132 lines
5.5 KiB
Markdown
132 lines
5.5 KiB
Markdown
[[!meta title="Migrating away from puppet to cdist"]]
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For those not being subscribed to the puppet-users mailing list,
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here's my
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["goodbye and thanks for the fish"-message](http://groups.google.com/group/puppet-users/browse_thread/thread/83801a03c0fea665?pli=1):
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Date: Mon, 4 Apr 2011 19:26:06 +0200
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From: Nico -telmich- Schottelius <nico-puppet-users --at-- schottelius.org>
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To: puppet-users --at-- @googlegroups.com
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Cc: steven-puppet-users --at-- @armstrong.cc
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Subject: [Puppet Users] Migrating away from puppet to cdist
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Good morning puppet users,
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we, some sysadmins [0] at the computer science departement [1]
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at ETH Zurich [2], developed a new configuration management
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system called cdist [3], to which we migrate from our puppet
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configuration.
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I'm writing to this list for two reasons:
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1) Say thanks and goodbye to puppet-*
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Puppet in contrast to other systems emphasised on "define what I want"
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versus "define what todo", which is a great approach and we've
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shameless cloned this approach.
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Also we discussed a lot of ideas used in puppet (as well as other
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systems), from which we learned.
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Puppet was the first CM I seriously adopted and it initially saved
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me a lot of time. Thanks to the puppet team!
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2) Show other puppet users how to get around (common) puppet problems
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We're pretty confident that cdist solves some issues we've seen
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in puppet and in the sense of FOSS, we'd like to inform others
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how we've solved those issues in cdist:
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Bootstrap problem
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With puppet we needed to have ruby + some gems on the target
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hosts. In cdist we only use a posix shell on the target plus
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common UNIX tools (like find, rm, grep), as defined by POSIX.
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Complex CA / SSL setup / issues
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We've had some trouble using ssl certificates, especially with
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multi master and frequent reinstallations. In cdist we only
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rely on SSH.
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Defining configuration in multiple locations
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Defining a type multiple times in different locations in puppet
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requires use of virtual ressources. In cdist you don't need to
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care about this, as long as the parameters stay exactly the
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same.
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Error messages
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If you encountered errors like "400 Bad Request",
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"undefined method `closed?'", "can't convert nil into String",
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or "undefined method `closed?' for nil:NilClass", you'll be
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happy to hear that cdist's error messages contain usable
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information.
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Very easy extension
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Whereas puppet has modules, types and providers, cdist only knows
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about types. A type in cdist contains some functionality,
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independent of whether you or upstream decided to implement it.
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Pull versus Push approach
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Puppet requires one (or more for redundancy reasons) central server,
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because clients usually contact the master and ask for changes.
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Cdist operatas in push mode and can be run from a small machine
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like the sysadmin notebook.
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Integrated version control
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Cdist is usually cloned via git from upstream and changes are
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kept in a different git branch. This encourages you to use the
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existing version control for your own configuration.
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Integrated clean documentation
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All cdist documentation is included into the release and can be
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compiled into HTML or manpages. Cdist also includes a reference
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document that contains all available paths, types and environment
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variables.
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Unobstrusive upgrade path
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Upgrading cdist just requires one "git pull" on your master machine,
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no update needed on any client.
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Clean release cycle
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When in puppet things stopped to work within a minor version,
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the cdist release cycle clearly defines that any incompatibility
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forces a change on at least the minor (1.x -> 1.y) version.
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If you stay on a specific version, like 1.5, things will not break. Promised.
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No automatic (magic) behaviour
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In puppet you can use title or name without setting it explicitly.
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This may be useful in some parts, but maybe surprising as well.
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In cdist only the globally available environment variables are
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documented and have the same meaning everywhere.
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Codebase / Bugs
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Puppet contains around 100k lines of code, with cdist you only need
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to debug ~ 1k/2k lines (core/with types) lines of code
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(according to sloccount[5]).
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Age
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Warning: Although most pointers above may make cdist look like
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superior compared to puppet, cdist is still pretty young
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(~4 months old) and may lack some functionality puppet already has.
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cdist is usable in production environments already.
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It may just not work in very fancy or ancient environments.
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If you've any questions, do not hesitate to subscribe to the cdist
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mailing list [4] and ask them there.
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Cheers,
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Nico
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[0]: http://sans.ethz.ch
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[1]: http://www.inf.ethz.ch
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[2]: http://www.ethz.ch
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[3]: http://www.nico.schottelius.org/software/cdist/
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[4]: http://l.schottelius.org/mailman/listinfo/cdist
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[5]: http://www.dwheeler.com/sloccount/
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[[!tag config eth sysadmin unix]]
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