RPi-Monitor: Version 2.x advance usage and customization

Edit: RPi-Monitor version 2.7 introduce a change in configuration name and location:

• /etc/rpimonitor d.conf becomes /etc/rpimonitor/daemon.conf
• /etc/rpimonitord.conf.d becomes /etc/rpimonitor/data.conf
• /etc/rpimonitord.conf.d/*.conf becomes /etc/rpimonitor/*.conf

In this article we will see how to do the things described in RPi-Monitor: Advance usage and customization and maybe, a little bit more...

We will then answer the same questions : How should I do if I want to...

• Customize RPi-Monitor v2.x to fit a particular needs?
• Use it with my own Web Server? 
• Add "friends" linking RPi-Monitor v2.x running on different platform together?
• Use it into another Linux distribution than Raspbian? 
• Add other graphs from additional sources (other mount point or external temperature probe)?

Photo from Flickr  cc-by-nc-sa by blogjunkie

Note: A prerequisite is to install the latest version of RPi-Monitor v2.x
Customize RPi-Monitor v2.x to fit a particular needs

If you want to customize RPi-Monitor in a way not described bellow you just have to know 2 things:

You will find bellow some example of customization showing you the capababilities of RPi-Monitor v2.x

In this example I will use nginx server. You could use the same tactic with your preferred web server.

Let's first update the configuration file to disable the embedded web server. Edit the file /etc/rpimonitord.conf and set daemon.noserver=1.

Then restart RPi-Monitor with the command:
    sudo service rpimonitor restart

The embedded server is no more running so, we will need to configure another server to access the data.

For nginx we will create the file /etc/nginx/sites-enabled/rpimonitor with the following content:

server {     listen 80;     index index.html;     root /usr/share/rpimonitor/web; }

To go further, you can read the article RPi-Monitor: Build a multi-sites SSL certificate to improve user experience.


Add "friends" linking RPi-Monitor running on different platform together

Friends is a notion that comes in version 1.2. A friend is simply another computer running RPi-Monitor. Configuring friends will add a drop down list on the right of the top menu with a links to RPi-Monitor sitting on the other computer.

Friends menu is visible on the top right

In /etc/rpimonitord.conf.d/default.conf, each friend is identified by its and is described by the 2 following parameters:

Here is an example of configuration for 3 friends:

web.friends.1.name=Raspberry Pi web.friends.1.link=http://192.168.0.123/ web.friends.2.name=Shuttle web.friends.2.link=http://192.168.0.2/ web.friends.3.name=Laptop web.friends.3.link=http://192.168.0.38/

RPi-Monitor has been designed to run into a Raspberry Pi but as it is using only standard Linux resources, it is not hardware dependent. A simple configuration update can make it run on Ubuntu, CentOS or any other distribution.

Ubuntu is a Debian based distribution as Raspbian. The installation can then be done using the deb package available for each releases. Download and install the package as described in this previous post.

With CentOS and withe any non Debian based distribution it will required to perform a manual installation.
First install the perl dependencies: HTTP::Daemon (perl-libwww-perl), RRD (rrdtool-perl) and JSON(perl-JSON)

Connect to github and select the latest stable branch on the top left dropdown list.
Then download the code as zip file from the link "Download zip" visible at the bottom of the right menu.

Unpack it.
    unzip Version-2.x.zip

Finally install rpimonitor manually:
    su -
    mv Version-2.x/rpimonitor /usr/local

You can now start RPi-Monitor with the following commands:
    cd /usr/local/rpimonitor
    ./rpimonitird -c rpimonitor.conf -c default.conf

Note: I will not describe here how to configure the auto startup since each distribution has its own way to do so. An upstart script is available into RPi-Monitor github tools directory, it may help you in such an action.


Once the installation is done you can start RPi-Monitor and connect to it with your favorite browser.
You may notice that some values are undefined or displayed as NaN (Not a Number). To fix these issues, you will have to update the configuration file (rpimonitord.conf or default.conf in /etc/ + /etc/rpimonitord.conf.d or /usr/local/rpimonitor/ depending on your installation).

CentOS 6.3 before configuration file customisation

Add other graphs from additional sources: other mount point

For this section we will take the example of an additional disk on sda as described previous article  RPi-Monitor: Advance usage and customization.

The disk have a disk with two partition /dev/sda1 and /dev/sda3.
The command and regular expression will be the following:

• sda1 disk size command : df -t ext2,  regular expression: sda1\s+(\d+)
• sda1 used space command : df -t ext2,  regular expression: sda1\s+\d+\s+(\d+)
• sda3 disk size command : df -t ext4,  regular expression: sda3\s+(\d+)
• sda3 used space command : df -t ext4,  regular expression: sda3\s+\d+\s+(\d+)

First we need to configure the extraction of partitions sizes which are extracted once at RPi-Monitor startup. We will create a file /etc/rpimonitord.conf.d/custo.conf with the data configured as static data like this:

static.10.name=storage1_total static.10.source=df -t ext2 static.10.regexp=sda1\s+(\d+) static.10.postprocess=$1/1024 static.11.name=storage2_total static.11.source=df -t ext4 static.11.regexp=sda3\s+(\d+) static.11.postprocess=$1/1024

The id of the KPIs start at 10 since in my configuration files the previous KPI was 9. This comment is the same for next ids.
The post processing is configured to transform kB into MB by dividing the extracted result by 1024.

For dynamic values extracted every 10 seconds, the configuration will be:

dynamic.14.name=storage1_used dynamic.14.source=df -t ext2 dynamic.14.regexp=sda1\s+\d+\s+(\d+) dynamic.14.postprocess=$1/1024 dynamic.14.rrd=GAUGE dynamic.15.name=storage2_used dynamic.15.source=df -t ext4 dynamic.15.regexp=sda3\s+\d+\s+(\d+) dynamic.15.postprocess=$1/1024 dynamic.15.rrd=GAUGE

Dynamic stat will be stored into a RRD File as GAUGE. Ref to RRDTool help for detail about Data Source Types.

Disk icon has been found here

This icons has to be installed into the img directory of RPi-Monitor which is by default /usr/share/rpimonitor/web/img/.

The configuration to add a new status strip will then be the following:
    

web.status.1.content.9.name=Storage web.status.1.content.9.icon=usb_hdd.png web.status.1.content.9.line.1="<b>/storage1</b> Used: <b>"+KMG(data.storage1_used,'M')+"</b> (<b>"+Percent(data.storage1_used,data.storage1_total,'M')+"</b>) Free: <b>"+KMG(data.storage1_total-data.storage1_used,'M')+ "</b> Total: <b>"+ KMG(data.storage1_total,'M') +"</b>" web.status.1.content.9.line.2=ProgressBar(data.storage1_used,data.storage1_total) web.status.1.content.9.line.3="<b>/storage2</b> Used: <b>"+KMG(data.storage2_used,'M')+"</b> (<b>"+Percent(data.storage2_used,data.storage2_total,'M')+"</b>) Free: <b>"+KMG(data.storage2_total-data.storage2_used,'M')+ "</b> Total: <b>"+ KMG(data.storage2_total,'M') +"</b>"

The configuration may need some explanation:
We do configure 4 lines. Each line is describing a javascript line using some predefined functions: KMG, Precent and ProgressBar. This function are called by the browser while rendering the page. Some variable coming from the extracted data are also used. These variables are starting by the keyword 'data.'. For deeper detail about this configuration execute the command man rpimonitord.conf

To see our modification we need to restart RPi-Monitor and refresh the statistics page into our browser.
    sudo  service rpimonitor restart

The result of the configuration is at the bottom of the following screenshot:



The status page is working, let's now add a graphic of the disk usage. This is done with the following configuration:

web.statistics.1.content.9.name=Storage1 web.statistics.1.content.9.graph.1=storage1_total web.statistics.1.content.9.graph.2=storage1_used web.statistics.1.content.9.ds_graph_options.storage1_total.label=Storage1 total space (MB) web.statistics.1.content.9.ds_graph_options.storage1_total.color="#FF7777" web.statistics.1.content.9.ds_graph_options.storage1_used.label=Storage1 used space (MB) web.statistics.1.content.9.ds_graph_options.storage1_used.lines={ fill: true } web.statistics.1.content.9.ds_graph_options.storage1_used.color="#7777FF" web.statistics.1.content.10.name=Storage2 web.statistics.1.content.10.graph.1=storage2_total web.statistics.1.content.10.graph.2=storage2_used web.statistics.1.content.10.ds_graph_options.storage2_total.label=Storage2 total space (MB) web.statistics.1.content.10.ds_graph_options.storage2_total.color="#FF7777" web.statistics.1.content.10.ds_graph_options.storage2_used.label=Storage2 used space (MB) web.statistics.1.content.10.ds_graph_options.storage2_used.lines={ fill: true } web.statistics.1.content.10.ds_graph_options.storage2_used.color="#7777FF"

The configuration may also need some explanation
We do configure 2 graphs each having 2 curves. The first curve represent the total and is using static data extracted previously. This curve will be represented as a light red line.
The second curve is representing the usage of disk and is represented as a light blue line filled. The parameters defining the curve are define by the keyword ds_graph_options. Details of this parameter can be found in javascriptrrd help page. Restart rpimonitor to activate the new graph.

After waiting a little time to let the system extract data you will see this kind of graph.

Add other graphs from additional sources: external temperature probe

Let's build a little electronic device to measure the room temperature and add this in the temperature graph.
Do do that, you will need:

• 1 x DS18B20
• 1 x 4.7k resistor

Plug them as described in the following schema extracted from Adafruit Lesson 11:


Lets first load the kernel module required to get the information from this probe:
    sudo modprobe gpio
    sudo modprobe w1-gpio

    sudo modprobe w1-therm

First we have to identify the id of our probe:
    ls /sys/bus/w1/devices/
    28-000004fe1847  w1_bus_master1
the id is: 28-000004fe1847. Let's now check if we can get the temperature:
    cat /sys/bus/w1/devices/28-000004fe1847/w1_slave
    5a 01 4b 46 7f ff 06 10 a3 : crc=a3 YES
    5a 01 4b 46 7f ff 06 10 a3 t=21625