AWS - add new user

IAM (identity & access management) > Users > Create New Users.
Enter user name, uncheck 'generate an access key', create
select newly-created username > 'permissions' tab > Attach policy (you can look at policies on other users if needed)
'security credentials' tab > 'assign an auto-generated password', check 'require user to create a new password at next sign-in'
download the security credentials.
(another option is to have the person stand right next to you and give themselves a temporary password)
Stick the credentials somewhere safe!
Get user to sign on and reset password.

AWS - Virtualization methods and limits

Currently AWS supports two distinct and different virtualization methods, paravirtual (PV) and hardware virtual (HV). See this page (http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/virtualization_types.html) for all the details.

For our purposes there are a few key facts

Machines cannot be moved between virtualization types
We currently use HVM. The original Hydra box was PV, but we're not longer using that style of box.

Currently we are using multiple instance types. Generally for production boxes we use either m4.large or t2.medium instance types.

The m4.large instance type was chosen due to the following requirements

Java is RAM hungry and so to make full use of tools like Fedora 8 GB of RAM was useful
m class instances have a static CPU value allowing us maintain full use of the CPU for intensive tasks

The t2.medium instance was chosen for the following reasons

Approximately 50% of the cost of m4.large instances
Able to handle usage patterns in bursts of activity rather than sustained heavy load
Reasonable resources for moderate usage

Some other tools use smaller or larger instances based on needs. Monitoring and update boxes tend to be very small.

In all instances where disk speed is an issue, select general purpose SSDs. If a disk is smaller than 100 GB this also usually easier.

In cases where disk capacity is the primary factor, select either Cold HDD or Throughput HDD volumes. They have a minimum size of 500 GB

Cold HDDs are slower but half the cost, and in cases where usage is light are preferred.
Throughput HDDS are faster and should be chosen when disk speed is a larger concern.

Fedora uses a Cold HDD for data storage due to reduced usage and the need to keep costs down.