EC2 Fundamentals Flashcards
Elastic Compute Cloud Services
- rent virtual machines (EC2)
- store data on virtual drives (EBS)
- distribute load across machines (ELB)
- scale services using auto scaling group (ASG)
EC2 Configuration
- OS, computer power & cores (CPU)
- RAM
- storage
- EBS & EFS (network attached)
- hardware (EC2 instance store)
- Security Groups - firewall
- regulate access to ports
- authorized IP ranges
- control of inbound AND outbound
- can be attached to multiple instances
- locked down to a specific region/vpc combination
- only contain ‘allow’ rules
- by default all inbound traffic is blocked
- by default all outbound traffic is authorized
- can reference by IP or security group
- if you app hangs, then it’s a security group issue
- if your app gives ‘connection refused’ then it’s an application error
- bootstrap script - configure at first launch: ec2 user data
EC2 User Data Script
- can bootstrap our instances using an EC2 user data script
- install updates, software, etc
- only ran once at startup
EC2 Instance Types
When does EC2 public IP change?
- public ip will change if you start/stop instance
- private ip will not change
Common EC2 ports
- 22 - SSH
- 21 - FTP
- 22 SFTP (Secure file transfer protocol) uses ssh
- 80 - HTTP
- 443 - HTTPS
- 3389 - RDP (remote desktop protocol) log into windows instance
EC2 reserved purchase option
- long workloads
- convertible reserved instances
- can change the ec2 instance type, family, os
- up to 72% discount compared to on-demand
- reserve instance type, region, os
- payment options
- up front, partial upfront, all upfront
- scope - regional or zonal
- recommended for steady state usage apps (think database)
- can buy and sell in the reserved instance marketplace
Ec2 on demand purchase option
on-demand instances - short workload, predictable, pay by second
Ec2 saving plan purchase option
- commit to certain types of usage (10%/hr for the next 1 or 3 years)
- additional usage is at the ‘on-demand’ price
- locked into a specific instance family and region (M5 in us-east-2)
- flexible across instance size (m5.xlarge, m5.2xlarge) and os (linux,windows)
Ec2 spot instances purchase option
- most cost-effective
- good for batch jobs, distributed workloads, data analysis
- not suitable for critical jobs and databases
- short workloads, cheap, less reliable
Ec2 dedicated hosts purchase option
- allows you to address compliance requirements and use existing server bound software licenses
- can pay as ‘on demand’ or reserved (1 or 3 years)
- most expensive
- book an entire physical server and control instance placement
Ec2 dedicated instances purchase option
- no other customers will share your hardware
- no control over instance placement
burstable performance instances
Burstable performance instances, which are T3, T3a, and T2 instances, are designed to provide a baseline level of CPU performance with the ability to burst to a higher level when required by your workload. Burstable performance instances are the only instance types that use credits for CPU usage.
EC2 Basic Monitoring
5 minute granularity (detailed is 1 min)
enabled by default using launch templates and through aws console when creating a launch configuration
EC2 detailed monitoring
1 min granularity
enabled by default when creating a launch configuration with the aws cli or sdk
when a spot instance is interrupted
You can specify that Amazon EC2 should do one of the following when it interrupts a Spot Instance:
Stop the Spot Instance
Hibernate the Spot Instance
Terminate the Spot Instance
The default is to terminate Spot Instances when they are interrupted.
Regional vs Zonal reserved instances
EC2 auto scaling
A volume is attached to a new instance when it is added. Amazon EC2 Auto Scaling doesn’t automatically add a volume when the existing one is approaching capacity. You can use the EC2 API to add a volume to an existing instance.
regional constructs. span AZs but not regions
You don’t have to use ELB to use Auto Scaling. You can use the EC2 health check to identify and replace unhealthy instances.
