Simple Storage Service (S3) Flashcards

1
Q

Which type of S3 encryption shows as AES256

A

SSE-S3

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2
Q

Which S3 Storage class is suitable for data which is easily replaced (choose the most cost effective)

A

S3 One Zone-IA

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3
Q

Which Object class in S3 is ideal for uncertain access and low admin overhead

A

S3 Intelligent-Tiering

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4
Q

What is the cheapest S3 storage class for important data which need to be retained for long periods and is rarely accessed

A

S3 Glacier

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5
Q

Which steps are required to allow an S3 bucket to operate as a website (choose all which apply):

Install the HTTPD server files into the S3
Upload web files
Set index and error documents
Enable static web hosting
Enable versioning
Disable block public access settings
Add a bucket policy
Add an identity policy

A

Upload web files
Set index and error documents
Enable static web hosting
Disable block public access settings
Add a bucket policy

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6
Q

What S3 feature allows objects storage classes to be changed and objects deleted automatically

A

S3 Lifecycle policies

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7
Q

What is the default limit of the number of S3 buckets in an AWS account

A

100

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8
Q

How large can an object in S3 be ? and what (if any) limits are there on the number of objects in a bucket

A

Object Max = 5TB, No Object bucket limit

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9
Q

What S3 feature needs to be enabled to allow Cross-Region Replication (CRR)

A

Versioning

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10
Q

What S3 feature can be used to grant external accounts access to an S3 bucket

A

Resource Policies

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11
Q

Which type of encryption allows for role separation where an S3 Full Admin might not be able to decrypt objects

A

SSE-KMS

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12
Q

Which type of encryption is where AWS perform encryption operations but DON’T hold any keys

A

SSE-C

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13
Q

What type of encryption means AWS perform the encryption operations and handle key creation & management

A

SSE-S3

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14
Q

What feature is required to allow CRR to function

A

Versioning

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15
Q

What happens when an object is deleted in a bucket with versioning enabled

A

A delete marker is added

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16
Q

When should you use ACLs for S3

A

Never, unless you must, but AWS discourages their use

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17
Q

When should you use identity policies to manage S3 bucket access

A

When you need different identities to control different resources
When you have a preference for IAM

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18
Q

When should you use bucket policies

A

To just control S3
To allow anonymous or cross-account access

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19
Q

Can you disable bucket versioning once enabled

A

No, but you can suspend and unsuspend it

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20
Q

Which versions consume space in an S3 bucket with versioning enabled

A

All the versions

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21
Q

How do you achieve 0 cost for a bucket where you had enabled versioning

A

By deleting the bucket or by manually purging all versions

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22
Q

Does suspending bucket versioning delete old versions

A

No

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23
Q

How do you enable MFA delete on an S3 bucket

A

In versioning configuration

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24
Q

What does MFA delete mean on an S3 bucket

A

It means that MFA is required to change bucket versioning state, and to delete versions

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25
Q

What does MFA delete mean with regards to API calls to S3

A

You need to provide the serial number of the MFA thingy and the code

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26
Q

What is the minimum object size for multipart upload

A

100MB

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27
Q

What ar ethe 2 restrictions when using S3 accelerated transfer

A

No period in bucket name
Naming is DNS-compatible

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28
Q

What compliance does KMS provide

A

FIPS 140-2 Level 2
Some features have L3 compliance, but overall L2

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29
Q

Does KMS store Data Encryption Keys (DEKs)

A

No, it provides it then discards it

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30
Q

How are DEKs used

A

They are generated, then the plaintext version can be used to encrypt and is then discarded, then an encrypted version is kept. It is encrypted with the KMS key that generated it. You store the encrypted key with the data

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31
Q

how are KMS keys handled by default with regards to regions

A

By default, they ar erestricted to one region and never leave it

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32
Q

Are buckets ever encrypted

A

No, the objects within it are.

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33
Q

What is SSE-C

A

Customer manages the keys, S3 does the encrypting

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34
Q

What is SSE-S3

A

S3 manages the keys and encryption

35
Q

What is SSE-KMS

A

Same as SSE-S3, but with KMS key

36
Q

What algorithm is used by SSE-S3

A

AES-256

37
Q

What is default encryption for S3 buckets

A

It only applies to objects for which encryption is not specified

38
Q

What is an advantage of SSE-KMS

A

Users that have permissions for S3 can only access objects if they also have permissions for the key

39
Q

What can you assume when S3 responds with 200

A

Data has been stored durably

40
Q

When should S3 standard be used

A

For frequently accessed data which is important and non replaceable

41
Q

When should S3 standard Infrequent Access be used

A

For long-lived data, which is important, but for which access is infrequent

42
Q

When should S3 One Zone IA be used

A

For long-lived data which is non-critical and replaceable and where access is infrequent

43
Q

When should S3 Glacier instant be used

A

For long-lived data, accessed once per quarter with millisecond access. You still have instant access

44
Q

When should S3 Glacier flexible be used (formerly S3 Glacier)

A

Use for archival data where frequent or real-time access is not needed. It takes minutes for retrieval.
First byte latency is minutes or hours (different possible speeds)

45
Q

Where are objects retrieved from S3 glacier stored

A

Temporarily stored in S3 infrequent access

46
Q

When should you used S3 Glacier Deep Archive

A

Use for archival data that rarely, if ever, needs to be accessed, It takes hours or days for retrieval (Legal or regulation data storage)

47
Q

When should you use AWS intelligent-tiering

A

Use for long-lived data with changing or unknown access patterns

48
Q

Which tiers are optional in AWS intelligent-tiering

A

The glacier ones with long access times

49
Q

What can’t you use as a trigger for S3 lifecycle

A

Accesses, you should use Intelligent Tiering instead

50
Q

What transition can’t be made with Lifecycle configuration for S3

A

One-zone IA into glacier instant retrieval

51
Q

What should you be careful with when doing lifecycle configurations

A

Small objects due to minimum billable size for some tiers

52
Q

What is the minimum length of time an objects needs to be in S3 standard before moving to IA or OZ IA with lifecycle configurations

A

30 days, however you could upload directly to them, it’s just not ok if they are first in standard. You can also do it manyually, you just won’t be able to do it using lifecycle config

53
Q

What is the minimum length of time an object needs to be in IA or OZ IA before going to the glacier classes

A

30 days

54
Q

What does Replication Time Control do

A

It adds 15 minutes replication SLA, otherwise it is a best-efforts process. It adds a guaranteed level of predictability and monitoring

55
Q

What is replication

A

Replicated from source to destination bucket

56
Q

What are the 2 types of replication

A

Cross-region replication
Same-region replication

57
Q

Is replication retroactive

A

No

58
Q

What is needed to activate replication

A

Versioning needs to be enabled

59
Q

Is replication one-way

A

Yes

60
Q

What encryptions types can be enabled by S3 replication

A

SSE-S3, SSE-KMS. It cannot handle SSE-C

61
Q

What is a permissions restriction when doing replication

A

The source bucket owner needs permissions to objects

62
Q

What is not replicated in S3 buckets even when replication is enabled

A

System events (changes made by lifecycle management), and Glacier or Glacier Deep Archive

63
Q

What is the default deletion behavior with S3 replication

A

Deletes (delete markers) are not replicated, but it can be enabled

64
Q

What are the reasons to use Same Region Replication

A
  • To aggregate logs from different sources in a single location
  • To synchronise prod & test data
  • For resilience while maintaining strict sovereignty (keeping data in a specific country)
65
Q

What are the reasons to use Cross-Region Replication

A
  • Global resilience improvements
  • Latency reduction
66
Q

What are S3 presigned urls used for

A

To give a person or an application access to objects inside an S3 bucket using credentials in a safe & secure way

67
Q

How do you use presigned urls

A

You create an IAM user for an application, then the app asks for a presigned url of this IAM account.

68
Q

What is a common use of Presigned URLs

A

To offload media into S3, or as a part of serverless architecture

69
Q

Can you create a presigned url for an object you do not have access to

A

Yes, but the presigned url also won’t have access

70
Q

What time point is referenced when using a presigned url

A

The permissions at the current moment of the generating identity are used

71
Q

What could an access denied mean when using a presigned url

A

The the generating ID never had access, or does not have access right now

72
Q

Should you use a URL generated based on a role

A

No, since the URL will stop working when the temporary credentials expire, which usually happens before the url expires

73
Q

What is S3 select and Glacier Select used for

A

To retrieve part of an object instead of the entire thing using SQL-like statements

74
Q

What is an advantage of S3 select

A

It is pre-filtering that helps you save data transfer fees

75
Q

How much can you save with S3 select

A

Up to 400% faster and 80% cheaper

76
Q

What are the 2 modes for Retention Period of Object Lock

A

Compliance mode
Governance mode

77
Q

What is the difference between compliance mode and governance mode

A

Compliance mode can’t be changed

78
Q

Can an account root user change an object in compliance mode

A

No

79
Q

What do you need to modify an object locked in governance mode

A

The S3::BypassGovernanceRetention permission
Also need x-amz-bypas-governance-retention:true in header of request, however this is default in console ui

80
Q

What is legal hold for object lock

A

It is binary, you can’t delete or change until it is removed

81
Q

What permission is required to add or remove legal hold

A

S3:PutObjectLegalHold

82
Q

What is a use case for legal hold

A

Prevent accidental deletion of critical object versions

83
Q

Can you use retention period with legal hold

A

Yes
You can use many with overlap