches the instances but does not add them to the load balancer target group or Classic Load Balancer. When you resume the AddToLoadBalancer process, it resumes adding instances to the load balancer when they are launched. However, it does not add the instances that were launched while this process was suspended. You must register those instances manually. **AlarmNotification is suspended**: Amazon EC2 Auto Scaling does not invoke scaling policies when a CloudWatch alarm threshold is in breach. When you resume AlarmNotification, Amazon EC2 Auto Scaling considers policies with alarm thresholds that are currently in breach. **AZRebalance is suspended:** Amazon EC2 Auto Scaling does not attempt to redistribute instances after certain events. However, if a scale-out or scale-in event occurs, the scaling process still tries to balance the Availability Zones. For example, during scale out, it launches the instance in the Availability Zone with the fewest instances. If the group becomes unbalanced while AZRebalance is suspended and you resume it, Amazon EC2 Auto Scaling attempts to rebalance the group. It first calls Launch and then Terminate. **HealthCheck is suspended:** Amazon EC2 Auto Scaling stops marking instances unhealthy as a result of EC2 and Elastic Load Balancing health checks. Your custom health checks continue to function properly. After you suspend HealthCheck, if you need to, you can manually set the health state of instances in your group and have ReplaceUnhealthy replace them. **InstanceRefresh is suspended:** Amazon EC2 Auto Scaling stops replacing instances as a result of an instance refresh. If there is an instance refresh in progress, this pauses the operation without canceling it. **ReplaceUnhealthy is suspended:** Amazon EC2 Auto Scaling stops replacing instances that are marked as unhealthy. Instances that fail EC2 or Elastic Load Balancing health checks are still marked as unhealthy. As soon as you resume the ReplaceUnhealthly process, Amazon EC2 Auto Scaling replaces instances that were marked unhealthy while this process was suspended. The ReplaceUnhealthy process calls Terminate first and then Launch. **ScheduledActions is suspended**: Amazon EC2 Auto Scaling does not run scheduled actions that are scheduled to run during the suspension period. When you resume ScheduledActions, Amazon EC2 Auto Scaling only considers scheduled actions whose scheduled time has not yet passed.

Answer 38

Per the default termination policy, the first priority is given to any allocation strategy for On-Demand vs Spot instances. The next priority is to consider any instance with the oldest launch template unless there is an instance that uses a launch configuration. The next priority is the one that's closest to the next billing cycle

Answer 39

1. Amazon EC2 Auto Scaling does not immediately terminate instances with an Impaired status. Instead, Amazon EC2 Auto Scaling waits a few minutes for the instance to recover. Amazon EC2 Auto Scaling might also delay or not terminate instances that fail to report data for status checks. This usually happens when there is insufficient data for the status check metrics in Amazon CloudWatch. 2. **The instance has failed the ELB health check status** - By default, Amazon EC2 Auto Scaling doesn't use the results of ELB health checks to determine an instance's health status when the group's health check configuration is set to EC2. As a result, Amazon EC2 Auto Scaling doesn't terminate instances that fail ELB health checks. If an instance's status is OutofService on the ELB console, but the instance's status is Healthy on the Amazon EC2 Auto Scaling console, confirm that the health check type is set to ELB 3. **The health check grace period for the instance has not expired** - Amazon EC2 Auto Scaling doesn't terminate an instance that came into service based on EC2 status checks and ELB health checks until the health check grace period expires.

Answer 40

Yes it can, custom metrics that's sent to Amazon cloud watch that measures the number of messages in the queue for EC2 instance in the autoscaling group . Then use a target tracking policy that configures your auto scaling group to scale based on the custom metrics and set target value.

Answer 41

Cooldown period is a configuration setting for your autoscaling group that helps to ensure that it doesn't launch or terminate additional instances before the previous scaling activity takes place gonna stop. The default cooldown period is 300 seconds.

Answer 42

A security group acts as a virtual firewall for your EC2 instances to control incoming and outgoing traffic. Inbound rules control the incoming traffic to your instance, and outbound rules control the outgoing traffic from your instance. When you launch an instance, you can specify one or more security groups. one security group can be attached to multiple EC2 instances. If an application is not accessible (time out) to an EC2 instance, it means there is a security group issue. It only contains the “allow” rules. By default, all inbound traffic is blocked, and all outbound traffic is allowed.

Answer 43

It controls the access to ports, authorizes IP addresses(IPV4 or IPV 6), controls the inbound and outbound network. Security groups can authorize security groups and EC2 instances attached to them. We can control security groups without using IP addresses.

Answer 44

AWS Compute Optimizer helps you to avoid overprovisioning or underprovisioning three types of AWS resources—Amazon Elastic Compute Cloud (EC2) instance types, Amazon Elastic Block Store (EBS) volumes, and AWS Lambda functions—based on your utilization data.

Answer 45

The rightsizing recommendations feature in Cost Explorer helps you identify cost-saving opportunities by downsizing or terminating instances in Amazon Elastic Compute Cloud (Amazon EC2). Rightsizing recommendations analyze your Amazon EC2 resources and usage to show opportunities for how you can lower your spending.

Answer 46

Tenancy defines how EC2 instances are distributed across physical hardware and affects pricing. There are three tenancy options available: 1. Shared (default) — Multiple AWS accounts may share the same physical hardware. 2. Dedicated Instance (dedicated) — Your instance runs on single-tenant hardware. 3. Dedicated Host (host) — Your instance runs on a physical server with EC2 instance capacity fully dedicated to your use, an isolated server with configurations that you can control. The default tenancy in a VPC is *Default*. It means new easy to instances can be created on shared hardware devices. You can change the tenancy to *dedicated*, it will create the instances on the same hardware. If you select tenancy as *host*, your instance runs on a physical server with EC2 instance capacity fully dedicated to your use.

Answer 47

To ensure that an Elastic Load Balancer stops sending requests to instances that are de-registering or unhealthy while keeping the existing connections open, use connection draining. This enables the load balancer to complete in-flight requests made to instances that are de-registering or unhealthy. The maximum timeout value can be set between 1 and 3,600 seconds (the default is 300 seconds). When the maximum time limit is reached, the load balancer forcibly closes connections to the de-registering instance.

EC2 Flashcards

(76 cards)