docs update

docs/telegraf.rst

@@ -8,13 +8,152 @@ It is not the purpose of this documentation to expose every piece of the install
 Telegraf installation and configuration
 =======================================
 
-Telegraf installation, configuration and start
-----------------------------------------------
+Telegraf standard installation (standalone and independant process)
+-------------------------------------------------------------------
 
 The installation of Telegraf is really straightforward, consult:
 
 - https://github.com/influxdata/telegraf
 
+If you wish to deploy Telegraf as a Splunk TA application instead, consult the next step.
+
+Telegraf deployment as Splunk application deployed by Splunk (TA)
+-----------------------------------------------------------------
+
+For Linux OS only (this does not work on Windows), you can publish Telegraf through a Splunk application that you push to your clients using a Splunk deployment server.
+
+This means that you can create a custom Technology Addon (TA) that contains both the Telegraf binary and the telegraf.conf configuraton files.
+
+**This method has several advantages:**
+
+- If you are a Splunk customer already, you may have the Splunk Universal Forwarder deployed on your servers, you will NOT need to deploy an additional collector independently from Splunk
+
+- You get benefit from the Splunk centralisation and deploy massively Telegraf from Splunk
+
+- You can maintain and upgrade Telegraf just as you do usually in Splunk, all from your Splunk Deployment Server. (DS)
+
+**If you wish to check for a read to use example, see:**
+
+- https://github.com/guilhemmarchand/TA-telegraf-amd64
+
+**To achieve this, you need to:**
+
+- Create a package in your Splunk Deployment Server, let's call it "TA-telegraf-linux-amd64", if you have more than this architecture to maintain, just reproduce the same steps for other processor architectures. (arm, etc)
+
+::
+
+    $SPLUNK_HOME/etc/deployment-server/TA-telegraf-linux-amd64
+                                                        /bin
+                                                        /local/telegraf.conf
+                                                        /metadata/default.meta
+
+- The "bin" directory hosts the Telegraf binary
+
+- The "local" directory hosts the telegraf.conf configuration file
+
+- The "metadata" directory is a standard directory that should contain a default.meta which in the context of the TA will contain:
+
+*default.meta*
+
+::
+
+    # Application-level permissions
+    []
+    owner = admin
+    access = read : [ * ], write : [ admin ]
+    export = system
+
+- Download the last Telegraf version for your processor architecture (here amd64), and extract its contain in the "bin" directory, you will get:
+
+::
+
+    bin/telegraf/etc
+    bin/telegraf/usr
+    bin/telegraf/var
+
+- Telegraf provides an "init.sh" script that we will use to manage the state of the Telegraf process:
+
+::
+
+    bin/telegraf/usr/lib/telegraf/scripts/init.sh
+
+- Copy this "init.sh" script to the root of the "bin" directory:
+
+::
+
+    cp -p bin/telegraf/usr/lib/telegraf/scripts/init.sh bin/
+
+- Achieve some minor modifications related to patch customizations, basically:
+
+Change:
+
+::
+
+    USER=telegraf
+    GROUP=telegraf
+
+By:
+
+::
+
+    USER=$(whoami)
+    GROUP=$(id -g -n)
+
+*Notes: the configuration above will automatically use the owner of the Splunk processes*
+
+Change:
+
+::
+
+    daemon=/usr/bin/telegraf
+
+By:
+
+::
+
+    daemon=$SPLUNK_HOME/etc/apps/TA-telegraf-amd64/bin/telegraf/usr/bin/telegraf
+
+Change:
+
+::
+
+    config=/etc/telegraf/telegraf.conf
+    confdir=/etc/telegraf/telegraf.d
+
+By:
+
+::
+
+    config=$SPLUNK_HOME/etc/apps/TA-telegraf-amd64/local/telegraf.conf
+    confdir=$SPLUNK_HOME/etc/apps/TA-telegraf-amd64/bin/telegraf/etc/telegraf/telegraf.d
+
+
+**Finally, create a very simple local/inputs.conf configuration file:**
+
+*local/inputs.conf*
+
+::
+
+    # start telegraf at Splunk start, and restart if Splunk is restarted. (which allows upgrading easily Telegraf binaries shipped with the TA package)
+    [script://./bin/init.sh restart]
+    disabled = false
+    interval = -1
+
+Et voila ! Deploy this TA to your Linux host and start receiving metrics in Splunk.
+
+If you wish to check for a read to use example, see:
+
+- https://github.com/guilhemmarchand/TA-telegraf-amd64
+
+**Upgrades:**
+
+To upgrade Telegraf binary to a new version, simply extract the new tgz release in the "bin" directory, and reload your Splunk Deployment server.
+
+Splunk will automatically restart the Telegraf process after Splunk startup.
+
+Telegraf minimal configuration
+------------------------------
+
 A minimal configuration to monitor Operating System metrics:
 
 - https://docs.influxdata.com/chronograf/latest/guides/using-precreated-dashboards/#system
@@ -182,7 +321,7 @@ Windows DFS server
 - https://github.com/influxdata/telegraf/tree/master/plugins/inputs/win_perf_counters#dfs-replication--domain-controllers
 
 Microsoft IIS / ASP.NET
-------------------
+-----------------------
 
 **For IIS and ASP.NET, follow instructions for: IIS / ASP.NET**