OverAPI.com – Collecting All Cheat Sheets
In a recent project I crashed into a wall. At least for a couple of days that is. The requirement was to integrate the Request Tracker (aka RT) installation on CentOS 7 server with Nginx to a client’s company single sign-on solution. Which wasn’t LDAP. Or Active Directory. Or anything standard at all – a complete homegrown system.
Install Elastix from USB Step by Step – came in quite handy for the box that has no DVD drive.
NISE Nexcom Series – a good selection of embedded servers and mini-PCs for home and small office needs. These things don’t require a lot of power or a dedicated cooling system, and have native support for Linux.
Inside NGINX: How We Designed for Performance & Scale
The #! magic, details about the shebang/hash-bang mechanism on various Unix flavours
ClearOS – IT infrastructure Linux distribution.
I spent a large chunk of yesterday experimenting with Vagrant on my Fedora 21 laptop. I’ve used it before of course, but a friend asked for help with something I was planning to play with for a long time, so it unexpectedly lead me into a journey.
Let’s start simple. If you want the least possible amount of hassle with running Vagrant on Fedora, you should use it with Oracle VirtualBox provider (sometimes also called hypervisor). It works great! The only troubles with this approach is that VirtualBox relies on a kernel module (kmod-VirtualBox RPM), which has to match your current running kernel version to a digit. This kernel module is NOT part of the official Fedora repositories, and, instead, can be found in the RPM Fusion yum repository (rpmfusion-free-updates). This means that sometimes, when Fedora releases a kernel update, it might take a few days for the RPM Fusion repository to catch up with the kmod-VirtualBox updates. And this, of course, might result in your Vagrant setup being broken.
The easiest way to protect against that is to disable automatic kernel, kernel module and VirtualBox updates. To do so, add the following line to the [main] section of your /etc/yum.conf file, right after your VirtualBox/vagrant setup started to work:
exclude=kernel* kmod-* VirtualBox*
Now, if you forgot to do that a few times got pissed off with this situation (or don’t like Oracle for some reason), you might consider alternatives. Which are a few. Vagrant supports a variety of hypervisors. One of the common alternatives is to use libvirt, which is shipped with Fedora distribution.
Installing libvirt is simple (thanks to this blog post). Here’s pretty much all you have to do:
yum install libvirt libvirt-daemon libvirt-daemon-qemu virt-manager service libvirtd restart
The problem that you might realize now is that libvirt is not the most popular provider for boxes in the Vagrant world. Most people seem to prefer VirtualBox. But if your choices are satisfied, I’m glad for you. If they are not, however, there is a work around that you might go for – vagrant mutate plugin. This plugin converts vagrant boxes from one hypervisor to another.
In order to install this plugin on Fedora 21 you’ll need a few development tools first (this StackOverflow thread definitely helped with the weird g++ error):
yum install ruby-devel gcc-c++ make
Once you have those, install the vagrant plugin with your regular user (the one who will run vagrant VMs):
vagrant plugin install vagrant-mutate
Now you can mutate Vagrant boxes. Unfortunately, you might find that mutate plugin doesn’t like boxes with slash in their names (like chef/centos-6.5). The suggested workaround is to either use box names without slashes, or to provide mutate plugin with the box URLs, rather than names. The official boxes directory doesn’t give you URLs though, so you might be stack with random GitHub repositories or with an alternative directory, like Vagrantbox.es.
My adventures with this aren’t over yet. Feel free to send suggestions my way. From my side, here are a couple of other useful links on this subject:
- It looks like the upcoming Fedora 22 will handle things better.
- If you are using Vagrant boxes on Windows, you are probably familiar with file permission issues across synced folders.
- If you want to have several VMs with Vagrant, here are some handy configuration snippets for those who aren’t well versed in Ruby.
One last bit of advise from me is that until you are absolutely sure that your Vagrant setup works perfectly, stick to 32-bit box images. There’s nothing like ripping your hair out for three hours only to learn that your host hardware is 32-bit while you are trying to boot into a 64-bit operating system.
I nearly had a heart attack … it took me a couple of seconds to realize that this was a prank…
Well played, well played …
P.S.: For those of you who don’t know who Richard Stallman is – shame on you. :)
P.P.S.: Easy for you to spot the “bot” part here, but I saw on this on the mobile app, which was more insisting on the name rather than the handle.
I came across “Do Not Use Amazon Linux” opinion on Ex Ratione. I have to say that I mostly agree with it. When I initially started using Amazon Web Services, I assumed (due to time constraints mostly) that Amazon Linux was a close derivative of CentOs and I opted for that. For the majority of things that affect applications in my environment that holds true, however it’s not all as simple as it sounds.
There are in fact differences that have to be taken into account. Some of the configuration issues can be abstracted with the tools like Puppet (which I do use). But not all of it. I’ve been bitten by package names and version differences (hello PHP 5.3, 5.4, and 5.5; and MySQL and MariaDB) between Amazon AMI and CentOS distribution. It’s an absolute worst when trying to push an application from our testing and development environments into the client’s production environment. Especially when tight deadlines are involved.
One of the best reasons for CentOS is that developers can easily have their local environments (Vagrant anyone?) setup in an exactly the same way as test and production servers.