It is easy to get confused about the correct permissions but the rules are really quite simple.

Summary

For standard installations, do install Node-RED itself globally with admin rights (sudo, except on Windows where you use standard user rights unless really needing to install for all users) but do not install nodes globally.

When you run Node-RED, it should always be run without admin privalages. The exception is where you need to use a port less than 1024 as these normally require admin to run them (Node-RED defaults to port 1880).

If you make a mistake and install a node with admin rights, uninstall it and reinstall without. You may, however, need to check your userDir folder (normally ~/.node-red) to make sure that the access control privileges for all folder are correct.

Linux (and probably Mac)

See also the official documentation.

Dependencies

Unless you can use the official installation and upgrade script, you must ensure that all dependencies are installed. This includes Node.JS and npm. Simply follow the instructions on the Node.JS website for your distribution or operating system to get the latest “LTS” (Long Term Support) version of Node.JS that is supported by Node-RED (v6 or v8 at the time of writing). You should not rely on the version of Node.JS that comes with the default distribution libraries as this is typically long out of date.

Installation of Node-RED

There are two types of installation for Node-RED.

The standard installation

The standard installation is generally recommended. It is installed with admin privalages:

sudo npm install node-red -g

In this case, you can run Node-RED from anywhere with a command that is globally available:

node-red

The resulting process runs with the permissions of the logged in user, not with admin or root permissions.

Commonly though, you may well want to run Node-RED as a system process, a “daemon” in UNIX terminology. Generally, you should make sure that the resulting process does not start until after networking and any other dependent processes (such as databases) are active. You should also ensure that the process runs with the privalages of a specific, non-admin user.

To upgrade Node-RED, you should use the upgrade script provided if running under Debian/Ubuntu/Rasbian type versions of Linux. This ensures that all dependencies are met. Note that, as is typical with many Linux installations, any default versions of Node.JS and Node-RED available from core Linux distributions are likely to be out of date and should rarely be used. If you cannot use the upgrade script, simply run sudo npm upgrade node-red.

The “embedded” installation

The alternative to the standard installation is an embedded installation. You can use this either to embed in a large app or to allow multiple versions of Node-RED to run in parallel.

For embedded installations, you should not install Node-RED with admin privalages.

mkdir project-folder
cd project-folder
npm init -y
npm install node-red --save

The init and --save parts ensure that the folder contains a package.json file that will help you manage dependencies correctly.

Note that, you will need to manage the location of your userDir folder for this installation type. Typically, you will not want to use ~/.node-red but probably a sub-folder of the project-folder. See the Node-RED documentation for how to do this.

While this is harder to set up, it provides a much more flexible installation.

To upgrade Node-RED, you simply manage it like any other dependent Node.JS module.

cd project-folder
npm update node-red

Installation of nodes

Nodes are simple Node.js npm modules. They should always be installed with standard user permissions. The user in question needs to be the id that is running the Node-RED process.

By far the best way to install nodes is from within the Node-RED admin interface. Click on the “hamburger” menu and select “Manage pallette”. This will always install nodes to the correct folder (the userDir folder, typically ~/.node-red) where you can see the code in the node_modules folder (e.g. ~/.node-red/node_modules/).

Alternatively, you can install from the command line but must make sure you are in the correct location, the userDir folder as above. Don’t forget that, if you have used an embedded installation of Node-RED, the userDir folder will most likely be somewhere non-standard but you should still install nodes there even though installing them in the same folder as Node-RED itself will certainly work for most nodes (but that wouldn’t let you manage them from the Admin interface).

cd ~/.node-red
npm install node-red-contrib-uibuilder --save

Node permission issues

If you hit any privalage problems when running Node-RED, they typically come from either an incorrectly installed node (e.g. installed with sudo) or the node needs to access hardware that has limited access. The hardware issue generally only shows up on Linux.

To resolve such issues, all you need to normally do is to add the user to the appropriate group that has access to the hardware.

To check the group required, you will need to list the “file” that represents the hardware

ls -la /dev

You will likely see that the ports for serial and USB (which also includes Bluetooth) have group ownership set to group dialout. So you can add the user to the dialout group to get permission to the port.

sudo usermod -a -G dialout <username>

i2c permissions

i2c is a standard for 1-wire GPIO communications. It provides an efficient way to multiplex sensors to simple microprocessors. Such sensors are commonly used with the Pi. Unlike the serial and USB ports, i2c ports belong to a different group.

This will list all of the i2c recognised devices on your Pi:

ls -la /dev/i2c*

You should find that all of the devices belong to the group i2c. So you should add the user that runs Node-RED to that group with:

sudo usermod -a -G i2c <username>
Additional information on using i2c on the Pi

Windows

See also the official documentation.

Dependencies

Many Node.JS modules including some nodes for Node-RED require a compile stage. While most Linux platforms will have the tools to do this already installed, typically Windows does not. The easiest way to fix this is to install the build tools with npm install windows-build-tools -g. Again, you don’t have to do that from an admin console unless you want them available to all users on the PC. Even that may not always be enough so check out this article for more details if you still have build issues.

Installation of Node-RED

For modern versions of Windows, you should generally not use admin privileges to install Node-RED even when installing globally unless you really need to install it for all users. However, when you don’t, you do not actually get a global installation in the same way as Linux. Instead it is installed to %APPDATA%\npm (or $env:APPDATA\npm for PowerShell users) for the installing user. This is more secure, you can give permissions to other users if you need to.

To upgrade, use npm upgrade node-red -g as with other globally installed Node.JS modules.

You can, of course, also install in embedded style in the same way as for Linux.

Installation of nodes

With a standard installation,