Compute Flashcards
What are the types of AMIs?
From AWS
Marketplace
Own AMIs
Shared AMIs
What is affected by the instance type?
Virtualization types (PV / HVM) CPU (Number and clock speed) Networking Storage Instance Limits
What are the instance classes?
General Purpose (T2, M4) Compute Optimized (C4) Memory-Optimized (X1, R4) Storage-Optimized (I3, D2) Accelerated Computing (P2, G2, F1)
How do the two virtualization types differ?
HVM (Hardware Virtual Machine) allowes advanced networking, because it runs as if it was on dedicated hardware.
Windows instances can only be on HVM
If an instance has Instance Store what states can it have?
It only can be running or terminated (not stopped)
Why use dedicated hosts?
It the use case depends on licenses that require not shared hardware
What is the advantage of a dedicated instance?
There is no other user on that uses the hardware
Can every instance type support Instance Storage?
No
How can MetaData be accessed?
It can be accessed on 169.254.169.254
What can be tracked in CloudWatch?
CPU (usage and credits), Disk, Network
What two tools are present for estimating costs?
AWS Simple Monthly Calculator
AWS Total Cost of Ownership Calculator
What are the advantages of Placement Groups?
Low network latency or/and high network throughput
How to configure EC2 for ECS?
Install the ECS Agent on the instance (ECS optimized AMIs already have the agent installed)
The instance needs the appropriate IAM role
What is the process to deploy a cluster?
- Define a task
- Define the service
- Create the cluster
- Create the stack
Structure and Limit of Elastic Beanstalk deployments
To deploy: Upload source bundle
Limits: Zip/WAR file smaller than 512 MB
What roles are created in an Elastic Beanstalk deployment?
Service Role: To access other cloud services
Instance Profile: Logs to S3 and other specific tasks
What needs to be defined for a lambda function?
Memory
Max. execution time
IAM role
Handler name
How are Lambda functions invoked?
Push event model: directly call the function
Pull event model: poll the event source and invoke function if needed
Direct invocation model: synchronously called and answers immediately.
Which of these situations typically require data migration for the root volume of an instance store-backed instance?
Scaling up means to increase the size of the instances, and with instance store-backed instances a migration is necessary
What does HVM stand for?
HVM does stand for Hardware Virtual Machine.
Which of the following is not an EC2 instance family?
Dense Storage is not an EC2 family, it is an EC2 instance type of the Storage Optimized family.
Which of these processes need to be suspended when updating an Auto Scaling Group to avoid issues?
Launch
Terminate
What is the advantage of HVM against PV?
Runs as if on bear metal server and therefore can use all hardware features
What is bootstrapping an instance - and what would be an Alternative?
Creating resources after launch using the user-date, CloudFormations cfn-update or an Configuration Management Software like Chef.
Alternatively all resources can be included in the AMI
Which services support Container Based deployments?
OpsWorks Elastic Beanstalk ECS CodeDeploy or using a 3rd party service
What does the Error Message: InsufficientInstanceCapacity mean?
AWS cannot provide enough instances of the desired type
What is the max. capacity of an instance store volume?
10GB
What happens (per default) to the EBS volumes if a EC2 instance gets terminated?
Root volume will be terminated as well.
Additional volumes will remain
What is the difference between Dedicated Instance and Dedicated Hosts?
Both use dedicated physical servers.
On the D. Host you have visibility to sockets, cores and the host ID.
You can target the launch of an instances’ placement.
This is mainly used for licensing reasons (license per core etc.)
What is EC2 Instance Recovery
In combination with CloudWatch Alarms and EBS can a failed EC2 instances be “rebooted” with the same:
- Instance ID
- IP-Addresses
- EBS volumes
ASG: What is the difference between Launch Configuration and Launch Template?
The Template is newer and has more options and is close to CloudFormation than the Launch Configuration being close to launching an EC2 instance
Which issues will cause an EC2 instance status check to fail?
Failed system status checks
Incorrect startup configuration
Exhausted memory
Corrupted file system
Incompatible kernel
What information do you need to provide Amazon to allow them to pre-warm the Elastic Load Balancer?
The total size of the request/response you will be expecting
The expected request rate per second
The start and end dates of the expected flash traffic
What could be reasons for an instance not launching on an Auto Scaling Group?
- Key Pair or Security Group does not exits
- Instance Type is not supported
- Invalid EBS mapping
- Trying to attach an EBS Volume to an instance store AMI
What feature only relates to Spread Placement Groups?
The placement group can only have 7 running instances per Availability Zone
What is the “t2 unlimited” option?
Can give burst options of CPU power beyond normal CPU credit bursting.
Comes at a addtional price
AutoScaling: What should be done if there seems to be an error with the instances and someone needs to chek it out?
Temp. suspend the scaling pricess (administrative suspension)
SQS: How to guarantee the order of the items and that a message appears only once?
Use the FIFO Queue Logic
SQS: Does Amazon SQS support message metadata?
Yes. An Amazon SQS message can contain up to 10 metadata attributes. You can use message attributes to separate the body of a message from the metadata that describes it.
SQS: What is Amazon SQS long polling?
While the regular short polling returns immediately, even if the message queue being polled is empty, long polling doesn’t return a response until a message arrives in the message queue, or the long poll times out.
Long polling makes it inexpensive to retrieve messages from your Amazon SQS queue as soon as the messages are available.
SQS: Can I delete all messages in a message queue without deleting the message queue itself?
Yes. You can delete all messages in an Amazon SQS message queue using the PurgeQueue action
SQS: Can I convert my existing standard queue to a FIFO queue?
No. You must choose the queue type when you create it. However, it is possible to move to a FIFO queue
What is the InsufficientInstanceCapacity error?
AWS does not have enough on-demand instances
What are Change sets?
Change sets allow you to preview how proposed changes to a stack might impact your running resources. For example, whether your changes will delete or replace any critical resources
CloudFormation:
How to create a multi region / multi account infrastructure?
Create an AWS CloudFormation template in a single account that defines custom resources to launch nested stacks into the other accounts and regions
EC2: What is an “Elastic Interface Accelerator”?
Elastic Inference provides cost efficient hardware acceleration for deep learning inference for all EC2 instance types, at a fraction of the cost of standalone GPU instances.
EC2: Can you use every instance type for scheduled isntances?
No, only C3, C4, M4 and R3 (Linux and Windows)
EC2: What is capacity reservation?
When you create a Capacity Reservation, we reserve the specified capacity for your use. The reserved capacity is charged at the selected instance type’s On-Demand rate whether an instance is running in it or not
What are the three parts included in an AMI?
- Template, for the instance (OS, applications etc.)
- Launch permissions
- Block Device Mapping
How to include more than 16kb in the user data?
Link more content in S3 e.g.
What is the AWS Service Catalog?
Portfolio of approved AWS products that the users can access to
Lambda: Why could a function be slow running?
The function is container based, AWS lets the container run as long as the function is called regularly. If not the container needs to spin up first.
Lambda: What happens when executing a function fails?
The functioned will be called three times. If wanted the failed request can be forwarded to a dead letter queue.
What is Lightsail?
Easily launch a VPC with a basic set of applications such as Wordpress on a LAMP stack
Only for Linux.
What is AWS Batch?
Enables developers to run hundreds of batch computing jobs
EC2: What needs to be done to change the instance size?
Stop the instance
Restart with the new instance size
Batch: What can be specified for the vCPUs?
min./max. and desired vCPUs
Where to find the current and estimated costs of the month?
In the My Billing Dashboard
What is the way to copy an AMI to another region?
Use the CopyImage API
How are on-demand instances limited?
By the families vCPU Limits
Which of the following is the top cost-saving benefit of using ECS instead of EC2?
Better memory utilization
What are the valid Spot Instance durations?
f 1, 2, 3, 4, 5, or 6 hours. After that, the
instance terminates.
What’s the minimum yearly required utilization for a scheduled instance?
1200 hours
What is the SBE Instance Type?
Comes from a SnowballEdge
