<h2>Innovative Multi-node Control<aclass="headerlink"href="#innovative-multi-node-control"title="Permalink to this headline">¶</a></h2>
<h1>Innovative Multi-node Control<aclass="headerlink"href="#innovative-multi-node-control"title="Permalink to this headline">¶</a></h1>
<p>Where Ansible excels though, is expressing complex multi-node
deployment processes, executing ordered sequences on
different sets of nodes through <aclass="reference internal"href="playbooks.html"><em>Playbooks</em></a>. Playbooks contain one or
@ -184,7 +181,7 @@ version of software if required.</p>
<p>Multi-machine software deployment is poorly solved by most systems management tools – often due to architectural nature of being pull oriented and having complex ordering systems, they cover configuration but fail at deployment when updating tiers of machines in well defined steps. This results in using two (or more) logically distinct tools and having complex overlap between them.</p>
<h2>Deployment and Configuration, Unified<aclass="headerlink"href="#deployment-and-configuration-unified"title="Permalink to this headline">¶</a></h2>
<h1>Deployment and Configuration, Unified<aclass="headerlink"href="#deployment-and-configuration-unified"title="Permalink to this headline">¶</a></h1>
<p>Other deployment (compared to config) oriented frameworks similarly cover deployment well but lack a strongly defined resource model and devolve into glorified remote scripts. Ansible playbooks – having been designed with this problem in mind – are good at both deployment & idempotent configuration, meaning you don’t have to spread your infrastructure management out between different tools (Puppet+Capistrano, Chef+Fabric, etc), and performing ordered steps between different classes of machines is no problem, yet our modules affect system state only when required – while avoiding the problem of fragile scripting that assumes certain starting
or ending states.</p>
<p>Ansible is also unique in other ways. Extending ansible does not require programming in any particular language – you can write <aclass="reference internal"href="modules.html"><em>Ansible Modules</em></a> as idempotent scripts or programs that return simple JSON. Ansible is also pragmatic, so when you need to, it’s also trivially easy to just execute useful shell commands.</p>
@ -196,21 +193,19 @@ to use (not being code) and also allows intermixing of idempotent configuration
of control. Further, it was designed for deploying multi-node applications from the beginning.</p>
</div>
<divclass="section"id="simple-secure-by-default">
<h2>Simple & Secure By Default<aclass="headerlink"href="#simple-secure-by-default"title="Permalink to this headline">¶</a></h2>
<h1>Simple & Secure By Default<aclass="headerlink"href="#simple-secure-by-default"title="Permalink to this headline">¶</a></h1>
<p>Compared with most configuration managememnt tools, Ansible is also much more secure. While most configuration management tools use a daemon, running as root with full access to the system, with its own in-house developed PKI infrastructure, Ansible just uses SSH (and supports sudo as neccesssary). There is no additional attack surface and OpenSSH is one of the most peer reviewed security components out there.
If a central server containing your playbooks are comprimised, your nodes are not – which is NOT the case
of these other tools, which can, more or less, turn into a botnet. Our security approach is to avoid writing custom
crypto code altogether, and rely on the most secure part of the Linux/Unix subsystem that your machines are already using. There is no PKI subsystem to maintain, which can be a frequent source of problems, particularly when reinstalling or migrating
hosts.</p>
<p>Systems management doesn’t have to be complicated. Ansible’s docs will remain short & simple, and the source will be blindingly obvious. We’ve learned well from “Infrastructure is Code”. Infrastructure should be easy and powerful to command, but it should not look like code, lest it acquire the disadvantages of a software project – bugs, complexity, and overhead. Infrastructure configurations should be simple, easy to develop, and easy to audit.</p>
</div>
</div>
<divclass="section"id="architecture">
<h1>Architecture<aclass="headerlink"href="#architecture"title="Permalink to this headline">¶</a></h1>
<h2>Architecture<aclass="headerlink"href="#architecture"title="Permalink to this headline">¶</a></h2>
<h1>About the Author<aclass="headerlink"href="#about-the-author"title="Permalink to this headline">¶</a></h1>
<h2>About the Author<aclass="headerlink"href="#about-the-author"title="Permalink to this headline">¶</a></h2>
<p>Ansible was originally developed by <aclass="reference external"href="http://michaeldehaan.net">Michael DeHaan</a> (<aclass="reference external"href="http://twitter.com/#!/laserllama">@laserllama</a>), a Raleigh, NC
based software developer and architect. He created the popular
DevOps program <aclass="reference external"href="http://cobbler.github.com/">Cobbler</a>.
@ -385,6 +380,7 @@ orchestrate systems in lots of diverse places. He’s worked on systems
software for IBM, Motorola, Red Hat’s Emerging Technologies Group,
Puppet Labs, and rPath. Reach Michael by email <aclass="reference external"href="mailto:michael.dehaan%40gmail.com">here</a>.</p>
<spanid="patterns"></span><h1>The Inventory File, Patterns, and Groups<aclass="headerlink"href="#the-inventory-file-patterns-and-groups"title="Permalink to this headline">¶</a></h1>
Michael DeHaan
13 years ago