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All you need to know about EC2 instance

aziz.amghar
・4 min read

EC2 instance is an amazon virtual machine, there are many EC2 instance types, find below the main ones:

- R: apps that need a lot of RAM -in memory caches
- C: apps that need good CPU – compute / databases
- M: apps that are balanced (think medium) – general / web app
- I: apps that need good local I/O (instance storage) – databases.
- G: apps that need a GPU – video rendering / machine learning.
- T2/T3: burstable instances (up to a capacity)
- T2/T3: unlimited burst

Pricing models:

  • On Demand: pay per hour or second with no commitment, it is low cost, flexible and used for short term, dev/testing and you have a predictible price.
  • Reserved: you get a significant discount (1y-3y), it is used for apps that have steady state and that require capacity:
    • Convertible reserved instances: long workloads with flexible instances.
    • Scheduled reserved instances, example: every Thu between 3 and 6 pm.
  • Spot: you bid whatever price you want for instance, it is used for apps that have flexible start & end times.
  • Dedicated instances: no other customers will share your hardware, billing is based on instance.
  • Dedicated hosts: you book an entire physical server, for regulatory (no multi-tenant support), great for licensing,

Important: for prod environnement
Termination protection is turned off by default, you must turn it on.

EBS: 5 different types of EBS storage:

  • General purpose SSD
  • Provisionned iops SSD
  • Throughput optimized HDD
  • Cold HDD (lowest )
  • EBS magnetic

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AMI Types (EBS vs instance store):

  • For EBS volumes: the root device for an instance launched from the AMI is an EBS volume created from an EBS snapshot.
  • For Instance store volumes: the root device for instance launched from the AMI is an instance store volume created from a template stored in S3.
  • Instance store volume is an Ephemeral storage: if stopped, you will lose all your data.
  • Instance store is physically attached to the machine (EBS is a network drive).
  • Instance Store Pros:
    • Better I/O perofrmance
    • Good for buffer / cache / scratch data / temporary content.
  • Instance Store Cons:
    • On stop or termination, the instance store is lost.
    • You cant resize the instance store
    • Backups must be operated by the user.
  • EBS RAID Options (do it on OS not AWS):
    • RAID0: increase performance (lots of iops), but more risk (if 1 disk fail, data lost).
    • RAID1: increase fault tolerance (mirroring).
    • RAID5 (not recommanded for EBS)
    • RAID6 (not recommanded for EBS)

Elastic Network Interface vs Enhanced Networking vs Elastic Fabric Adapter:

  • ENI: elastic network interface, virtual network card
    • For basic networking, create a management network, use a network appliance in your VPC..
    • Low cost
  • EN: Enhanced networking: uses single root I/O virtualization, there is 2 types:
    • ENA elastic network adapter: 100Gbps
    • VF virtual function: 10Gbps
  • Elastic Fabric Adapter: for machine learning or high performing computing (HPC) or OS bypass.

EBS encryption:

  • Data in transit between an instance and an encrypted volume is also encrypted
  • Encryption is supported on all Amazon EBS volume types

EFS: Elastic File System

  • It grows automatically, great for file server or sharing data between EC2 instances
  • You pay for what you use
  • EFS support NFSv4 protocol
  • You only pay for the storage you use
  • Can scale up to the petabytes
  • Can support 1000s of concurrent NFS connections
  • Data is stored across multiple AZs within a region
  • Read After write consistency

Amazon FSx for Windows and for Lustre:

  • FSx for windows: built on windows server, use SMB and supports AD users, DFS (Distributed File System).. . Centralized storage for windows, Sharepoint, IIS or other native app for microsoft:
    • Can be accessed from your on-premise infrastructure
    • Can be configured to be MultiAZ (HA)
    • Data is backed up daily to S3
  • EFS: is linux only, use it if you need distribution..
  • FSx for Lustre: for linux, if you process large data sets, millions of IOPS, machine learning, High Performance Computing (HPC), video processing, electronic design automation, financial modeling.

EC2 Placement Groups:

  • Clustered placement group: within a single Availability Zone
    • Pros: Low Network Latency / High network throughput
    • Cons: if the rack fails, all instances fails at the same time.
    • Use case: Big data job that needs to complete fast.
  • Spread placement group: individual instances placed in different hardware (rack..), for single instance
    • Pros:
      • Can span across AZs
      • Reduce risk of simultaneous failure
      • EC2 instances are on different physical hardware
    • Cons:
      • Limited to 7 instances per AZ per placement group
    • Use case:
      • App that needs to maximize high availability.
      • Critical apps where each instance must be isolated from failure from each other
    • Partitioned Placement Group: think multiple instances in partition group.
      • Up to 7 partitions per AZ
      • Up to 100s of EC2 instances
      • The instances in a partition do not share racks with the instances in the other partitions.
      • A partition failure can affect many EC2 but won’t affect other partitions.
      • EC2 instances get access to the partition: information as metadata
      • Use case: HDFS, HBase, Cassandra, Kafka

EC2 Hibernate.

  • The in-memory (RAM) state preserved.
  • The instance boot is much faster (os is not stopped/restarted)
  • Under the hood:the RAM state is written to a file in the root EBS volume
  • The root EBS volume must be encrypted
  • Supported instance families: C, M and R.
  • Instance RAM size must be less than 150GB
  • Available for OnDemand and Reserved Instances.
  • An instance cannot be hibernated more than 60days
  • Use cases:
    • long running processing
    • saving the RAM state
    • services that take time to initialize.

EC2 Best practices
Security

  • Manage access to AWS resources using IAM roles.
  • Implement the least permissive rules for your security group (Firewall).
  • Patch, update and secure regularly the operating system and applications on your EC2 instance.

Storage

  • Use separate Amazon EBS volumes for the operating system and data.
  • Ensure that the data volume persists after instance termination.
  • Encrypt EBS volumes and snapshots.

Resource management

  • Use instance metadata and custom resource tags to track and identify your AWS resources.
  • View your current limits for Amazon EC2 and plan in advance the request of any limit increases.

Backup and recovery

  • Backup periodically your EBS volumes using snapshots.
  • Create an Amazon Machine Image (AMI) from your instance to save the configuration as a template if needed for future installation.
  • Deploy critical components of applications across multiple AZs.
  • Monitor and respond to events.
  • Test regularly the process of recovering your instances and Amazon EBS volumes if they fail.

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