amazon web services - AWS EC2 Instance - Is it a single virtual image or single physical machine? - Stack Overflow
Which operating systems can you run on an Amazon EC2 instance?
A. Only Linux.
B. Only Windows.
C. Only macOS.
D. Both Linux and Windows.
What does an Amazon Machine Image (AMI) represent in EC2?
A. A snapshot of an EC2 instance.
B. A script to deploy applications on EC2.
C. A security group for an EC2 instance.
D. A billing configuration for EC2 usage.
Can someone explain like im 5 for EC2?
What software does Amazon use for creating EC2 instances on the fly?
An EC2 instance is a VM that gets some percentage of the underlying physical host's RAM, CPU, disk, and network i/o. That percentage could theoretically be 100% for certain instance types, including bare-metal instances, but is typically some fraction depending on which instance type you choose.
ELB is a service, not a single EC2 instance. It will scale on your behalf. It routes by round robin for TCP, and routes on fewest outstanding requests for HTTP and HTTPS.
Auto Scaling is "scale out" (it adds new EC2 instances), not "scale up" (resizing an existing EC2 instance). It launches a new instance from a template called an AMI.
- It is a virtual server, a VM, as stated in the documentation.
- It's a little more complicated that that, based on the way AWS might scale the load balancer, or create a version in each availability zone, etc. It also provides more features such as auto-scaling integration, health checks, SSL termination. I suggest you read the documentation.
- It uses a machine image that you specify when you create the auto-scaling group (when you create the Launch Configuration used by the Auto-scaling group to be more precise). A common practice is to configure a machine image that will download any updates and launch the latest version of your application on startup.
You might also be interested in Elastic Beanstalk which is a PaaS that manages much of the AWS infrastructure for you. There are also third-party PaaS offerings such as OpenShift and Heroku that also manage AWS resources for you.