freecodecamp Flashcards

1
Q

ElasticBeanstalk

Which deployment method should be used if a fast rollback is required?

A

Immutable

This creates a new set of instances and switches the load balancing.
The old servers are still present.

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2
Q

ElasticBeanstalk

What are the 6 Linux Server Configurations?

A

PUCCFS

Packages - What additional packages (nginx, redis e.g.) should be installed Usually done with “yum”

Users/Groups

Commands - Runs commands, such as staring nginx

Container Commands

Files - Creates files, for example for configs

Services - Checks the status of a service (nginx - ensureRunning: true)

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3
Q

ElasticBeanstalk

You need to get the AMI of a specific Java Version, how to do this?

A

Use the describe-platform-version command with the region and the platform-arn parameter

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4
Q

ElasticBeanstalk

Where are the configuration files stored?

A

.ebextenstions

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5
Q

ElasticBeanstalk

It takes to long to start up a service, what can be done?

A

Use a custom AMI with all needed services baked in

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6
Q

ElasticBeanstalk

What is the CLI command to swap environments?

A

eb swap [original] –destination_name [new]

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7
Q

ECS

What is an essential container?

A

Required setting, if this container fails or stops, all other container will be stopped.

A task has at least one essential container

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8
Q

ECS

How to include secrets form the Parameter store?

A

Use the Value From instead of Value in the Environment variables

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9
Q

X-Ray

What does the Service Graph show?

A

Client, front-end services (lambda, sns, ec2), back-end services (databases)

It improves view into bottlenecks and latency spikes

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10
Q

X-Ray

What is a segment, and what data does it show?

A

A segment is the service that is sending data like it’s IP, the taken request, what work has been done, if it was successful or not (and the reasons)

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11
Q

X-Ray

You know that there are failed requests, but you cannot see them in X-Ray - what could be a reason?

A

The sampling rate is too low

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12
Q

ACM

Which services can you attach a certificate to?

A

ELB
CloudFront
API Gateway
(ElasticBeanstalk through an ELB)

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13
Q

ACM

What is SSL Termination?

A

The encryption is decrypted on the ALB

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14
Q

Route53

How to connect to on-premise servers?

A

Use Route53 Resolver

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15
Q

CLI

You need to switch between Accounts while using the CLI, what can be done?

A

using the profile parameter

aws s3api list-buckets –profile admin_mark

The profile makes reference to the .credentials file

[mark]
aws_access_key=123
aws_secret_access_key=ABC
[admin_mark]
..
..
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16
Q

KMS

What are the common five KMS CLI commands

A
aws kms create-key
aws kms encrypt
aws kms decrypt
aws kms re-encrypt
aws kms enable-key-rotation
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17
Q

SQS

You have messages around 3mb and want to deliver them to SQS using the PHP SDK, how can this be done?

A

It cannot be done with the SDK for PHP.

But for Java you can use the SQS Extended Client Library for Java for messages up to 2GB.
It will put the message to S3 and send the reference to SQS.

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18
Q

Parameter Store

What are the differences between Standard and Advanced tier?

A

4kb / 8kb
10.000 params / 100.000 params
no policies / parameter policies

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19
Q

Parameter Store

What are parameter policies?

A

Forcing an update or delete on a parameter.

Especially useful for passwords.

20
Q

Parameter Store

How to create hierachy in parameters?

A

include a names structure separated by /

21
Q

DynamoDB

What is a partition and how are they created?

A

A slice of a large table group by similiar data -

They are automatically created by AWS, when more than 10GB of new data is inserted or the read/write capacity for a single partition is reached.

22
Q

DynamoDB

What are the use cases for on-demand capacity?

A
  • New project
  • unpredictable Traffic
  • align cost with usage
23
Q

DynamoDB

What are DynamoDB Transactions?

A

All-or-nothing requests across multiple tables for read (TransactGetItems) and write (TransactWriteItems) actions.

In addition to the normal read/write consumption there are two underlying requests.
One for preparing the transaction and one for committing the transaction

24
Q

DynamoDB

How does TTL work?

A

NOT given in seconds on the item, but you define a column that specifies the datetime the item should expire

25
Q

DynamoDB

I set a TTL on a column, but the data does not get deleted, what could be a reason?

A

The string representing the time is not formated in epoch time.

26
Q

DynamoDB

You want to get notified (via E-Mail) when a user gets deleted from a table, how to do this?

A

Set up DynamoDB Streams, which will call a Lambda function which can take the action

27
Q

DynamoDB

I received the ThrottlingException, what could be the reason?

A

Too many request to CreateTable, UpdateTable or DeleteTable

28
Q

DynamoDB

I received the ProvisionedThroughputError, what could be the reason?

A

Reached max. allowed provisioned capacity

29
Q

DynamoDB

What is the main advantage of a Local, compared to a Global Secondary Index?

A

You can strong consistency only with a LSI

30
Q

IAM

What is the process to get access using an WebIdentity provider?

A
  1. Authenticate with OAUth (e.g.) on the Identity Provider
  2. IP sends a JWT
  3. Use CLI or SDK to call the AssumeRoleWithWebidentity on STS, sending the credentials
  4. STS returns the temp. security credentials
31
Q

CloudFront

What specifies a Distribution?

A

A Distribution is a collection of Edge Locations (defined as “Price Class”)

  1. Type: Web / RTMP
  2. Behaviour: HTTPS redirect, Viewer access, TTL
  3. Error / Root Page
  4. Geo Restrictions
32
Q

CloudFront

What is Lamdba@Edge?

A

Using four (Viewer/Origin request & Viewer/Origin response) hooks to change the behaviour of the requests using lambda

33
Q

CloudFront

How to disallow direct access to the origin S3?

A

Use Restrict Bucket Access and (automatically) create a Origin Access Identity (OAI)

34
Q

CloudFront

How to invalidation all or single data?

A

Using a wildcard to erase all or use the filename for a single item

35
Q

CloudTrail

What is the difference between Event History and a Trail

A

EventHistory is enabled by default and stores data (visible in a GUI) for 90 days

A trail logs indefinitely in S3 and can be crawled using Athena

36
Q

CloudTrail

I created a trail but data is missing from other regions, what is the problem

A

CloudTrail can be inter-regional - but it must be set up on creation.

Note: it is not one trail, but the trail configuration is copied to other regions

37
Q

CloudFormation

What is FN::GetAttr?

A

Allows to get many attributes from a resource, such as a Security Group ID, the private IP or the Availability Zone

38
Q

CloudFormation

On what resources should you use a CreationPolicy and on which a WaitCondition?

A

CP: EC2 & ASG
WC: Everything else like an ELB

39
Q

CodeBuild

What are the phases?

A

install
pre_build
build
post_build

40
Q

Lambda

What is the (soft) limit of concurrent running functions?

A

1000

41
Q

Lambda

What are the RAM limits?

A

128mb to 3008mb

42
Q

Lambda

What ist the max. runtime, and would could be an alternative?

A

15min

Use Fargate

43
Q

Lambda

What is a (un)qualified ARN?

A

Qualified: ends with a version indicator, such as &LATEST

An unqualified just lists the function

44
Q

Lambda

What is an alias?

A

friendlier name that also references a specific version

45
Q

Lambda

What are Layers?

A

Additional code, such as libraries that are put in a zip file and attached to the function.

In unzipped state cannot exceed 250mb an there’s a limit of 5 layers