accessing files under a mount point (getting at the files that have been obscured by another filesystem mounted on top of them)

This has come up 3 times in the last few days so I thought I'd share it. The situation is that there are files at /var/spool/mqueue that are part of the /var filesystem. But there is also another filesystem mounted at /var/spool/mqueue with it's own files. You want to access the files under the mount but you can't. So, there are two ways around this (in this instance).

Option 1

Updated slides for my talks at LOPSA-EAST

Overview of KVM
Intro to puppet

Thanks everyone who came to the talks, great conference this year. Thanks to puppetlabs for all the support. Getting better every year, looking forward to next year! (just hope it stays smaller than LISA)

using augeas to add a user to the system

The scenario is that users are controlled by sssd and you want to add a user locally for those times when your connection to your password backend goes down. Useradd won't let you do it though, cause the user already exists. I figured augeas would be the perfect way to do that but I kept hitting a problem, augeas would fail.

streaming dlna from fedora to a Samsung TV (mediatomb)

I was trying to get my Samsung TV to play files from my Beefy miracle box and although it was able to connect, it would not show any files. It took a bit of hunting around but I found the following patch needed to be applied to get the files to display.
 

linux-kvm talk

A talk I gave at Lopsa NJ on linux-kvm, slides in a google doc here

John recorded the talk so maybe it'll be posted on lopsa's website soon...

skype 4.1 on RHEL6 (Springdale Linux/PUIAS)

The latest version of skype doesn't appear to work well on RHEL6, I found the following forum http://community.skype.com/t5/Linux/Skype-for-Redhat-Enterprise-6/td-p/1... and followed the two things mentioned there to make it work.

  • Download the ubuntu 10 version and extract the contents with dpkg

puppet nfs export with augeas

I wanted to be able to define nfs shares with puppet and have puppet take care of the exports line and exportfs. I found this page, but I didn't like that there was perl code thrown in the midst. I rewrote it to use an inline template instead.

using nested acl's with exim

I wanted to configure rate limiting on our exim server and needed to setup an ACL that I could include in multiple spots in the configuration. The keyword acl = acl_name is supported (referred to as nested ACL's) but the logic took a little bit of thought...

I want to ratelimit users, the acl for that is here:

  warn  authenticated   = *

using a large floppy image with memdisk

I ran into a snag when trying to update the bios on my PE R210ii, the Bios update is 8MB, too large to fit on a floppy image, so I needed to make a floppy image large enough for the file. I tried increasing the size of the Dell floppy image and that didn't work, so I had to start from scratch with a boot floppy made from windows. Funny enough the first link that came back in my google search was that of my coworker.

creating a password hash for /etc/shadow (sha512,sha256,md5)

I've run into this enough times that I thought I'd write a little script to do the work for me.
It's just a simple one line call to python, but I wrapped it with some argument parsing.

It's a python script that takes a password and returns the salted sha512 hash by default. sha256 and md5 can be specified with switches.