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