Category: Technology

I want to move my energy measurement data to another InfluxDB database on the same server to create a new downsampling policy.

select * into Verhaeg_Energy..[measurement_name_destination] from Verhaeg_IoT..[measurement_name_source] group by *

Be aware of the .. in between the database name and the measurement name.

The InfluxDB start-up script checks if the HTTP service is running by trying to connect to it. However, I have disabled HTTP in my configuration and use HTTPS. This behavior is also described on Github.

You can workaround this issue by adjusting the InfluxDB service configuration file (/etc/systemd/system/influxd.service). The commented out lines are old configuration and replaced by the used lines.

[Unit]
Description=InfluxDB is an open-source, distributed, time series database
Documentation=https://docs.influxdata.com/influxdb/
After=network-online.target

[Service]
User=influxdb
Group=influxdb
LimitNOFILE=65536
EnvironmentFile=-/etc/default/influxdb
ExecStart=/usr/bin/influxd -config /etc/influxdb/influxdb.conf $INFLUXD_OPTS
#ExecStart=/usr/lib/influxdb/scripts/influxd-systemd-start.sh
KillMode=control-group
Restart=on-failure
Type=simple
#Type=forking
PIDFile=
#PIDFile=/var/lib/influxdb/influxd.pid

[Install]
WantedBy=multi-user.target
Alias=influxd.service

This article describes how to configure TLS for Mosquitto using a self-signed certificate. I assume that Mosquitto is installed and running.

Browse to the right directory:

cd /etc/mosquitto/certs 

Generate a 3DES private key using OpenSSL and put it in the moquitto directory for certificates:

openssl genrsa -des3 -out ca.key 2048

Generate the 3DES certificates using the private key:

openssl req -new -x509 -days 3650 -key ca.key -out ca.crt

Copy the certificate to the right directory:

sudo cp ca.crt /etc/mosquitto/ca_certificates/

Generate an RSA private key :

openssl genrsa -out server.key 2048

Generate the RSA public key:

openssl req -new -out server.csr -key server.key

Generate the RSA certificates using the private key:

openssl x509 -req -in server.csr -CA ca.crt -CAkey ca.key -CAcreateserial -out server.crt -days 3650

Configure Mosquitto to listen for TLS connections:

cd /etc/mosquitto/conf.d
nano listener.conf

listener xxxx 192.168.x.x
cafile /etc/mosquitto/ca_certificates/ca.crt
certfile /etc/mosquitto/certs/server.crt
keyfile /etc/mosquitto/certs/server.key
require_certificate false

I don’t enforce the usage of a certificate.

Go to the certificates folder and give the right permissions to the generated certificates.

cd /etc/mosquitto/certs
chmod 400 server.key
chmod 444 server.crt
chown mosquitto server*

Restart the Mosquitto service:

systemctl restart mosquitto.service

This is working for me now. However, while I was documenting this process I figured out I might have mixed up the 3DES and RSA certificates in the Mosquitto configuration. Something to look into at a later moment in time.

I’m using Proxmox as a hypervisor to run my virtual machines and use two VLANs in my home network: one for normal traffic and one separate VLAN for IoT traffic. Virtual machines should be connected to one of those networks. The normal network is typically untagged (vlan ID 20) while the IoT traffic is tagged with VLAN 21.

Configuration file: /etc/network/interfaces

auto lo
iface lo inet loopback

iface eno1 inet manual

auto vmbr0
iface vmbr0 inet manual
        bridge-ports eno1
        bridge-stp off
        bridge-fd 0
        bridge-vlan-aware yes
        bridge-vids 2-4094

auto vmbr0.20
iface vmbr0.20 inet static
        address 192.168.20.x/24
        gateway 192.168.20.1

This should result in the following Proxmox network configuration:

Now you can easily add a network adapter to a virtual machine and tag it with the correct VLAN.

sudo apt-get remove --purge x11-common
sudo apt-get autoremove
sudo apt-get update --allow-releaseinfo-chang