Adding upstream version 18.2.2.upstream/18.2.2

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 99 insertions, 0 deletions

diff --git a/doc/start/intro.rst b/doc/start/intro.rst
new file mode 100644
index 000000000..3a50a8733
--- /dev/null
+++ b/doc/start/intro.rst
@@ -0,0 +1,99 @@
+===============
+ Intro to Ceph
+===============
+
+Ceph can be used to provide :term:`Ceph Object Storage` to :term:`Cloud
+Platforms` and Ceph can be used to provide :term:`Ceph Block Device` services
+to :term:`Cloud Platforms`. Ceph can be used to deploy a :term:`Ceph File
+System`.  All :term:`Ceph Storage Cluster` deployments begin with setting up
+each :term:`Ceph Node` and then setting up the network. 
+
+A Ceph Storage Cluster requires the following: at least one Ceph Monitor and at
+least one Ceph Manager, and at least as many Ceph OSDs as there are copies of
+an object stored on the Ceph cluster (for example, if three copies of a given
+object are stored on the Ceph cluster, then at least three OSDs must exist in
+that Ceph cluster). 
+
+The Ceph Metadata Server is necessary to run Ceph File System clients.
+
+.. note::
+
+   It is a best practice to have a Ceph Manager for each Monitor, but it is not
+   necessary. 
+
+.. ditaa::
+
+            +---------------+ +------------+ +------------+ +---------------+
+            |      OSDs     | | Monitors   | |  Managers  | |      MDSs     |
+            +---------------+ +------------+ +------------+ +---------------+
+
+- **Monitors**: A :term:`Ceph Monitor` (``ceph-mon``) maintains maps
+  of the cluster state, including the monitor map, manager map, the
+  OSD map, the MDS map, and the CRUSH map.  These maps are critical 
+  cluster state required for Ceph daemons to coordinate with each other.  
+  Monitors are also responsible for managing authentication between 
+  daemons and clients.  At least three monitors are normally required 
+  for redundancy and high availability.
+
+- **Managers**: A :term:`Ceph Manager` daemon (``ceph-mgr``) is
+  responsible for keeping track of runtime metrics and the current
+  state of the Ceph cluster, including storage utilization, current
+  performance metrics, and system load.  The Ceph Manager daemons also
+  host python-based modules to manage and expose Ceph cluster
+  information, including a web-based :ref:`mgr-dashboard` and
+  `REST API`_.  At least two managers are normally required for high
+  availability.
+
+- **Ceph OSDs**: An Object Storage Daemon (:term:`Ceph OSD`,
+  ``ceph-osd``) stores data, handles data replication, recovery,
+  rebalancing, and provides some monitoring information to Ceph
+  Monitors and Managers by checking other Ceph OSD Daemons for a
+  heartbeat. At least three Ceph OSDs are normally required for 
+  redundancy and high availability.
+
+- **MDSs**: A :term:`Ceph Metadata Server` (MDS, ``ceph-mds``) stores
+  metadata on behalf of the :term:`Ceph File System` (i.e., Ceph Block
+  Devices and Ceph Object Storage do not use MDS). Ceph Metadata
+  Servers allow POSIX file system users to execute basic commands (like
+  ``ls``, ``find``, etc.) without placing an enormous burden on the
+  Ceph Storage Cluster.
+
+Ceph stores data as objects within logical storage pools. Using the
+:term:`CRUSH` algorithm, Ceph calculates which placement group (PG) should
+contain the object, and which OSD should store the placement group.  The
+CRUSH algorithm enables the Ceph Storage Cluster to scale, rebalance, and
+recover dynamically.
+
+.. _REST API: ../../mgr/restful
+
+.. container:: columns-2
+
+   .. container:: column
+
+      .. raw:: html
+
+          <h3>Recommendations</h3>
+
+      To begin using Ceph in production, you should review our hardware
+      recommendations and operating system recommendations.
+
+      .. toctree::
+         :maxdepth: 2
+
+         Hardware Recommendations <hardware-recommendations>
+         OS Recommendations <os-recommendations>
+
+   .. container:: column
+
+      .. raw:: html
+
+          <h3>Get Involved</h3>
+
+      You can avail yourself of help or contribute documentation, source
+      code or bugs by getting involved in the Ceph community.
+
+      .. toctree::
+         :maxdepth: 2
+
+         get-involved
+         documenting-ceph