Wendelin - HowTo setup Fluentd on Sensor

Select the machine on which you want to supply Fluentd.

Wait until the compilation process has been finished.

First find the reference of your Streaming Device.

It is located in your Slapos Dashboard in Servers tab.

Then using supply command of Slapos Client install Fluentd software release on that computer.

supply("https://lab.nexedi.com/nexedi/slapos/raw/master/software/fluentd/software.cfg", "YOUR_COMPUTER_ID")

About Fluentd configuration file you can learn from here.

For input plugin we use Fluentd's standard exec plugin. 

The plugin will execute the python script we wrote in HowTo Setup Sensor and IOT Gateway to read sensor data every minute. 

For output plugin we use Fluentd's standard forward plugin.

YOUR_TAG_NAME - it must consist of two part separated by .(dot). For example sensor_1.sample-environment-raw-data. First part (sensor_1) is the name of the sensor and must be the same as the reference of the Data Supply we created in HowTo Create Data Supply tutorial. The second part (sample-environment-raw-data) is the type of data (Data Product  -  HowTo Create Data Product).

host - IPV6 address of your server where data will be sent. In our case it will be the address of  IOT Gateway. 

Click on the add button.

Select the machine on which you previously supplied Fluentd by clicking on the Computer Node drop-down list. This is the machine on which the instance will be requested.

Fill in the Fluentd configuration parameters in the Instance Parameter field. You can use the <parameter> tag to specify certain parameters of your instance. The name for the Fluentd configuration parameter is conf_text. Because the Instance Parameter itself is written in XML we have to escape our Fluentd Configuration File. You can use an Online XML escape tool (for instance appdevtools).

The escaped form of the configuration would be something similar to:

<?xml version="1.0" encoding="utf-8" ?><instance>
<parameter id="conf_text">&lt;source&gt;
  @type exec
  tag YOUR_TAG_NAME
  command  python3 /usr/local/bin/custom_read_bme280.py
  run_interval 1m
  &lt;parse&gt;
    keys pressure, humidity, temperature
  &lt;/parse&gt;
&lt;/source&gt;
&lt;match YOUR_TAG_NAME&gt;
  @type forward
  &lt;server&gt;
   name myserver1
   host IPV6_ADDRESS_OF_YOUR_IOT_GATEWAY
  &lt;/server&gt;
&lt;/match&gt;
</parameter>
</instance>   

Don't forget to correctly fill in your computer reference, Instance name, url etc.

Finally click Proceed to request the instance.

As the Fluentd configuration has many parameters for convenience we will write a short python script which will request the instance, instead of calling request function from Slapos Client.  

Create a python script and name it request_fluentd.py and copy/paste the presented code. 

** Don't forget to correctly fill in your computer reference, Instance name, url etc. 

As we are requesting instance of fluentd for the same computer the reference is the same as when we were supplying the software.

"YOUR_INSTANCE_NAME" -  give your instance a distinguishing name so you can later easily find it. For example Sensor-Tutorial-Fluentd.

Once it's ready run it by calling following command : 

This step can take some time.  

In your Slapos dashboard you can see you newly requested instance.

Instance is ready when the the Monitoring Status is green.

Note the Parameters section - there are the flunetd configuration parameters we defined earlier.

Login to your  Sensor and run the following command : 

sudo slapos node status

You see that a new service for Fluentd is added.

And the generated flunted configuration file is located here :

/srv/slapgrid/slappartX/etc/fluentd-agent.conf

Now your sensor is ready to retrieve data and to send it to, in our case, the IOT Gateway.