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completly finish cdist-stages

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Signed-off-by: Nico Schottelius <nico@kr.ethz.ch>
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Nico Schottelius 2011-02-19 12:48:26 +01:00
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@ -5,77 +5,82 @@ Nico Schottelius <nico-cdist--@--schottelius.org>
NAME
----
cdist-stages - How the configuration is built
cdist-stages - Stages used during configuration deployment
DESCRIPTION
-----------
Starting the execution of deployment with cdist-deploy-to(1),
cdist passes through different stages, each can be triggered
and debugged on its own. Reading the source of the
cdist-deploy-to script shous the binaries being responsible
for each stage.
Starting the execution of deployment with cdist-deploy-to(1), cdist passes
through different stages, each can be triggered and debugged on its own.
Reading the source of the cdist-deploy-to executable shous the scripts
responsible for each stage.
STAGE 1: TARGET INFORMATION RETRIEVAL
--------------------------------------
In this stage information is collected about target using
so called explorers.
Every existing explorer is run on the target and the output
of all explorers are copied back into the local cache.
The results can be used by manifests and types.
In this stage information is collected about target using so called explorers.
Every existing explorer is run on the target and the output of all explorers
are copied back into the local cache. The results can be used by manifests and
types.
Related manpages are cdist-explorers(7) and cdist-cache(7).
STAGE 2: RUN THE INITIAL MANIFEST
---------------------------------
The initial manifest, which should be used for mappings
of hosts to types, is executed.
This stage creates objects in a cconfig database that
contains as defined in the manifest for the specific host.
In this stage, no conflicts may occur, i.e. no object of
the same type with the same id may be created.
The initial manifest, which should be used for mappings of hosts to types,
is executed. This stage creates objects in a cconfig database that contains
the objects as defined in the manifest for the specific host. In this stage,
no conflicts may occur, i.e. no object of the same type with the same id may
be created.
Related manpages are cdist-manifest-init(1), cdist-manifests(7) and
cdist-config-layout(7).
STAGE 3: EXECUTION OF TYPES
---------------------------
Every object is checked whether its type has an init
script (see cdist-types(7)). If the type of the object
has an init script, it is run. This init script may
generate additional objects.
Every object is checked whether its type has a manifest file. If the type has
a manifest file and it is executable, it will be executed. The manifest script
may generate and change the created objects. In other words, one type can reuse
other types.
For instance the object __apache/www.test.ch is of
type __apache, which may contain an init script, which
creates new objects of type __file.
For instance the object __apache/www.test.ch is of type __apache, which may
contain an manifest script, which creates new objects of type __file.
The newly created objects are merged back into the existing tree. No conflicts
may occur during the merge. A conflict would mean that two different objects
try to create the same object, which indicates a broken configuration.
Related manpage are cdist-types(7) and cdist-manifest-run-all(1).
The newly created objects are merged back into
the existing tree. No conflicts may occur during
the merge. A conflict would mean that two different
objects try to create the same object, which indicates a
broken configuration.
STAGE 4: CODE GENERATION
------------------------
The "gencode" binary of the types for every existing object is
called to generate code that will be executed on the target host.
In this stage for every created objects its type is checked whether it has a
gencode script. If the type has a gencode script and it is executable it will
be executed. This executable should create code to be executed on the target
on stdout. If the gencode executable fails, it must print diagnostic messages
on stderr and exit non-zero.
This binary should create code to be executed on the target on stdout.
Related manpages are cdist-types-gencode(7), cdist-gencode(1) and
cdist-gencode-all(1).
If the gencode binary fails, it must print diagnostic messages on stderr
and exit non-zero.
A description of what the generated code may/must/should
do can be found in cdist-types-gencode(7).
STAGE 5: CODE EXECUTION
-----------------------
The resulting code from the previous stage is transferred to the target host
and executed there to apply the configuration changes,
The resulting code is transferred to the target host and executed,
the run of cdist-deploy-to(1) ends.
Related manpages are cdist-exec-transfer(1) and cdist-exec-run(1).
SUMMARY
-------
If, and only if, all the stages complete without an errors, the configuration
will be applied to the target. Each stage can also be run individually, though
dependencies for each stage must be fulfilled and thus the stages must be run
in correct order.
SEE ALSO