I recently changed the hostname on my Raspberry Pi and was rather surprised (and initially worried) when the next time I started Node-RED all my flows has disappeared 😱
It turns out that the flows are connected to the computer hostname by their naming convention. Someone even filed a bug regarding this unexpected behavior.
The reason lies in the naming of the configuration files. If you take a look in the .node-red directory you’ll see something like this.
pi@thor:~ $ cd .node-red/ pi@thor:~/.node-red $ ls flows_raspberrypi_cred.json lib package.json settings.js flows_raspberrypi.json node_modules package-lock.json
Here’s you see two files that both contain the hostname (raspberrypi).
The fix is simple, just rename the files replacing the old hostname with the new hostname.
pi@thor:~ $ mv flows_raspberrypi_cred.json flows_thor_cred.json pi@thor:~ $ mv flows_raspberrypi.json flows_thor.json
Node-RED will need to be restarted to pick up the new configuration.
pi@thor:~ $ sudo systemctl restart nodered