Category Archives : Sys admin


grub rescue

When in grub rescue, you only got insmod, ls, set, unset (I think). Thus, you must insmod the required modules in order to be able to do anything substantial. do: set root=<whatever> set prefix=<whatever>/boot/grub where <whatever> is like (md0) or (hd2,1). the /boot/grub is by default where modules are, so that insmod will work. If […]


svn tunneling

subversion uses ssh. If ssh blocked from A to C, but A-> B and B->C is not blocked, setup tunneing:   1. on A: /etc/subversion/config in the [tunnel] section, add: ssh = $SVN_SSH ssh -o ControlMaster=no <machine B’s hostname> ssh -o ControlMaster=no   2. on B: /etc/ssh/ssh_config HostbasedAuthentication yes EnableSSHKeysign yes   3. on C […]


A Musing on WordPress and Website Hacking

Introduction As an owner of a software and IT company, I love to solve technical problems. That’s why when recently sites I own and run, as well as my customers’ sites, were seemingly infected with malware (through no fault of mine or the company’s, more on this later), and having swiftly removed the said malware, […]


Setting up Hadoop Cluster with ubuntu

Installation Install hadoop: https://ccp.cloudera.com/display/CDHDOC/CDH3+Installation (optional) Links to installing hive/pig/hbase are on the bottom of the link in step 2. Configuration Hive:  by default it does not allow multiple users, because by default it uses a local derby metastore. So, if you wish to have multiple users connect to it, install mysql, and configure /etc/hive/conf/hive-site.xml.  See […]


Linux rescue from grub busybox

When SOL and linux won’t boot (i.e. like /etc/fstab is misconfigured, which prevents you from booting and correctly configuring /etc/fstab…chicken and the egg type of situation…), you could in theory boot with a live cd or something along those lines. Otherwise, you can, from grub (i.e. grub menu -> find the entry you’re booting with, […]


Ubuntu Black Magic

Shrinking Root with Software Array, then Replacing Root with another Root Image 0. Start console.  This is a hardware thing, whereby you can monitor the system console even during a reboot.  For example: ssh [email protected] start /SP/console escape + ( gets out of the console.  then, you can do a “reset/SYS” to reboot   Take […]