Josh Wieder

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...

A few of my Red Hat servers run cron jobs to check for updates. starting yesterday (Thursday October 1st, 2015) at around 3PM I encountered 503 unavailable errors when attempting to contact a Fedora Project URL that hosts the metalink for the  rhui-REGION-rhel-server-releases repository - a core RHEL repository for EC2. Could not get metalink  https://mirrors.fedoraproject.org/metalink?repo=epel-7&arch=x86_64  error was 14: HTTPS Error 503 - Service Unavailable 3 hours later or so, the URL began responding again, but the problems remained. `yum` now reports corrupted update announcements from the repo: Update notice RHSA-2014:0679 (from rhui-REGION-rhel-server-releases) is broken, or a bad duplicate, skipping. You should report this problem to the owner of the rhui-REGION-rhel-server-releases repository. Update notice RHSA-2014:1327 (from rhui-REGION-rhel-server-releases) is broken, or a bad duplicate, skipping. Update notice RHEA-2015:0372 (from rhui-REG...

About a month and a half ago I grew so frustrated by the boneheaded way that Amazon EC2 handles IP aliasing that I wrote a pretty lengthy post about the problems entailed and included a small program that would fix those problems . Amazon provides some pretty productive documentation for some types of users. There is help available for you if you are any one of the following:      - You are willing to pay for a new ENI to support a second IP address      - You are multihoming / load balancing      - You want to use "Amazon Linux" and install their ec2-net-utils But, if you want to just add a second IP address to a pre-existing Linux server, you are pretty much screwed. Well, you were screwed. Now you can install my program - aliaser - as a service and it will route additional IP addresses for you without the need for an extra ENI. I've uploaded aliaser to Github   - it includes a shell script and a .service file, as well...

UPDATE March 1st, 2017 : I'm glad to see that people are finding this helpful, and thanks to everyone that has contacted me here or via email. Just to be clear, though, the script on GitHub works much better than what I describe here in this post. The idea for this post was to describe the basics of how to get IP aliasing working in EC2 w/out using Amazon's weirdo linux distro, and I wrote it about a while before I posted the script to GitHub . If you want functional code with step-by-step instructions, goto the aliaser GitHub repo . I just don't have the time to rewrite the post each time I (or someone else) has an update for the script. Also, if you have feature requests or feedback, it will be easier for me to get back to you on GitHub than here ... especially if you have something specific you want added or that doesn't work. Also, just FYI, I added a systemd .service file to the script in the aliaser GitHub repo a year ago. IIRC its LFB compatible so should wo...

When installing the vulnerability scanner application Nikto/Nikto2 using yum with RedHat Enterprise Linux 7 or CentOS 7 or even Scientific Linux 7, the odds are good that you will encounter some irritating problems. Namely, the installation will fail while requiring a dependency that appears to not exist for the version of linux you are using. Fun! So you probably think you are safe if you install OpenVAS , a prepackaged suite of security utilities that includes Nikto as a plugin. But you would be wrong! Installing OpenVAS from an RPM will succeed, and everything will look fine, until you try to use Nikto within OpenVAS, which will result in a fatal error. Nikto is included in the Extra Packages for Enterprise Linux/EPEL yum repository all recent versions of RedHat linux, which is part of the Fedora Project. While it contains third party applications, it is not a third party repository like RPMFusion or Atomicorp . I have only very rarely had problems with the EPEL yum repo, and t...