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This article suffers from severe linkrot. It’s been a while since I wrote Parts 1,2,3,4 on my Ansible Tutorial series, but I’ve recently changed my approach somewhat when using Ansible, and certainly when I build on Parallax. I’ve started using more and more from Ansible Galaxy. For those of you who don’t know, Galaxy is a community “app store”-like thing for sharing reusable Ansible Roles. https://galaxy.ansible.com/ Let’s pretend we want to deploy a staging server for a Python/Django application, using Postgres as the backend database all on a single server running Ubuntu 14.04 Trusty. ...

This article suffers from severe linkrot. You may remember that in January, I wrote a trilogy of blogposts surrounding the use of Ansible, as a handy guide to help y’all get started. I’ve decided to revisit this now, and write another part, about Ansible Tower. In the 6-odd months since I wrote Parts 1, 2 and 3 of my Getting Started with Ansible guide, it’s had over 10,000 unique visitors. I’m quite impressed with that alone. I’ve built the ansible-based provisioning and deployment pipelines for two more companies, both based off my Parallax starting point I’ve been working on since January. That alone has been gathering Stars and Forks on Github. ...

This no longer represents good practices. Use Terraform for deploying resources to AWS instead of Ansible. By this point, you should have read Part 1: Getting Started with Ansible, and Part 2: Deploying Applications with Ansible. If you haven’t, go and do it now. You should also be familar with some of the basic concept surrounding AWS deployment, how AWS works, and so on. So, you’ll have some idea how Ansible uses playbooks to control deployment to target hosts, and some idea of the capability for deploying code from version control systems (in Part 2, we used the Ansible git: module.). ...

You should by now have worked your way through Part 1: Getting Started with Ansible. If you haven’t, go and do that now. In this article, I’ll be demonstrating a very simple application deployment workflow, deploying an insanely simple node.js application from a github repository, and configuring it to start with supervisord, and be reverse-proxied with Nginx. As with last time, we’ll be using Parallax as the starting point for this. I’ve actually gone through and put the config in there already (if you don’t feel like doing it yourself ;) ...

An introduction to Ansible Configuration Management A brief history of Configuration Management =========================================== CFEngine - Released 1993. Written in C Puppet - Released 2005 - Written in Ruby. Domain Specific Language (DSL. SSL Nightmare. Chef - Released 2009 - Written in Ruby, also a DSL, more like pure Ruby Juju - Released 2010, Python, Very ubuntu. Salt - Released 2011, Python, Never got it working right Ansible - Released 2012, Python. Awesome. Why Ansible? It’s agentless. Unlike Puppet, Chef, Salt, etc.. Ansible operates only over SSH (or optionally ZeroMQ), so there’s none of that crap PKI that you have to deal with using Puppet. ...

What does VPN stand for? Virtual Private Network. Moving on… What is a VPN? A VPN is a mechanism to extend a private network (like your LAN [Local Area Network]) across a public network (like the Internet). The upshot of this is, that you can connect two separate computers, each on their own LAN, across a VPN so that they appear to be on the same network; which, in a sense, they are. ...

We live in a dangerous world. It should come as no surprise to anyone who is a Citizen of the Internet, that the risks of interacting with others on the ’net is a somewhat dangerous business. Riskier still, is operating a server, or entire network with direct connection to the internet. The number of denial of service and code execution exploits has risen dramatically in the last decade, unsurprisingly. The number of black-hat hacking attempts (to use “hacking” from the vernacular of the media - rather than it’s true, nobler meaning) has also risen. ...

I’ve been tinkering with Virtualisation quite a bit recently. For a new project, without an allocated budget, I was asked to provide some simple Virtualisation capability, to hold them over until they get budget approval, and can buy their own hardware. I managed to rescue a Dell R510 server from the scrap heap, only to discover that it contains a Dell S300 “FakeRAID” card, that’s not supported by Linux (so KVM, Xen et al are out). It’s also not supported by VMWare ESXi, so that’s out. The only OS that is supported is Windows, and Windows Server. ...

NEVER. That’s got that off my chest. eval() is possibly the most dangerous thing ever. It’s basically a way to execute arbitrary code from a string or variable. Here’s a few reasons why it’s dangerous. It leaves you open to injection attacks. In Javascript, eval() forces the engine to drop into Interpreter mode, which slows down your application, and it will remain slow, as there’s no opportunity for optimisation-level caching to take place. ...

Symptoms: Some clients are unable to connect to the internet. Some clients report a different IP address, subnet mask and default gateway, compared to others. Caveats: Without a managed switch fabric, this is considerably more difficult. Diagnosis: Allow a device to get an IP address from the rogue server. You might need to disable the main DHCP server to allow this to happen, as DHCP is a broadcast protocol, so it’s really a case of the early bird getting the worm. Kyle Gordon pointed out that this initially assumes that the DHCP server is the same as the default gateway. He suggests: Usually /var/lib/dhcpcd/.info or /var/lib/NetworkManager/ will contain the dhcp-server-identifier info on Linux, and something in the Windows Event Logs will show similar :-) ...