Notes on AWS, Big Data, Machine Learning and Leadership: AWS EC2

Wednesday, 14 March 2018

AWS EC2

Virtualization Types

Paravirtual (PV)
- Boot with special boot loader: PV-GRUB
- Can run on hardware without any support for virtualization
- Cannot take advantage of hardware extentions for virtualization (e.g. new Intel processors)
- Historically better performance than HVM but not anymore
  - HVM can run PV drivers ("PV on HVM")
  - HVM can use hardware extensions for virtualization
Hardware Virtual Machine (HVM)
- Presented with full set of virtualized devices
- Boot by executing MBR of root block device
- OS not modifed
- May use special PV drivers for better performance ("PV on HVM")
- Can use hardware extensions (e.g. Intel-VT)
- Newer instance types run on HVM only

Launch Template

Configuration parameters for EC2 instance
Similar to Launch Configuration
Easier to manually launch instances
Multiple versions available
Settings
- AMI
- Network Interfaces
- Storage
- Security Groups

Tenancy

Shared (default)
Dedicated Instance (single tenant)
Dedicated Host (physical machine)
- Can run multiple EC2 instances on it

vCPU

Unit of compute power
1 Hyperthreaded core (each core usually has 2 vCPU)
- Except for m3, t2

EC2 Status Checks

System - repair requires AWS involvement
- Reasons
  - Loss of network connectivity
  - Loss of power
  - Physical host HW/SW issues
- Automatic recovery (CloudWatch EC2 Actions)
  - Create CloudWatch alarm with EC2 action - recover (user must have CW/EC2 permissions)
Instance - typically customer fault
- Reasons
  - System status failure
  - Incorrect filesystem
  - Incorrect kernel
  - Wrong networking or startup configuration
  - Memory leak

Instance Console Output

Buffered - most recent 64KB stored for at least 1h
Linux: exact console output
Windows: last 3 system event errors
Screenshot can be captured

References

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