72 lines
2.5 KiB
ReStructuredText
72 lines
2.5 KiB
ReStructuredText
Why should I use cdist?
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=======================
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There are several motivations to use cdist, these
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are probably the most popular ones.
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Known language
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--------------
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Cdist is being configured in
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`shell script <https://en.wikipedia.org/wiki/Shell_script>`_.
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Shell script is used by UNIX system engineers for decades.
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So when cdist is introduced, your staff does not need to learn a new
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`DSL <https://en.wikipedia.org/wiki/Domain-specific_language>`_
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or programming language.
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Powerful language
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-----------------
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Not only is shell scripting widely known by system engineers,
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but it is also a very powerful language. Here are some features
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which make daily work easy:
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* Configuration can react dynamically on explored values
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* High level string manipulation (using sed, awk, grep)
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* Conditional support (**if, case**)
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* Loop support (**for, while**)
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* Support for dependencies between cdist types
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More than shell scripting
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-------------------------
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If you compare regular shell scripting with cdist, there is one major
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difference: When using cdist types,
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the results are
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`idempotent <https://en.wikipedia.org/wiki/Idempotence>`_.
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In practise that means it does not matter in which order you
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call cdist types, the result is always the same.
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Zero dependency configuration management
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----------------------------------------
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Cdist requires very little on a target system. Even better,
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in almost all cases all dependencies are usually fulfilled.
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Cdist does not require an agent or high level programming
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languages on the target host: it will run on any host that
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has a **ssh server running** and a POSIX compatible shell
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(**/bin/sh**). Compared to other configuration management systems,
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it does not require to open up an additional port.
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Push based distribution
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-----------------------
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Cdist uses the push based model for configuration. In this
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scenario, one (or more) computers connect to the target hosts
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and apply the configuration. That way the source host has
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very little requirements: Cdist can even run on a sysadmin
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notebook that is loosely connected to the network and has
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limited amount of resources.
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Furthermore, from a security point of view, only one machine
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needs access to the target hosts. No target hosts will ever
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need to connect back to the source host, which contains the
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full configuration.
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Highly scalable
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---------------
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If at some point you manage more hosts than can be handled from
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a single source host, you can simply add more resources: Either
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add more cores to one host or add hosts.
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Cdist will utilise the given resources in parallel.
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