@tom
I've tried docker run -v /sdcard:/sdcard, but not working. It's not showing sdcard directory.

As I'm working on this issue, I noticed the following.

yocto:/# ifconfig
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:65536 Metric:1
RX packets:32 errors:0 dropped:0 overruns:0 frame:0
TX packets:32 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:2224 (2.1 KiB) TX bytes:2224 (2.1 KiB)

wlan0 Link encap:Ethernet HWaddr :::::
inet addr:192.168..** Bcast:192.168..*** Mask:...
inet6 addr: :::::**/** Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:467 errors:0 dropped:0 overruns:0 frame:0
TX packets:88 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:3000
RX bytes:40293 (39.3 KiB) TX bytes:10317 (10.0 KiB)

https://stackoverflow.com/questions/64028448/error-during-connect-get-http-2fvar2frun2fdocker-sock-v1-40-containers-jso

It's not showing any IP address for docker0.
How to configure the IP address that will listen to docker daemon on voxl-core board?

yocto:/# systemctl status docker
● docker.service - Docker Application Container Engine
Loaded: loaded (/lib/systemd/system/docker.service; disabled; vendor preset: enabled)
Active: failed (Result: exit-code) since Mon 2021-01-11 06:31:53 UTC; 1min 53s ago
Docs: http://docs.docker.com
Main PID: 4675 (code=exited, status=2)

Jan 11 06:31:53 apq8096 systemd[1]: Started Docker Application Container Engine.
Jan 11 06:31:53 apq8096 docker[4675]: flag provided but not defined: --raw-logs
Jan 11 06:31:53 apq8096 docker[4675]: See '/usr/bin/docker daemon --help'.
Jan 11 06:31:53 apq8096 systemd[1]: docker.service: Main process exited, co...NT
Jan 11 06:31:53 apq8096 systemd[1]: docker.service: Unit entered failed state.
Jan 11 06:31:53 apq8096 systemd[1]: docker.service: Failed with result 'exi...'.
Jan 11 06:31:57 apq8096 systemd[1]: Stopped Docker Application Container Engine.
Jan 11 06:33:06 apq8096 systemd[1]: Stopped Docker Application Container Engine.
Hint: Some lines were ellipsized, use -l to show in full.

yocto:/# voxl-configure-docker-support.sh
Stopping original docker service
Enabling our own services docker-start & docker-prepare
starting docker-start.service
loading hello-world docker image
Cannot connect to the Docker daemon. Is the docker daemon running on this host?
yocto:/#

RE: https://forum.modalai.com/topic/37/docker-daemon-fails-to-start-voxl
I'm also facing the same issue.

yocto:/# voxl-docker -i roskinetic-xenial:opencv
Cannot connect to the Docker daemon. Is the docker daemon running on this host?
yocto:/#
yocto:/#
yocto:/# docker images
Cannot connect to the Docker daemon. Is the docker daemon running on this host?
yocto:/#
yocto:/#
yocto:/# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/root 2.8G 2.2G 581M 79% /
devtmpfs 1.8G 0 1.8G 0% /dev
tmpfs 1.9G 0 1.9G 0% /dev/shm
tmpfs 1.9G 17M 1.9G 1% /run
tmpfs 1.9G 0 1.9G 0% /sys/fs/cgroup
tmpfs 1.9G 4.0K 1.9G 1% /var/volatile
/dev/mmcblk0p1 7.4G 204M 7.2G 3% /mnt/sdcard
/dev/sda2 2.2M 80K 2.0M 4% /persist
/dev/sde12 12M 4.1M 7.4M 36% /dsp
/dev/sde11 95M 33M 63M 35% /firmware
/dev/sda3 58M 40K 57M 1% /cache
/dev/sda9 15G 13G 2.4G 85% /data
yocto:/#

As you can see, /data partition has all the data and docker images.

What can be a solution for this?

@Chad-Sweet
I'm using the Ubuntu Docker container on VOXL.
OpenCV4 in Python3 is working.

But I'm facing issues while mounting sdcard on it.
I'm referring to this link.

I'm using the below command to mount sdcard.
docker run -v /mnt/sdcard:/root/yoctohome/:rw -w /root/ roskinetic-xenial:opencv

How can I mount a sdcard on the Ubuntu Docker container on VOXL?

How can I use OpenCV4.x with Python3.6.9 using Ubuntu Docker container on VOXL?

@Chad-Sweet
If I'll use an Ubuntu Docker container on VOXL, can you provide documentation or steps using which I can build OpenCV4.x on Python 3.6.9?

Or a pre-build file of OpenCV4.x for Python3.6.9?

Thanks!

Yes, I have to run my program using Python3.6.9 and OpenCV 4.X.
And it wouldn't allow running a program on Docker container on VOXL.

I've installed Python3 on the voxl core-board. I've also installed OpenCV-3.4.6 using https://gitlab.com/voxl-public/other/voxl-opencv-3-4-6
But I'm unable to access OpenCV in Python3.
I'm getting an error like this.

/ # python3
Python 3.6.9 (default, Dec 19 2020, 12:09:26)
[GCC 4.9.3] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>>import cv2
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
ModuleNotFoundError: No module named 'cv2'

How to import OpenCV in Python3?

Any suggestions would be greatly appreciated!
Thanks!