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Showing posts with the label CentOS

Setting a hostname for your Amazon AWS EC2 server running RHEL or CentOS 7

So it turns out that setting your AWS EC2 server's hostname to be persistent across reboots is a surprising pain in the ass, at least with my usual OS of choice - RedHat/CentOS Linux. If you're like me, setting a hostname is the sort of trivial non-task that at this point you really feel like you dont need to RTFM  to figure out. You know about `hostnamectl set-hostname`. You've tried `nmcli general hostname`. You've manually set /etc/hostname. None of its persists past a reboot. Which can make life very difficult for those planning to use EC2 for email or dozens of other tasks. Here's how to do it the right way, the first time. I'll also describe some circumstances that setting your own hostname will break things, and why its such a hassle to get this done in AWS in the first place. Amazon relies on cloud-init to manage a variety of initialization tasks for its cloud servers; cloud-init was originally built to support Ubuntu images , but it is now used fo

How To Find Files Over a Certain Size Using Redhat/CentOS/Fedora Linux

Here is a quick tip for all of those Redhat/CentOS/Fedora users out there. Do you need to find all files over a certain size, either in a specific directory, your current directory, or in your entire computer/server? No problem, just execute the following: find / -type f -size +500000k -exec ls -lh {} \; | awk '{ print $9 ": " $5 }' In the example above, I am looking for all files over 500MB in size (500000k, where k = kilobytes). The place where I have typed "/" in the above command indicates the path to search in. By selecting "/" I am searching in the entire filesystem; I could easily indicate a specific directory by changing my command as follows: find /path/to/my/directory -type f -size +500000k -exec ls -lh {} \; | awk '{ print $9 ": " $5 }' Alternatively, I could search in my current directory by replacing "/" with "." like so: find . -type f -size +500000k -exec ls -lh {} \; | awk '{ pri

Patching Your Redhat Server for the Shellshock Vulnerability

Introduction Alright guys, this is a biggie. Shellshock allows remote code execution and file creation for any server relying on bash v3.4 through v1.1. If you are using Redhat or CentOS and the default shell, your server is vulnerable. The patching history was sketchy, as well. If you patched immediately when the bug came out using  CVE-2014-6271 , you are still likely vulnerable (as of right now, 9/26/2013 12:50PM EST). Run the following to apply the patch: #yum update bash You need CVE-2014-7169  if you are using Red Hat Enterprise Linux 5, 6, and 7. Note that 2014-7169 DOES NOT address the following operating systems, which as of right now are still not fully patched: Shift_JIS, Red Hat Enterprise Linux 4 Extended Life Cycle Support, Red Hat Enterprise Linux 5.6 Long Life, Red Hat Enterprise Linux 5.9 Extended Update Support, Red Hat Enterprise Linux 6.2 Advanced Update Support, and Red Hat Enterprise Linux 6.4 Extended Update Support If you applied CVE-2014-6271 and nee

File Defragmentation Tools for Windows 2003/2008, Redhat/CentOS and Ubuntu

For managing fragmentation of NTFS (Windows Server 2003/2008, XP, Vista, and Windows 7) : For general disk defragmentation, the following utilities offer a substantial improvement in overall performance and efficacy over native operating system tools: Auslogics Disk Defrag  or Raxco PerfectDisk For use on disks unsupported by the above tools, frequently executed and/or locked files or even a straightforward command line utility that can easily be used as part of a shell script: Contig from the Sysinternals Suite Contig has been of particular value when managing backup servers - servers storing huge files with substantial writes on a regular basis. Being able to specify the backup files allows for properly scheduling defragmentation by backup job, and in the process eliminating the need for downtime on these systems as part of this manner of disk maintenance. Can also be used for per-file fragmentation analysis and reporting. For managing fragmentation of ext4 file systems (new

Thank You!

When I started this site 6 months ago, I expected it to be a sort of notebook for quick fixes of server and router problems. I had hoped to use this as a place where the solutions to IT brain ticklers could be posted in case I forgot them and needed them later. Because almost all of my friends work in the same industry I do, it quickly became a place where I could refer people I knew who were in a bind and in return I post fixes they come across. Other than letting a few close friends and family know about the site and bugging them for feedback and ideas every now and again, or sending out the occasional twitter/linkedin post,I haven't really told anyone about it. I certainly haven't marketed the site or engaged in any sort of 'search engine optimization'. That's why I don't quite know what to make of the sheer number of visitors to the site. At this point, the count is in the tens of thousands, with traffic doubling every single month. Here is what the traf