When enabling telegraf, task failed with "the field 'vars' has an invalid value,
which appears to include a variable that is undefined. The error was: 'dict
object' has no attribute 'telegraf_services'"

Change-Id: I6dd5c401bf9b673685ad1b4a20f85c55ce04abbc
Closes-bug: #1662807

Change-Id: Ia658b0774ce009feb6b4e73363114f7922833835
Partially-implements: blueprint better-reconfigure

Added mysql plugin for telegraf to be used by default.
Plugin gathers the statistic data from MySQL server.

Change-Id: I853af61b64739eedb70ab2b8dc78f0285a839671
Closes-Bug: #1652609

* Merge prechecks.yml and site.yml playbook
* Create empty precheck.yml into all roles.

Change-Id: I8a138558a26c0a2a66c5fd48ed37be657c99c1dd
Implements: blueprint condition-pre-check

HAProxy stats pages are used to gather performance metrics from HAProxy.

Change-Id: I999fcd0785d90c1be0b760fd6cd8804399d5a94c
Closes-bug: #1634227

Change-Id: Ifa72d352e65c834afa078a7b08a7582155e6298b
Closes-bug: #1635032

It makes no sense to monitor the filestats of local logfiles.

TrivialFix

Change-Id: I5ef060b57d2c88f922a05c59556ff5c96929f871

Change-Id: If906f9a125f2fe11d1deb7eea5af4bcea3feac18
Partial-Bug: #1631503

do_reconfigure.yml is introduced to use serial directive. But we use
it in wrong. Now serial has moved to playbook file. So it is time to
remove the do_reconfigure.yml file

Closes-Bug: #1628152
Change-Id: I8d42d27e6bc302a0e575b0353956eaef9b2ca9fd

Added ansible role to deploy telegraf

Roll out telegraf to all nodes

Introduce parameter to toggle deployment of performance monitoring

Co-Authored-By: zhubingbing <zhubingbing10@gmail.com>

Change-Id: Ia09b20ce65bf557c1a1030eda99df5cc88debd01
Partially-Implements: Blueprint performance-monitoring