initial code repo

This patch creates initial code repo.

For ceph, luminous stable release will be used for base code,
and next changes and optimization for ceph will be added to it.

For opensds, currently any changes can be upstreamed into original
opensds repo (https://github.com/opensds/opensds), and so stor4nfv
will directly clone opensds code to deploy stor4nfv environment.
And the scripts for deployment based on ceph and opensds will be
put into 'ci' directory.

Change-Id: I46a32218884c75dda2936337604ff03c554648e4
Signed-off-by: Qiaowei Ren <qiaowei.ren@intel.com>

1 files changed, 215 insertions, 0 deletions

diff --git a/src/ceph/doc/mgr/plugins.rst b/src/ceph/doc/mgr/plugins.rst
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+
+ceph-mgr plugin author guide
+============================
+
+Creating a plugin
+-----------------
+
+In pybind/mgr/, create a python module.  Within your module, create a class
+named ``Module`` that inherits from ``MgrModule``.
+
+The most important methods to override are:
+
+* a ``serve`` member function for server-type modules.  This
+  function should block forever.
+* a ``notify`` member function if your module needs to
+  take action when new cluster data is available.
+* a ``handle_command`` member function if your module
+  exposes CLI commands.
+
+Installing a plugin
+-------------------
+
+Once your module is present in the location set by the
+``mgr module path`` configuration setting, you can enable it
+via the ``ceph mgr module enable`` command::
+
+  ceph mgr module enable mymodule
+
+Note that the MgrModule interface is not stable, so any modules maintained
+outside of the Ceph tree are liable to break when run against any newer
+or older versions of Ceph.
+
+Logging
+-------
+
+MgrModule instances have a ``log`` property which is a logger instance that
+sends log messages into the Ceph logging layer where they will be recorded
+in the mgr daemon's log file.
+
+Use it the same way you would any other python logger.  The python
+log levels debug, info, warn, err are mapped into the Ceph
+severities 20, 4, 1 and 0 respectively.
+
+Exposing commands
+-----------------
+
+Set the ``COMMANDS`` class attribute of your plugin to a list of dicts
+like this::
+
+    COMMANDS = [
+        {
+            "cmd": "foobar name=myarg,type=CephString",
+            "desc": "Do something awesome",
+            "perm": "rw"
+        }
+    ]
+
+The ``cmd`` part of each entry is parsed in the same way as internal
+Ceph mon and admin socket commands (see mon/MonCommands.h in
+the Ceph source for examples)
+
+Config settings
+---------------
+
+Modules have access to a simple key/value store (keys and values are
+byte strings) for storing configuration.  Don't use this for
+storing large amounts of data.
+
+Config values are stored using the mon's config-key commands.
+
+Hints for using these:
+
+* Reads are fast: ceph-mgr keeps a local in-memory copy
+* Don't set things by hand with "ceph config-key", the mgr doesn't update
+  at runtime (only set things from within modules).
+* Writes block until the value is persisted, but reads from another
+  thread will see the new value immediately.
+
+Any config settings you want to expose to users from your module will
+need corresponding hooks in ``COMMANDS`` to expose a setter.
+
+Accessing cluster data
+----------------------
+
+Modules have access to the in-memory copies of the Ceph cluster's
+state that the mgr maintains.  Accessor functions as exposed
+as members of MgrModule.
+
+Calls that access the cluster or daemon state are generally going
+from Python into native C++ routines.  There is some overhead to this,
+but much less than for example calling into a REST API or calling into
+an SQL database.
+
+There are no consistency rules about access to cluster structures or
+daemon metadata.  For example, an OSD might exist in OSDMap but
+have no metadata, or vice versa.  On a healthy cluster these
+will be very rare transient states, but plugins should be written
+to cope with the possibility.
+
+``get(self, data_name)``
+
+Fetch named cluster-wide objects such as the OSDMap.  Valid things
+to fetch are osd_crush_map_text, osd_map, osd_map_tree,
+osd_map_crush, config, mon_map, fs_map, osd_metadata, pg_summary,
+df, osd_stats, health, mon_status.
+
+All these structures have their own JSON representations: experiment
+or look at the C++ dump() methods to learn about them.
+
+``get_server(self, hostname)``
+
+Fetch metadata about a particular hostname.  This is information
+that ceph-mgr has gleaned from the daemon metadata reported
+by daemons running on a particular server.
+
+``list_servers(self)``
+
+Like ``get_server``, but gives information about all servers (i.e. all
+unique hostnames that have been mentioned in daemon metadata)
+
+``get_metadata(self, svc_type, svc_id)``
+
+Fetch the daemon metadata for a particular service.  svc_type is one
+of osd or mds, and svc_id is a string (convert OSD integer IDs to strings
+when calling this).
+
+``get_counter(self, svc_type, svc_name, path)``
+
+Fetch the latest performance counter data for a particular counter.  The
+path is a period-separated concatenation of the subsystem and the counter
+name, for example "mds.inodes".
+
+A list of two-tuples of (timestamp, value) is returned.  This may be
+empty if no data is available.
+
+Sending commands
+----------------
+
+A non-blocking facility is provided for sending monitor commands
+to the cluster.
+
+``send_command(self, result, command_str, tag)``
+
+The ``result`` parameter should be an instance of the CommandResult
+class, defined in the same module as MgrModule.  This acts as a
+completion and stores the output of the command.  Use CommandResult.wait()
+if you want to block on completion.
+
+The ``command_str`` parameter is a JSON-serialized command.  This
+uses the same format as the ceph command line, which is a dictionary
+of command arguments, with the extra ``prefix`` key containing the
+command name itself.  Consult MonCommands.h for available commands
+and their expected arguments.
+
+The ``tag`` parameter is used for nonblocking operation: when
+a command completes, the ``notify()`` callback on the MgrModule
+instance is triggered, with notify_type set to "command", and
+notify_id set to the tag of the command.
+
+Implementing standby mode
+-------------------------
+
+For some modules, it is useful to run on standby manager daemons as well
+as on the active daemon.  For example, an HTTP server can usefully
+serve HTTP redirect responses from the standby managers so that
+the user can point his browser at any of the manager daemons without
+having to worry about which one is active.
+
+Standby manager daemons look for a class called ``StandbyModule``
+in each module.  If the class is not found then the module is not
+used at all on standby daemons.  If the class is found, then
+its ``serve`` method is called.  Implementations of ``StandbyModule``
+must inherit from ``mgr_module.MgrStandbyModule``.
+
+The interface of ``MgrStandbyModule`` is much restricted compared to
+``MgrModule`` -- none of the Ceph cluster state is available to
+the module.  ``serve`` and ``shutdown`` methods are used in the same
+way as a normal module class.  The ``get_active_uri`` method enables
+the standby module to discover the address of its active peer in
+order to make redirects.  See the ``MgrStandbyModule`` definition
+in the Ceph source code for the full list of methods.
+
+For an example of how to use this interface, look at the source code
+of the ``dashboard`` module.
+
+Logging
+-------
+
+Use your module's ``log`` attribute as your logger.  This is a logger
+configured to output via the ceph logging framework, to the local ceph-mgr
+log files.
+
+Python log severities are mapped to ceph severities as follows:
+
+* DEBUG is 20
+* INFO is 4
+* WARN is 1
+* ERR is 0
+
+Shutting down cleanly
+---------------------
+
+If a module implements the ``serve()`` method, it should also implement
+the ``shutdown()`` method to shutdown cleanly: misbehaving modules
+may otherwise prevent clean shutdown of ceph-mgr.
+
+Is something missing?
+---------------------
+
+The ceph-mgr python interface is not set in stone.  If you have a need
+that is not satisfied by the current interface, please bring it up
+on the ceph-devel mailing list.  While it is desired to avoid bloating
+the interface, it is not generally very hard to expose existing data
+to the Python code when there is a good reason.
+