Using Octoprint with one Raspberry Pi and two printers

I have two Tronxy X3A printers.  I have Octoprint on one, but not on the other.  I love Octoprint so much that I can't stand not having it.  So I decided to connect both printers to my Pi.

Detailed instructions are given on the web here.

Without further ado, here's what I did.

Identify the port for my current printer

1. ssh into my Raspberry pi, with the user name of pi (which was set up when I installed Octoprint).  

    ssh -lpi octopi.local  

2. List the ports for the connected usb devices

    ls /dev/ttyUSB*  

3. Plug in the second printer, then relist the ports for the connected usb devices. The new device is the one for the second printer.

    ls /dev/ttyUSB*  

4. Get the device info for both devices, and find the differences (I have /dev/ttyUSB0 and /dev/ttyUSB1. You might have different devices.)

   udevadm info -a -n /dev/ttyUSB0 > devInfoUSB0
   udevadm info -a -n /dev/ttyUSB1 > devInfoUSB1
   diff -u devInfoUSB0 devInfoUSB1  

   My difference is this:

   ATTRS{bInterfaceProtocol}=="02"
   ATTRS{bInterfaceProtocol}=="ff"  

   Where my old printer is 02, and my new printer is ff
5. Create a named symlink to the appropriate USB port that will last through a reboot by editing the /etc/udev/rules.d/99-usb.rules file

   cd /etc/udev/rules.d
   sudo vi 99-usb.rules  

   Enter the following two lines in the file (specific for my printers):

   SUBSYSTEM=="tty", ATTRS{bInterfaceProtocol}=="02", SYMLINK+="ttyCDSX3A"
   SUBSYSTEM=="tty", ATTRS{bInterfaceProtocol}=="ff", SYMLINK+="ttyCPSX3A"
   

   The symlinks are the names I choose to use for the printer ports.
6. Open up Octoprint, go to the settings menu, and add the new ports to the additional ports box.

Create a second copy of Octoprint

1. Copy the octoprint directory

   cp -R .octoprint .octoprint2 

2. Copy the octoprint configuration file

   sudo cp /etc/default/octoprint /etc/default/octoprint2

3. Edit the octoprint2 configuration file to change the port and add a basedir

   sudo vi /etc/default/octoprint2

Edit my haproxy.cfg flie

The