Transparent Huge Pages on Hadoop makes me sad.

Today I (re)learned that I should pay attention to the details of Linux kernel bugs associated with my favorite distribution. Especially if I’m working on CentOS 6/Red Hat Enterprise Linux (RHEL) 6 nodes running Transparent Huge Pages on Hadoop workloads. I was investigating some performance issues on our largest Hadoop cluster related to Datanode I/O […]

Resizing a multipathed SAN LUN under RHEL5

So today I found myself staring at the Red Hat LVM documentation wherein I began to silently cuss.  You see, I needed to double the LUN size for MySQL’s usage on one of my servers.  These servers are our first that are directly attached into the SAN and running Linux, so we’re working a bit […]

Ubuntu Linux adds private cloud backing | Open Source – InfoWorld

Ubuntu Linux adds private cloud backing Canonical’s upcoming server upgrade supports the Eucalyptus project’s open source system for cloud implementation using hardware and software already in place Canonical is touting private cloud capabilities in an upgrade to its Ubuntu Linux OS being announced on Tuesday. Available for free download on October 29, Ubuntu 9.10 Server […]

Tips: See the contents of an RPM post-install script

Today I had the need to look at’s post-install scripts for MySQL Advanced. Unfortunately, I was lazy not having quick and easy access to the specfile, I used my blackbelt in Google-fu to figure out that it was simpler than I thought. In my case, I had already installed the RPM. All I needed […]

Woot! Unix group enumeration from AD groups.

Well, that was easy enough. Just needed to understand a bit more of the AD OU structure here. (Sanitized a bit for now). -bash-3.2$ touch foo bar baz quux -bash-3.2$ ls -l total 0 -rw-r–r– 1 hcoyote UNIXTEST-test 0 Jun 3 16:59 bar -rw-r–r– 1 hcoyote UNIXTEST-test 0 Jun 3 16:59 baz -rw-r–r– 1 hcoyote […]

Ha ha! SSL success for AD/LDAP.

Ha ha! Further success on the Linux -> Active Directory integration front. I got SSL working for the underlying ldap bind user. What’s this mean? Protection of the directory information over the wire as it travels from the domain controller to the client host where it will be used. So what’s the necessary setup bits?  […]

Authenticating to Austin AD from Linux

Woot!  With the help of barthag, I got one of our linux boxes configured to provide passwd file map backend via AD/LDAP and authentication via AD/Kerberos.  Most of the problems stem from permissions issues on the AD side and making sure things are open “enough” to let us through to query for information. On the […]

Useful LDAP/Kerberos integration resources

I was recently in a meeting discussing the integration of Unix account management (passwd and group) with Active Directory via LDAP and Kerberos.  Having done some of this at a previous job, I’d already done some research into getting it working.  I found some useful resources back then on getting this all working right.  I […]