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