Open Source Tech

Use InfluxDB 2 as a Metric Server for Proxmox


InfluxDB will run on in a Docker container.

This setup assumes that a Docker host is accessible on the LAN. In this example, the local domain is vnet and the host name is docker4.

Therefore, the Docker host FQDN is docker4.vnet

InfluxDB Container

Your USERNAME, PASSWORD, and ORG will vary.

I made my org the same as my local networking domain, but that is not a requirement.

docker run -d \
     -p 8086:8086 \
     --mount type=volume,source=influx-data,target=/var/lib/influxdb2 \
     --mount type=volume,source=influx-conf,target=/etc/influxdb2 \
     --name idb \
     -e DOCKER_INFLUXDB_INIT_PASSWORD=secret-password \

Connect Proxmox to InfluxDB 2

As of Proxmox 6.4, it is possible to use the version 2 API of Influx.

Before that, Proxmox would connect to Influx 1.x, but it was sending graphite line protocol over UDP (yuck). Now it connects via TCP/HTTP to the Influx API.

Get the Token

Log into the Influx web user interface, and copy the token for the user.

Click the token name to reveal the token.


There is probably a command-line way to do that, but I don’t know it.

Configure Proxmox Metric Server

The name can be whatever you want.

Paste the token from the last step into the “Token” field in the Proxmox UI.

Confirm Proxmox is Saving to InfluxDB

Navigate back to the InfluxDB web UI, and confirm that data is flowing. http://docker4.vnet:8086/

If things are working, there will be some measurements that clearly look related to Proxmox resource utilization.

Next Steps

In the next post, we will connect the InfluxDB bucket to a pre-built dashboard using Grafana.


No man ever steps in the same river twice, for it’s not the same river and he’s not the same man.

This is a quote by Heraclitus. He lived from 535-475 BC.


“We have two ears and one mouth so that we can listen twice as much as we speak”

This is a quote by Epictetus. He lived from 55-135 AD.

Listening goes beyond verbal communication. Listening to your own body, to your muscles, and making the mind-body connection is one example of listening. Another example is hearing the sounds of nature. Another is watching how people react to what you say.

Listen with two ears in every sense of the word that you can imagine.

Open Source Tech

Disable Multipath for Identical NVMe Drives on Ubuntu Server

I have 4 identical NVMe drives installed in my system.

Ubuntu treats them as one “multipath” device by default. This is not accurate.

I posted something on Ubuntu Forums, but no response at time of writing. (2021-02-18)

Here’s the problem:

 nvme0n1                   259:0    0   1.9T  0 disk  
 └─mpatha                  253:1    0   1.9T  0 mpath 
 nvme1n1                   259:1    0   1.9T  0 disk  
 └─mpatha                  253:1    0   1.9T  0 mpath 
 nvme2n1                   259:2    0   1.9T  0 disk  
 └─mpatha                  253:1    0   1.9T  0 mpath 
 nvme3n1                   259:3    0   1.9T  0 disk  
 └─mpatha                  253:1    0   1.9T  0 mpath 

The fix is relatively simple. It is outlined in some SUSE Documentation.


blacklist {
       devnode "^nvme[0-9]"

Once the config file has been changed, apply the changes according to the Ubuntu Server Documentation.

sudo systemctl restart multipathd

And all is good!

 nvme0n1                   259:0    0   1.9T  0 disk 
 nvme1n1                   259:1    0   1.9T  0 disk 
 nvme2n1                   259:2    0   1.9T  0 disk 
 nvme3n1                   259:3    0   1.9T  0 disk 

Beef Shoulder Roast

Beef shoulder roast and beef chuck roast were on sale at Harris Teeter.

The sticker on the shoulder roast package said “oven roast” and the one on the chuck roast package said “pot roast”.

I put the shoulder roast in the oven. It worked out well.

It tastes like the beef that comes in a Chinese restaurant dish. It is relatively tough and relatively lean. Has good strong flavor. Would definitely make again.

It was delicious cut up into strips to make a sandwich!



I tried making hamburgers today. The result tasted like bland meatloaf.

I’ll try again later this week.


How Bloated is Windows 10?

Despite the click-bait header, I will not comment on whether the size of a Windows installation is “too” big.

However, I do have facts!

I installed Windows 10 version 20H2 on a VM with no internet connection.

Once I was on the home/welcome/desktop screen, the installation used 18.8 GiB.

After performing Windows updates, and installing VirtIO drivers (to help performance of VM) the total install size was 23.5 GiB.

These results were logged on 2021-02-07.

Open Source Tech

Fail: USB Passthrough to Dexcom 6 Reciver

My T1 Diabetic Connundrum

I want to connect my Dexcom receiver to a computer. This will allow me to track my blood glucose over time. Then, I can identify trends and patters to help improve my insulin dosing.

Mac and Linux

Dexcom’s software only appears to work for Windows. I only have Mac/Linux/FreeBSD machines at home. I want to pass the USB Dexcom device through to a Windows VM.

Proxmox USB Passthrough: Success

For many people and use cases, this seems to work fine!

I was able to pass a USB flash drive through to a Windows VM with no issue.

Proxmox USB Passthough: Fail

Things were looking promising after the USB flash drive worked!

They looked even more promising after the Qemu Monitor recognized the Dexcom device.

qm> info usbhost
   Bus 1, Addr 15, Port 10, Speed 12 Mb/s
     Class 02: USB device 22a3:0047, DexCom Gen4 USB Serial

Unfortunately, the device was not recognized by the Windows Device Manager.

I thought this might be fine, and that the Dexcom software would find the right driver and solve the problem! However, the Dexcom program gave prompts as if the device was not plugged in.


Proxmox has robust documentation on USB passthrough on their wiki.

The basic things I tried were

  • Physically unplug and re-plug the device
  • Drop/Add the Qemu USB device using USB bus/port numbers
  • Drop/Add the Qemu USB device using Vendor and Product IDs

Sample Commands:

#device info
 qm> info usbhost
   Bus 1, Addr 15, Port 10, Speed 12 Mb/s
     Class 02: USB device 22a3:0047, DexCom Gen4 USB Serial
#by bus and port
 device_add usb-host,hostbus=1,hostport=10,id=usb1
 device_del usb1

#by vendor and product ID
 device_add usb-host,vendorid=0x22a3,productid=0x0047,id=usb1
 device_del usb1

I tried in different USB ports, after restarting VM, and other miscellaneous troubleshooting as well.

The results were consistently the same failure.


I borrowed a Windows laptop, and it worked fine!

I’m not sure what the root cause is for this issue. One possibility is that the Vendor ID seems to be in USB device databases on the web, but the product ID is not.

It is possible that Proxmox needs to have a valid/known product ID to pass to the VM.

It is also possible that the Dexcom software is written in a way that just doesn’t work when the USB device is not on the bare-metal machine. After all, the VM does need a virtualized USB hub etc., so it might just inevitably break some code.

Another possibility is that the Windows OS layer isn’t pulling the device details through properly, even though Proxmox is sending all it can.

Who knows! With such a tall software stack, combined with a tiny user base (type 1 diabetics with this particular device who are tech nerds like me) the answer to this question is likely to remain a mystery forever. Oh well.

First Times Food

First Ever Rib Roast

I’ve never baked a beef rib roast before! Here’s the story of what happened.

Seasoned it with salt, pepper and garlic. Placed on countertop for a few hours. Put into the oven when the roast was 52 degrees.

Baked at 250 degrees for about 3 hours. Once the roast reached 120 degrees, cranked the oven up to high for almost 10 minutes to get a sear.

After searing and removing from the oven, the roast was at around 126 degrees.

The result was pretty good! I was going for medium rare, but ended up at a medium.

For my first-ever attempt: I’ll take it! 😀

Next time I’ll endeavor to have it closer to rare. Stay tuned.

Open Source Tech

Bulk Resize Images for WordPress

Here’s a python script.

import os
import subprocess

# inspired by this post

def main():
    # the maximum length in any direction (width or height)
    # setting at 1600 because full HD (1920x1080) seems larger than necessary
    # this will allow 1600x900 (or portrait 900x1600) images.
    MAX_LEN = "1600" 
    size_parm = MAX_LEN+'x'+MAX_LEN+'>' #
    # files in the input directory will (at least SHOULD) remain untouched.
    # files with identical names will be created in the output directory.
    # files in the output directory are OVERWRITTEN (if they already exist and the names match)
    IN_DIR = '/home/vince/Pictures/WordPress'
    OUT_DIR = '/home/vince/Pictures/WordPressSmall'

    # show what is about to happen
    print ('Input: ', IN_DIR)
    print ('Output:', OUT_DIR)
    print ('Resize Geometry:', size_parm)

    for filename in os.listdir(IN_DIR):
        # get full file paths
        infile =  os.path.join(IN_DIR, filename)
        outfile = os.path.join(OUT_DIR, filename)

        # this is not necessary because the ImageMagick library supports shrinking only
        # AND maintaining aspect ratio. all the logic is basically done.
        # the '>' in size_parm prevents making the image larger.
        # #get width and height
        # width = subprocess.check_output(['identify', '-format', '%w', filepath])
        # width = int(width.decode())

        # convert and print output
        subprocess.check_output(['convert', infile, '-verbose', '-resize', size_parm, outfile])

if __name__ == '__main__':