Trace your python programs

Bash programming has a very helpful command of:

bash -x myscript.sh

This will show you what bash is doing while running through myscript.sh. Python has the same functionality, through this command:

python -m trace --trace myscript.py 

Very useful in debugging python programs.  Additional info:

http://docs.python.org/library/trace.html

Create ssh public key from private key

If you have a private key and want to create the public key from that (to put in ~/.ssh/authorized_keys, for example), do the following:

ssh-keygen -f <my_private_key> -y > <my_public_key>

For example:

ssh-keygen -f ~/.ssh/id_rsa -y > ~/.ssh/id_rsa.pub


If you are using this to ssh with keys, add my_public_key (eg. ~/.ssh/id_rsa.pub) to ~/.ssh/authorized_keys on the remote server.

Then ssh with the private key to the remote server to test.

EC2 Bundling an AMI -- Server.InternalError: An internal error has occurred

Once you try to re-bundle an OS image that has been previously bundled, it will complain about /etc/ec2/amitools/cert-ec2.pem not being present.  I figured that was my certificate, but it is  EC2's X.509 public key certificate, not mine (docs are somewhat confusing about that).  Since they were stripped out of the AMI last time it was bundled, I reinstalled the tools to restore these certs and no errors any more.

AWS API tools:

http://aws.amazon.com/developertools/368

Hope this helps.

Original EC2 forum posts:

https://forums.aws.amazon.com/thread.jspa?messageID=345021

https://forums.aws.amazon.com/message.jspa?messageID=344101

Ubuntu and EC2

Great blog on the nitty gritty of working with EC2:

http://alestic.com/

Install Cisco AnyConnect on Ubuntu/Debian/Mint 64 bit

Looks like there are no 64 bit Cisco AnyConect VPN Clients.  Here is a workaround to get them working on a Debian-based 64 bit OS:

http://www.virtualcorner.nl/?page_id=220

Linux Mint on Gigabyte GA-Z68X-UD3H-B3

I tried to install Linux Mint on a desktop with Gigabyte GA-Z68X-UD3H-B3 motherboard with its Intel raid array configured with two of three hard drives.  I wanted to install Linux Mint 12 x64 on the third drive.  When trying to boot, I got the error message:

udev timeout killing /sbin/modprobe -bv pci:

I had to add the grub option of nomodeset as a kernel paramater.  It then was able to install from there.  Here are more details:

http://forums.linuxmint.com/viewtopic.php?f=46&t=95351&p=547012#p545731

DenyHosts setup on Red Hat/Centos/Amazon AMIs

This is a really useful tutorial for setting up DenyHosts to protect against brute force ssh attacks.

http://www.cyberciti.biz/faq/rhel-linux-block-ssh-dictionary-brute-force-attacks/

DenyHosts homepage:

http://denyhosts.sourceforge.net/

pv

This was so good I had to repost it here.  It is about a useful utility called pv which shows a progress report of running processes:

http://www.dp.cx/blog/pv--one-of-the-most-useful-applications-around.html