[pbs-devel] [PATCH proxmox-backup] docs: add external metrics server page

[Gabriel Goller]

Add External Metrics page to PBS's documentation. Most of it is copied
from the PVE documentation, minus the Graphite part.

Signed-off-by: Gabriel Goller <g.goller at proxmox.com>
---
 docs/external_metric_server.rst | 57 +++++++++++++++++++++++++++++++++
 docs/sysadmin.rst               |  2 ++
 2 files changed, 59 insertions(+)
 create mode 100644 docs/external_metric_server.rst

diff --git a/docs/external_metric_server.rst b/docs/external_metric_server.rst
new file mode 100644
index 000000000000..5dd36ea5b7e5
--- /dev/null
+++ b/docs/external_metric_server.rst
@@ -0,0 +1,57 @@
+.. _external_metric_server:
+
+External Metric Server
+----------------------
+
+In Proxmox Backup, you can define external metric servers, which will
+periodically receive various stats about your host's memory, network, and disk
+activity.
+
+Currently supported are:
+
+ * InfluxDB (HTTP) (see https://docs.influxdata.com/influxdb/v2/ )
+ * InfluxDB (UDP) (see https://docs.influxdata.com/influxdb/v1/ )
+
+The external metric server definitions are saved in
+'/etc/proxmox-backup/metricserver.cfg', and can be edited through the web
+interface.
+
+.. note::
+
+   UDP support has been dropped in InfluxDB v2, so HTTP use is recommended.
+
+InfluxDB (HTTP) plugin configuration
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+The plugin can be configured to use the HTTP(s) API of InfluxDB 2.x.
+InfluxDB 1.8.x does contain a forwards compatible API endpoint for this v2 API.
+
+Since InfluxDB's v2 API is only available with authentication, you have
+to generate a token that can write into the correct bucket and set it.
+
+In the v2 compatible API of 1.8.x, you can use 'user:password' as token
+(if required), and can omit the 'organization' since that has no meaning in InfluxDB 1.x.
+
+You can also set the maximum batch size (default 25000000 bytes) with the
+'max-body-size' setting (this corresponds to the InfluxDB setting with the
+same name).
+
+InfluxDB (UDP) plugin configuration
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Proxmox Backup can also send the data over UDP, but the InfluxDB server has to
+be configured for this. The MTU can also be configured here, if necessary.
+
+Here is an example configuration for InfluxDB (on your InfluxDB server):
+
+----
+[[udp]]
+   enabled = true
+   bind-address = "0.0.0.0:8089"
+   database = "proxmox"
+   batch-size = 1000
+   batch-timeout = "1s"
+----
+
+With this configuration, your server listens on all IP addresses on port 8089,
+and writes the data in the *proxmox* database.
diff --git a/docs/sysadmin.rst b/docs/sysadmin.rst
index 114ad4cbbe0e..d42b6a9b2af1 100644
--- a/docs/sysadmin.rst
+++ b/docs/sysadmin.rst
@@ -30,6 +30,8 @@ please refer to the standard Debian documentation.
 
 .. include:: certificate-management.rst
 
+.. include:: external_metric_server.rst
+
 .. include:: services.rst
 
 .. include:: command-line-tools.rst
-- 
2.39.2