Mehmet Sat | Personal Blog

Amazon EC2

· mehmet sat
  • EC2 is like a VM, hosted in AWS instead of your own data center
    • Select the capacity you need right now. Grow and shrink when you need
    • Pay for what you use

EC2 types and Pricing options

  • On-Demand Instances

    • Pay by the hour or the second
    • Great for flexibility, but expensive

  • Spot Instances

    • Purchase unused capacity at a discount of up to %90
    • Prices fluctuate with supply and demand
    • Great for applications with flexible start and times

  • Reserved Instances

    • Reserved capacity for 1 or 3 years
    • Up to %72 discount on the hourly charge
    • Great if you have known, fixed requirements

  • Dedicated Instances

    • A physical EC2 server dedicated for your use
    • Great if you have server-bound licenses to reuse or compliance requirements

    AWS CLI

  • Least Privilege: Always give your users the minimum amount of access required to do their job

  • Use Groups for permissions: Create IAM groups and assign your users to groups. Group permissions are assigned using IAM Policy documents. Your users will automatically inherit the permissions of the group

  • Secret Access Key : You will see this once. Don’t lose it. You will need to run aws configure again.

IAM Roles

  • The preferred option from the security perspective
  • Roles allow you to provide access without the use of access key IDs and secret access keys
  • You can update a policy and see the immediate effect
  • You can attach and detach roles to your running EC2 instances without having to stop or terminate these instances

Security Groups

  • Changes to security groups take effect immediately
  • You can have any number of instances within a security group
  • you can have multiple security groups attached to EC2 instances
  • All inbound traffic is blocked by default
  • All outbound traffic is allowed

Bootstrap Scripts

  • A bootstrap script is a script that runs when the instance first runs.
  • It passes user data to the EC2 instance and can be used to install applications(like web-servers and databases), as well as do updates and more

Data vs Metadata

  • User data are simply bootstrap scripts
  • Metadata is data about your EC2 instances
  • You can use bootstrap scripts to access metadata

Networking with EC2

  • Elastic Network Interfaces (ENI):
    • It is for basic networking comes default with EC2.
    • Perhaps you need separate management network from your production network or a separate logging network, and you need to do this at a low cost: Use multiple ENIs for each EC2 instance
  • Enhanced Networking:
    • When you need speeds between 10Gbps and 100Gbps
    • Anywhere you need reliable, high throughput
  • Elastic Fabric Adapter:
    • When you need to accelerate High Performance Computing(HPC) and machine learning applications or if you need to do an OS-bypass.
    • If you see a scenario question mentioning HPC or ML and asking what network adapter you want choose EFA

Placement Groups

  • Cluster Placement Groups

    • Low network latency, high throughput (In the same AZ)

  • Spread Placement Groups

    • Individual critical EC2 instances to separate them into different regions

  • Partition Placement Groups

    • Multiple EC2 instances: HDFS, HBase, and Cassandra

  • A cluster placement group cant span multiple AZs, whereas a spread placement group and partition placement group can

  • Only certain types of instances can be launched in a placement group: Compute optimized, GPU, memory optimized, storage optimized

  • AWS recommends homogenous instances within cluster placement groups

  • You can’t merge placement groups

  • You can move an existing EC2 instance into a placement group if it is in stopped state.

  • You can move or remove an instance using the AWS CLI or an AWS SDK, but you cannot do it via the console yet

Dedicated Hosts

  • It is important for licensing requirements
  • An Amazon EC2 dedicated host is a physical server with EC2 instance capacity fully dedicated to your use. Dedicated Hosts allow you to use your existing per-socket, per-core, or per-VM software licenses e.g. Windows Server, Microsoft SQL Server, and SUSE Linux Enterprise Server

Spot Instances and Spot Fleet

  • Spot Instances save up to 90% of the cost of On-Demand Instances
  • You can block Spot Instances from terminating by using Spot Block
  • Useful for any type of computing where you don’t need persistent storage
  • A Spot Fleet is a collection of Spot Instances and , optionally On Demand Instances