Cost Optimization - Compute

Question 1

EC2 - Characteristics

Answer 1

• In general the charges are per hour or second while the instance is running
• Pricing also depends on purchase option selected, EBS storage provisioned, data transfer in and out of the service, EIP addresses, and other features
• CloudWatch Alarms actions can automatically stop, terminate, reboot or recover instances

Question 2

EC2 - Placement groups

Answer 2

• Cluster: packs instances close together inside an AZ. This strategy enables workloads to achieve the lowest latency and highest packet-per-second network performance
• Partition: spreads instances across different logical partitions. Used by large distributed and replicated workloads such as Hadoop, Cassandra, and Kafka
• Spread: places a small group of instances across distinct underlying hardware

Question 3

EC2 - On-Demand

Answer 3

• Pay by the second for the instances that you launch. Have full control over its lifecycle
• Great when you need uninterrupted compute. One of the most expensive options

Question 4

EC2 - Savings Plans

Answer 4

• You make a commitment to a consistent usage, in USD per hour, for a term of 1 or 3 years
• Offers more flexibility than reserved instances but it’s not cheaper than them
• Unlike Reserved Instances, it does not reserve capacity. You commit to an amount of compute usage
• Useful for mixed EC2 instances, Fargate, and Lambda

Question 5

EC2 - Savings Plans types

Answer 5

• Compute Savings Plans:
• Provide savings up to 66 percent off On-Demand
• This discount apply regardless of Region, instance family, instance size, OS, and tenancy
• EC2 Instance Savings Plans:
• Provide savings up to 72 percent off On-Demand, in exchange for a commitment to a specific instance family and a Region
• This discount apply regardless of instance size, OS, and tenancy

Question 6

EC2 - Reserved instances 1

Answer 6

• You make a commitment to a consistent instance configuration of On Demand instances, including instance type and Region, for a term of 1 or 3 years
• Up to 72% saving compared to On Demand instances
• Upfront payment can be: all, partial, or none

Question 7

EC2 - Reserved instances 2

Answer 7

• Have two types:
• Standard: offers more discount than Convertible, up to 66% compared to On-Demand, but can’t be exchanged for another instance
• Convertible: offers discount, up to 56% compared to On-Demand. Can be exchanged for another instance
• There’s instance size flexibility only on Linux VMs. For example, a large reserved instance can be used as two medium reserved instances

Question 8

EC2 - Reserved Instances: scopes

Answer 8

• Regional Reserved Instance:
• A reserved instance for a Region
• Doesn’t reserve capacity
• AZ and instance size flexibility are permitted
• Zonal Reserved Instance:
• A reserved instance for a specific AZ
• Reserves capacity in a specific AZ
• No AZ and instance size flexibility

Question 9

EC2 - Spot instances

Answer 9

• It’s an instance that uses spare EC2 capacity
• Spot price is the hourly price for a Spot instance. The Spot price is set by EC2
• It runs whenever capacity is available and your bid exceeds the Spot price
• Up to 90% savings compared to On Demand instances

Question 10

EC2 - Spot instances types

Answer 10

• Spot instance
• Spot fleets: set of Spot Instances and optionally On Demand Instances that are launched under a specific criteria
• Spot blocks: several VMs that are guaranteed to run for a specific number of hours

Question 11

EC2 - Spot instances termination

Answer 11

• When you lose a post bid: you receive a 2 minute warning. Can monitor those warnings with CloudWatch
• These instances can be terminated (no charges applied), hibernated (charges applied for EBS storage and memory) or stopped (charges applied for EBS storage and memory)

Question 12

EC2 - Dedicated hosts

Answer 12

• Pay for a physical host fully dedicated to running your instances
• Useful for existing per-socket, per-core, or per-VM software licenses
• Have visibility and control over how instances are placed on the server (number of sockets or physical cores)

Question 13

EC2 - Dedicated instances

Answer 13

• Pay, by the hour, for instances that run on single-tenant hardware. Cannot bring your own license
• Don’t have visibility and control over how instances are placed on the server (number of sockets or physical cores)

Question 14

EC2 - Capacity reservations

Answer 14

• It’s an On Demand instance with reserved compute capacity in a specific AZ for any duration
• It allows to ensure that always have access to EC2 capacity when you need it, for as long as you need it
• Doesn’t need a commitment as Reserved Instances or Savings Plans
• Doesn’t provide billing discount. To receive a discount can combine it with Savings Plans or Regional Reserved Instances

Question 15

EC2 - Instance types considerations

Answer 15

• Consider cost of every instance type. For example m5.2xlarge is twice as expensive as m5.xlarge
• If you need the highest I/O performance an instance store volume is better than an EBS volume. An instance store provides temporary block-level storage. It’s ideal to store temporary information that changes frequently
• Consider the usage of EBS-optimized instances. Fully use the IOPS provisioned on an EBS volume

Question 16

EC2 - Instance types families

Answer 16

• General purpose (T, M, A1 instances): provide a balance of compute, memory and networking resources
• Compute optimized (C instances): for applications that need high performance processors
• Memory optimized (R, X2, X1, z1 instances): deliver performance for workloads that process large data sets in memory
• Accelerated computing (P, DL, Trn, Inf, G, F, VT): use hardware accelerators, or co-processors, to perform more efficiently than CPUs
• Storage optimized (Img, Is, I, D, H): designed for workloads that require high sequential access to large data sets

Question 17

EC2 - Instance considerations

Answer 17

• Fixed performance instances are more expensive than burstable. Must indicate the used CPU capacity
• Burstable performance instances:
• Provide a baseline level of CPU with the ability to burst above that baseline
• If the CPU isn’t being used, tokens are backed on a token bucket. When you need CPU above baseline you can cash in those tokens
• Useful for intermittent operations
• A new public IPv4 address of an instance is reassigned when its stopped and started again

Question 18

EC2 - Enhanced Networking

Answer 18

• It has two mechanisms:
• Elastic Network Adapter (ENA)
• Intel 82599 Virtual Function Interface (VF)
• Elastic Fabric Adapter (EFA):
• It’s an ENA with added capabilities
• It’s a network device that you can attach to an EC2 instance to accelerate HPC and ML applications

Question 19

EC2 - Burstable performance instance modes

Answer 19

• Standard: if you used all tokens you will be throttled back to the baseline
• Unlimited: if you used all tokens you will be charged on-demand for the extra power

Question 20

EC2 - Instances right sizing tools

Answer 20

• CloudWatch to monitor resources usage
• Cost Explorer: use optimization recommendations
• Trusted Advisor: use best practices on cost reductions

Question 21

EC2 - Right sizing tips

Answer 21

• Avoid conversions to older generations
• Before moving to a new instance:
• Monitor CPU, memory
• Monitor network throughput
• Consider if you are using ephemeral storage. Might lose it if you terminate that instance

Question 22

Serverless

Answer 22

• Lowers TCO and makes your app more agile
• Provides flexibility and automatic scaling
• Offers high availability and fault tolerance
• Platform:
• Compute: Lambda, Fargate
• Storage: S3
• Database: DynamoDB, Aurora
• API Proxy: API Gateway
• Integration: SNS, SQS