Grafana Dashboard for SD-WAN Gateway (VCG)

Enable Telegraf on VCG

You can find the official guide here Monitor Gateways using Telegraf

The following is how I enable Telegraf on my demo environment.

Step 1: Add the user telegraf to sudo group

This is because Telegraf needs to run /opt/vc/bin/dispcnt command in /etc/telegraf/vcg_metrics.sh. The command to add user telegraf to sudo is

sudo usermod -G sudo telegraf

Sample screen capture from my demo environment:

Figure 2 – Add user telegraf to sudo group

Step 2: Edit the /etc/telegraf/telegraf.conf

By default, telegraf.conf is not exporting any metric. To make Telegraf export the metric in Prometheus format, ucomment the three lines below “## Export metrics to prometheus”. The following screen capture shows the change being made in my demo environment:

Figure 3 – Uncomment three lines below “Export metrics to prometheus”

The timeout for each command to complete needs to configured as 10s. In later release, the timeout is already configured as 10s, if this is the case, no change is required. If the timeout is 5s, uncomment and change the timeout value to 10s. The following screen capture shows the change being made in my demo environment:

Figure 4 – Uncomment and change the timeout value to 10s

Step 3: Restart the Telegraf

After the configuration change in Telegraf, restart the Telegraf service to make the change effective. The command to restart the service is

sudo systemctl restart telegraf

To check status of the telegraf service:

sudo systemctl status telegraf

The following screen capture shows restart and checking the status of telegraf:

Figure 5 – restart and check telegraf status

Step 4: Adjust the iptables

By default, Telegraf is listening on port 9273, waiting for the Prometheus client to visit. The VCG iptables by default block every source IP to access port 9273. Thus, the iptables rule need to modify to allow Prometheus client to connect to port 9273. The command is:

sudo iptables -I INPUT -p tcp -m tcp --source <Prometheus Client IP> --dport 9273 -m comment --comment "prometheus" -j ACCEPT

In my demo environment, the Prometheus machine IP address is 192.168.252.26, the following screen capture shows the corresponding iptables command:

Figure 6 – adjust iptables rule to allow the Prometheus client to connect to Telegraf (port 9273)

*Reminder: The iptables rule will not persist after reboot. You can edit /etc/iptables/rules.v4 to include this new iptables rule to make the change survive after reboot (or use any other methods you can comfortable with)

Step 5: Verification of Telegraf

To verify if the Telegraf is working or not, at the Prometheus client, issue this curl command:

curl http://<VCG IP address>:9273/metrics

The example screen capture shows Prometheus client get metrics from a VCG with IP address 24.11.0.54:

Figure 7 – Output of the curl request and response to Telegraf (only the first few lines are show as the output is very long)

If everything is working, the curl will get response. And in the response there will are a list of metrics with prefix VCG_ like the above screen capture.

It is worth to mention the Telegraf log file is at /var/log/telegraf.conf. By looking into this log file, we notice the metrics are obtained every 60 seconds:

Figure 8 – Telegraf log file with Telegraf running on VCG

Grafana Dashboard for SD-WAN Gateway (VCG)

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