[cs615asa] HW5

Jan Schaumann jschauma at stevens.edu
Fri Apr 26 20:48:49 EDT 2019


I have just sent out grades for HW#5.

If you received a grade below 45/50, then you may resubmit an improved
version no later than 05/06, 16:00 EDT.  (If you scored above 45/50,
then making any improvements is not worth your nor my time.)

I am rather disappointed that quite a significant number of you appear
to not have read the assignment thoroughly and have not tested your
program on the target platform.  To quote again from

"The tool you write will be executed (and graded) on an AWS EC2 NetBSD
instance of type ami-569ed93c. You are free to develop it in some other
environment, but please make sure to test it on this instance type
before submitting it. If it does not work on these hosts, you will not
get any points."

The image noted here does notably _not_ have "/bin/bash", so any tool
written using /bin/bash as the interpreter *simply cannot possibly work*
there (and shows you did not test your program there).

To resubmit, please make whatever changes you want and submit a tar
archive as before.  The way that I will test your submission will be:

- start an instance of type ami-569ed93c
- scp your-tar-archive instance-name:
- wget https://stevens.netmeister.org/615/ec2-backup-prep
- sh ec2-backup-prep instance-name
- ssh instance-name
instance# tar xf your-tar-archive
instance# cd your-username
instance# make install
instance# /usr/local/bin/ec2-backup -h
instance# export EC2_BACKUP_VERBOSE=1
instance# /usr/local/bin/ec2-backup .
instance# /usr/local/bin/ec2-backup /

If your command passes these tests, then I will use additional
invocations; at a minimum, I will create a new volume in a different
region and then pass it to your tool via the '-v' flag.

After that, I will terminate the instance, attach the volume your tool
created to a different instance and attempt to restore the data from the
volume (e.g., "ssh new-instance-with-your-volume-attached 'dd
if=/dev/rxbd2d' | tar tvf -").

That is, being able to get the data back from the volume is critical;
recall that we don't really care about backing up data, we care about
being able to restore it!

It would be in your best interest to perform these tests yourself in
this manner.


More information about the cs615asa mailing list