cdist/docs/man/man7/cdist-manifest.text

cdist-manifest(7)
=================
Nico Schottelius <nico-cdist--@--schottelius.org>


NAME
----
cdist-manifest - (Re-)Use types


DESCRIPTION
-----------
Manifests are used to define which objects to create.
Objects are instances of **types**, like in object orientated programming languages.
An object is represented by the combination of
**type + slash + object name**: **__file/etc/cdist-configured** is an
object of the type ***__file*** with the name ***etc/cdist-configured***.

All available types can be found in the **cdist/conf/type/** directory,
use **ls cdist/conf/type** to get the list of available types. If you have
setup the MANPATH correctly, you can use **man cdist-reference** to access
the reference with pointers to the manpages.


Types in manifests are used like normal command line tools. Let's have a look
at an example:
--------------------------------------------------------------------------------
# Create object of type __package with the parameter state = removed
__package apache2 --state removed

# Same with the __directory type
 __directory /tmp/cdist --state present
--------------------------------------------------------------------------------

These two lines create objects, which will later be used to realise the 
configuration on the target host.

Manifests are executed locally as a shell script using **/bin/sh -e**.
The resulting objects are stored in an internal database.

The same object can be redefined in multiple different manifests as long as
the parameters are exactly the same.

In general, manifests are used to define which types are used depending
on given conditions.


INITIAL AND TYPE MANIFESTS
--------------------------
Cdist knows about two types of manifests: The initial manifest and type
manifests. The initial manifest is used to define, which configurations
to apply to which hosts. The type manifests are used to create objects
from types. More about manifests in types can be found in cdist-type(7).


DEFINE STATE IN THE INITIAL MANIFEST
------------------------------------
The **initial manifest** is the entry point for cdist to find out, which
**objects** to configure on the selected host.
Cdist searches for the initial manifest at **cdist/conf/manifest/init**.

Within this initial manifest, you define, which objects should be
created on which host. To distinguish between hosts, you can use the
environment variable **__target_host**. Let's have a look at a simple
example:

--------------------------------------------------------------------------------
__cdistmarker

case "$__target_host" in
   localhost)
        __directory /home/services/kvm-vm --parents yes
   ;;
esac
--------------------------------------------------------------------------------

This manifest says: Independent of the host, always use the type 
***__cdistmarker***, which creates the file **/etc/cdist-configured**,
with the timestamp as content.
The directory ***/home/services/kvm-vm***, including all parent directories, 
is only created on the host ***localhost***.

As you can see, there is no magic involved, the manifest is simple shell code that
utilises cdist types. Every available type can be executed like a normal 
command.


SPLITTING UP THE INITIAL MANIFEST
---------------------------------
If you want to split up your initial manifest, you can create other shell
scripts in **cdist/conf/manifest/** and include them in **cdist/conf/manifest/init**.
Cdist provides the environment variable ***__manifest*** to reference to
the directory containing the initial manifest (see cdist-reference(7)).

The following example would include every file with a **.sh** suffix:

--------------------------------------------------------------------------------
# Include *.sh
for manifest in $__manifest/*.sh; do
    # And source scripts into our shell environment
    . "$manifest"
done
--------------------------------------------------------------------------------


DEPENDENCIES
------------
If you want to describe that something requires something else, just
setup the variable "require" to contain the requirements. Multiple
requirements can be added white space seperated.

--------------------------------------------------------------------------------
# No dependency
__file /etc/cdist-configured

# Require above object
require="__file/etc/cdist-configured" __link /tmp/cdist-testfile \
   --source /etc/cdist-configured  --type symbolic

# Require two objects
require="__file/etc/cdist-configured __link/tmp/cdist-testfile" \
   __file /tmp/cdist-another-testfile


--------------------------------------------------------------------------------

All objects that are created in a type manifest are automatically required
from the type that is calling them. This is called "autorequirement" in
cdist jargon.


EXAMPLES
--------
The initial manifest may for instance contain the following code:

--------------------------------------------------------------------------------
# Always create this file, so other sysadmins know cdist is used.
__file /etc/cdist-configured --type file

case "$__target_host" in
   my.server.name)
      __file /root/bin/ --type directory
      __file /etc/issue.net --type file --source "$__manifest/issue.net
   ;;
esac
--------------------------------------------------------------------------------

The manifest of the type "nologin" may look like this:

--------------------------------------------------------------------------------
__file /etc/nologin --type file --source "$__type/files/default.nologin"
--------------------------------------------------------------------------------


SEE ALSO
--------
- cdist-tutorial(7)
- cdist-type(7)


COPYING
-------
Copyright \(C) 2010-2012 Nico Schottelius. Free use of this software is
granted under the terms of the GNU General Public License version 3 (GPLv3).