Compute 101:

Basic computer components:

OS (linux, osx)
CPU (processing power, brains)
Hard Drive (local storage)
Network card (internet access, ethernet or wifi)
Firewall (security, help block unauthorized things from accessing your computer)
RAM (short term memory, data loaded into this memory before processed)

Elastic Compute Cloud (EC2)

💻 EC2 = basic computer, scalable (vertically and horizontally), config security and networking, and manage storage, elastic.

Purchase instances on demand, or reserved basis (cheaper but locked into a longer term contract for the instance duration)
Spot instances = only pay for instance when price is at or below a price threshold — gives you discount for unused instances (charged by the minute)
Instance Types: general purpose, compute optimized, accelerated computing, memory optimized, and storage optimized.
EBS optimized = option for higher IOPS performance
AMI type = which OS you want with diff prices for diff OS’s / versions
Data transfer = charged for how much data moving in/out of the instance
Region = where the instance is provisioned (priced differently per region)

Amazon Machine Image (AMI) = OS = pre configured package required to launch EC2 instance.
AMI is like a template with the desired server environment (and can spin up as many instances as you want/need from any template AMI)
Community AMIs = free to use, usually just the OS
AWS marketplace AMIs = pay to use, comes packaged with additional software you want to use usually
My AMIs = custom created AMIs
AMI components: 1. Root Volume template (OS and software), 2. Launch Permissions, 3. Block device mapping (EBS or hard drive mapping for storage)
Can add storage to EC2 instances using Elastic Block Store (EBS)
EBS = storage volume for instances, like a hard drive. Highly available, must be in the same AZ as the instance. Can persist past the life of the instance.

SGs = allow or deny traffic
SGs are on the instance level.
Different from NACLs
SGs are like virtual firewalls that controls the traffic for instances. When you launch an instance you associate one or more SGs with the instance.
SGs start with all deny traffic rules, and add rules to allow traffic.
Remember, NACLs are at the subnet level.

1. Create key pair (.pem) when launching instance and save to your local machine.

2. Run ‘chmod 400 sshkeypair.pem’ to change permissions on a mac

3. Connect to instance using DNS name or public IP address: run command ‘ssh -i “sshkeypair.pem” ec2-user@ec2–54–196–0–138.compute-1.amazonaws.com’

Now you are connected to instance on the CLI

Once connected you will see the private IP on the command line.