Add info about possibility of running Android emulators on EC2 instances (#656)

README.md

@@ -808,7 +808,7 @@ EC2
 ### EC2 Basics
 
 -	📒 [Homepage](https://aws.amazon.com/ec2/) ∙ [Documentation](https://aws.amazon.com/documentation/ec2/) ∙ [FAQ](https://aws.amazon.com/ec2/faqs/) ∙ [Pricing](https://aws.amazon.com/ec2/pricing/) (see also [ec2instances.info](http://www.ec2instances.info/)\)
--	**EC2** (Elastic Compute Cloud) is AWS’ offering of the most fundamental piece of cloud computing: A [virtual private server](https://en.wikipedia.org/wiki/Virtual_private_server). These “instances” can run [most Linux, BSD, and Windows operating systems](https://aws.amazon.com/ec2/faqs/#What_operating_system_environments_are_supported). Internally, they've used a heavily modified [Xen](https://en.wikipedia.org/wiki/Xen) virtualization. That said, new instance classes are being introduced with a KVM derived hypervisor instead, called [Nitro](http://www.brendangregg.com/blog/2017-11-29/aws-ec2-virtualization-2017.html). So far, this is limited to the C5 and M5 instance types. Lastly, there's a "bare metal hypervisor" available for [i3.metal instances](https://aws.amazon.com/blogs/aws/new-amazon-ec2-bare-metal-instances-with-direct-access-to-hardware/) in a limited preview.
+-	**EC2** (Elastic Compute Cloud) is AWS’ offering of the most fundamental piece of cloud computing: A [virtual private server](https://en.wikipedia.org/wiki/Virtual_private_server). These “instances” can run [most Linux, BSD, and Windows operating systems](https://aws.amazon.com/ec2/faqs/#What_operating_system_environments_are_supported). Internally, they've used a heavily modified [Xen](https://en.wikipedia.org/wiki/Xen) virtualization. That said, new instance classes are being introduced with a KVM derived hypervisor instead, called [Nitro](http://www.brendangregg.com/blog/2017-11-29/aws-ec2-virtualization-2017.html). So far, this is limited to the C5 and M5 instance types. Lastly, there's a "bare metal hypervisor" available for [i3.metal instances](https://aws.amazon.com/about-aws/whats-new/2018/05/announcing-general-availability-of-amazon-ec2-bare-metal-instances/)   
 -	The term “EC2” is sometimes used to refer to the servers themselves, but technically refers more broadly to a whole collection of supporting services, too, like load balancing (CLBs/ALBs/NLBs), IP addresses (EIPs), bootable images (AMIs), security groups, and network drives (EBS) (which we discuss individually in this guide).
 -	💸**[EC2 pricing](https://aws.amazon.com/ec2/pricing/)** and **[cost management](#ec2-cost-management)** is a complicated topic. It can range from free (on the [AWS free tier](https://aws.amazon.com/free/)) to a lot, depending on your usage. Pricing is by instance type, by second or hour, and changes depending on AWS region and whether you are purchasing your instances [On-Demand](https://aws.amazon.com/ec2/pricing/on-demand/), on the [Spot market](https://aws.amazon.com/ec2/spot/) or pre-purchasing ([Reserved Instances](https://aws.amazon.com/ec2/pricing/reserved-instances/)).
 - **Network Performance:** For some instance types, AWS uses general terms like Low, Medium, and High to refer to network performance. Users have done [benchmarking](http://stackoverflow.com/questions/18507405/ec2-instance-typess-exact-network-performance) to provide expectations for what these terms can mean.
@@ -869,6 +869,7 @@ EC2
 -	Very new accounts may not be able to launch some instance types, such as GPU instances, because of an initially imposed “soft limit” of zero. This limit can be raised by making a support request. See [AWS Service Limits](http://docs.aws.amazon.com/general/latest/gr/aws_service_limits.html) for the method to make the support request. Note that this limit of zero is [not currently documented](http://docs.aws.amazon.com/general/latest/gr/aws_service_limits.html#limits_ec2).
 - Since multiple AWS instances all run on the same physical hardware, early cloud adopters encountered what became known as the [Noisy Neighbor problem](https://searchcloudcomputing.techtarget.com/definition/noisy-neighbor-cloud-computing-performance). This feeling of not getting what you are paying for led to [user frustration](https://twitter.com/technicallyjosh/status/668963405831651328), however "steal" may not be the best word to describe what's actually happening based on a [detailed explanation of how the kernel determine steal time](https://support.cloud.engineyard.com/hc/en-us/community/posts/203751578-Explanation-of-Steal-Time). Avoiding having CPU steal affect your application in the cloud may be best handled by [properly designing your cloud architecture](https://www.infoworld.com/article/3073503/cloud-computing/debunking-the-clouds-noisy-neighbor-myth.html).
 - AWS [introduced Dedicated Tenancy](https://aws.amazon.com/blogs/aws/amazon-ec2-dedicated-instances/) in 2011. This allows customers to have all resources from a single server. Some saw this as a way to solve the [noisy neighbor problem](https://www.infoworld.com/article/3008225/cloud-computing/amazon-dedicated-hosts-bye-bye-to-noisy-cloud-neighbors.html) since only that customer uses the CPU. This approach comes with a significant risk if that physical system needed any type of maintenance. If a customer had 20 instances running using shared tenancy and one underlying server needed maintenance, only the instance on that server would go offline. If that customer had 20 instances running using dedicated tenancy, when the underlying server needs maintenance, all 20 instances would go offline. 
+-	🔸Only **i3.metal** type instances providing an ability to run Android x86 emulators on AWS at the moment.