Integrate EC2 doc links into the text.
When in doubt https.
More https.
Emphasize the choices the user has to make.
Minor sentence structure edit for better flow.
minor grammar edit plus a typo fix
minor grammar edit
Tie these two sentences together more closely since the latter affects the interpretation of the former.
It is important that nodes can SSH to each other as well!  Restructure this advice to make it clear what the SSH requirements are and let them make up their mind about any restrictions to put in place.
Don't assume they'll generate a new key.
Direct them to find the address information.
Do not put a real, public IP address into the documentation.
Start getting rid of the "we" voice for consistency.
Continue getting rid of the "we" voice.
Avoid prompting for input during the upgrade.
Simpler way to get a good authorized_keys file.