Using MPI with two RaspberryPi - raspberry-pi

I am trying to make a 'dual core' RaspberryPi for a project I am working on. I had followed this tutorial by Simon Cox. Unfortunately I could not get the two RasPi to talk to each other. (This was using Hydra as the process manager)
After looking more carefully at the MPICH installers guide, which can be found here, I tried to use the -phrase to pass the passphrase I had created. However I could not find it as part of the hydra commands. So I re-installed with smpd and after many compiling attempts. I configured with:
/configure -prefix=/home/pi/mpich-install --with-pm=smpd --with-pmi=smpd
I also had to install libbsl-dev to get the MD5 that smpd requires. I also exported the path that the commands mpiexec and mpicc are in. After setting the passphrase I copied the image to a second SD card and put it in a second RasPi. I then set up the passphrase using ssh-keygen.
I was able to run the cpi program on the master Pi and the slave Pi individually but when I tried to run multiple processes on both at the same time I got the error
Fatal error in MPI_Init: Other MPI error, error stack:
MPIR_Init``_thread(392).................:
MPID_Init(139)........................: channel initialization failed
MPIDI_CH3_Init(38)....................:
MPID_nem_init(196)....................:
MPIDI_CH3I_Seg_commit(366)............:
MPIU_SHMW_Hnd_deserialize(324)........:
MPIU_SHMW_Seg_open(863)...............:
MPIU_SHMW_Seg_create_attach_templ(637): open failed - No such file or directory
Can someone please suggest how I can either fix this problem or get the RaspberryPis to communicate using MPICH?
Thanks
E.Lee

If anyone else has this problem make sure your hosts don't have the same name!
You can change it by following this tutorial http://raspi.tv/2012/how-to-change-the-name-of-your-raspberry-pi-new-hostname

Related

Is there a library for MSR605X that works with Raspberry Pi?

I have been trying to locate a working library for the MSR605X magnetic card reader/writer. At time of writing, I have tried five separate libraries. Only two of these were explicitly for the 605X the other three were for the older 605. All the libraries I have tried either did nothing at all or errored before completing a command (can't figure out the errors either).
I am running Raspberry Pi OS 32 bit on a Raspberry Pi 3 B+ the MSR605X communicates via a USB connection.
So far the library that seems to be most complete is: https://pypi.org/project/msrx/
However, I can not get this library to read or write (either nothing happens or I get a Serial exception "cannot reconfig port).
Any help or links to documentation for this reader is welcome.
EDIT: Adding the commands ran with the above library
msrx -D /dev/input/event4 read
msrx -D /dev/input/jso0 read
The -D is to specify the device path (default is /dev/ttyUSB0 which doesn't exist on my system). I obtained the above two paths by searching for USB serial devices then matching the search result to the device ID which I obtained from lsusb.
Running these commands results in a serial exception (could not reconfig port) which I assume means that I have the wrong device path. I have also checked for any tty* device paths that are changed when I plug in the reader. I consistently get a permission denied error whenever trying to run the above commands with a tty* device path (I am root on this system).
msrx author here — MSR605 requires an external 9V power injected into its cable (via the barrel jack port), otherwise it won't power up properly.

Failed to load the provider SiloedPackageProvider.dll and metaDeployProvider.dll

Trying to simulate Raspberry Pi in windows 10 laptop with windows 10 IOT Core.
http://annabooks.com/Articles/Articles_IoT10Core/Windows-10-IoT-Core-VM-Version-1.2.pdf
I found this article very useful but has used pre-built image “For MinnowBoard Turbot/MAX”.
I get these errors and other errors too.
Failed to load the provider SiloedPackageProvider.dll and metaDeployProvider.dll
CFfuMiscHelpersT ValidateNotOnTheSameDisk#904 failed with 0x80070001.
while executing this command from winpe.
Dism.exe /Apply-Image /ImageFile:"d:\Flash.ffu" /ApplyDrive:.\PhysicalDrive0 /SkipPlatformCheck
Failed to load the provider SiloedPackageProvider.dll and metaDeployProvider.dll
Also please tell me a way to copy logs from the VM running though HyperV.
Thanks
This issue occurs when you try to back up a specific library or when you accept the default settings in Windows Backup and Restore.You may try to follow up this document to fix the issue.
There are various ways exist to copy data between a Hyper-V host and its guest machines. You can search the ways from internet, or open a new issue for help.

vtctlclient: command not found

I am trying to run Vitess on Minikube and I'm going through the 'Getting Started' steps found here: http://vitess.io/getting-started/#set-up-google-compute-engine-container-engine-and-cloud-tools
I have installed everything I need to including 'vtctlclient'. I have verified that all the correct directories were created when I did this.
However, there is a script in my directory '/go/src/github.com/youtube/vitess/examples/kubernetes' called 'kvtctl.sh' which uses kubectl to discover the pod name and set up the tunnel and then runs 'vtctlclient'. When I run this script, this is what is returned:
'Starting port forwarding to vtctld...
./kvtctl.sh: line 29: vtctlclient: command not found'
I am totally lost as to why the vtctlclient command is not found because I just installed it using Go.
Any help on this matter would be much appreciated.
Maybe the go install directory is not in your path. Have you tried running vtctlclient manually (just like kvtctl.sh does)?
PS: You may want to join our Vitess Slack channel where you may get more prompt answers for your questions. Let me know if you need an invite.

RPi2 UART Setup & Operation Issues

I'm currently busy with my masters project which involves setting up comms on UART between a Raspberry Pi Model 2 B V1.1 and a Pixhawk Flight Controller using Mavlink protocol.
The first step is, of course, to get the UART set up and working. I'm not one to run after help at the first sign of a problem. I have been struggling with this for days and it's forced me to doubt the purpose of my existence more than once. I feel stupid and frustrated. Please see if you can provide any assistance.
My first resource was this tutorial, which should be relatively straight forward:
http://ardupilot.org/dev/docs/raspberry-pi-via-mavlink.html
The tutorial simply installs all the necessary packages and dependencies, as well as sets up the UART. I followed the steps to disable OS use of the serial port through raspi-config, however after attempting to test the connection I get an error:
[Errno 2] No such file or directory: '/dev/ttyAMA0'
Which is very strange. So after disabling and enabling OS use of serial port through rasp-config a few times and checking, every time I disable it, the /dev/ttyAMA0 file disappears. Now how the hell is anything supposed to work on the UART if disabling OS use of the UART removes that file!? Nevertheless I powered through. I enabled OS use of the serial port, which leaves the ttyAMA0 file right where it is and followed another suggestion, which is to change the /boot/cmdline.txt and remove all reference to ttyAMA0, as shown in the following link:
http://www.raspberry-projects.com/pi/pi-operating-systems/raspbian/io-pins-raspbian/uart-pins
This seemed to work alright. I could now initiate comms between the RPi and the Pixhawk flight controller and get some information that looked correct. Then the black magic started. The next day I tested the connection and it consistently spat out complete rubbish. But Nothing changed since the previous day. Somewhere I must be missing something. I followed all the same tutorials and steps attempting to get the more positive results I got the previous day. However that only led to more erratic behaviour. When connecting the serial lines to my Pixhawk Flight Controller, the keyboard/mouse seems to get interrupted momentarily every now and then. Everything just went backwards. I have already reinstalled Raspbian Jessie in a desperate attempt to get things to work.
Here are a few things I suspect could possibly contribute to the problems:
Baud rate not correct (to communicate with my Flight Controller baud rate needs to be 57600). Best way I've found to set this baud rate is to append "init_uart_baud=57600" to /boot/config.txt/. I have also read about other ways such as appending a line to /etc/crontab. Any suggestions?
Pixhawk miraculously and sporadically refused to communicate back with RPi.
Any assistance will be appreciated. Thank you.
SOLVED:
Looks like a known bug in the latest raspbian, easy to fix though.
These need to be done as the root user.
Disable "serial console" through GUI-preferences or "sudo raspi-config." Then reboot the pi.
Then change the following line in the file /boot/config.txt at the bottom of the file from:
enable_uart=0
to
enable_uart=1
Disable the ModemMonitor service by running the following command as root:
systemctl disable ModemManager.service
Then add youself to the dialout group, just to be sure you have the required permissions on the serial port:
adduser pi dialout
That should give you unrestricted proper access to the serial port.
Resources:
[url]https://www.raspberrypi.org/forums/viewtopic.php?f=66&t=148515[/url]
and
[url]https://www.raspberrypi.org/forums/viewtopic.php?f=28&t=82779[/url]
I had researched this for days now and troubleshooting all the readings listed on Google sites. I solved the serial UART settings for connecting my RPi3 Model B (typed at command line the following:
`cat /proc/cpuinfo`
to find my Pixhawk hardware info.)
FYI: You must be root when working with mavproxy so, sudo su
or sudo -s
Also, you must be a member of the dialout group, so do this at CMD line:
sudo usermod -a -G dialout root (enable root user!)
Do all the RPi regular stuff:
sudo apt-get update && sudo apt-get upgrade and sudo rpi-update.
Did all as outlined in the Ardupilot website. I did NOT use the
"apsync-rpi". (I used the 2017-03-02-raspbian-jessie.img.) at here
On my RPi3, using $uname -a: results--> Linux raspberrypi 4.4.50-v7+
My $sudo nano /boot/config.txt file has one change at bottom of file;
THIS statement: enable_uart=1 (has a good side effect of forcing the
core_freq to 250 which reduces poor signal frequency)
Important discovery: so the articles state that RPI3 UART and tty settings have changes. (link here)
What I have discovered after much ado is this for my sudo nano /boot/cmdline.txt file:
dwc_otg.lpm_enable=0 console=tty1 root=/dev/mmcblk0p2 rootfstype=ext4 etc.,.
-Notice I am not using ttyS0 in the /boot/cmdline.txt file. I tried the ttyS0 a dozen times and it never worked properly. For some reason, I am not able to explain it at this time, although the console=/dev/tty1 works if written in the /boot/cmdline.txt file.
Make sure you have the wiring correct between your RPi and the Pixhawk.
Telem 2. Also set the correct parameters in Mission Planner as I
have;
Go to CONFIGTUNING->STANDARD PARAMS; (my settings)
-The Serial0 baud rate(SERIALO_PROTOCOL) is: 115200
-The Console protocol selection(SERIAL0_PROTOCOL) is: MAVlink1
-Telem1 baud rate(SERIAL1_BAUD) is at: 115200
-Telem1 protocol selection(SERIAL1_PROTOCOL) IS MAVlink2
-Telemtry 2 Baud rate(SERIAL2_BAUD) is 921600
-Telemetry 2 protocol selection(SERIAL2_PROTOCOL) is MAVlink1
The RPi and pixhawk communicate at 921600 baud rate.
-Once I get the RPi3 powered up with it's own +5/VCC source and connect to my MP with a 3.0 USB cable from my PC-Windows10PRo, (okay, I have Arch and Debian Linux distros and Apple OSes too!) I enter:
`mavproxy.py --master=/dev/ttyS0 --baudrate 921600 --aircraft Plane`
It works for me!
Happy experimenting and flying!

could not open session as Root

I came across this error that is apparently pretty common among Linux Systems.
"Too many files Open"
In my code I tried to set the Python open file limit to unlimited and it threw an error saying that I could not exceed the system limit.
import resource
try:
resource.setrlimit(resource.RLIMIT_NOFILE, (500,-1))
except Exception as err:
print err
pass
So...I Googled around a bit and followed this tutorial.
However, I set everything to 9999999 which I thought would be as close to unlimited as I could get. Now I cannot open a session as root on that machine. I can't login as root at all and am pretty much stuck. What can I do to get this machine working again? I need to be able to login as root! I am running Centos 6 and it's as up to date as possible.
Did you try turning it off and on?
If this doesn't help you can supply init=/bin/bash as kernel boot parameter to enter a root shell. Or boot from a live cd and revert your changes.
After performing an 'strace su -', I looked for the 'No such file or directory' error. When comparing the output, I found that some of those errors are ok, however, there were other files missing on my problem system that existed on a comparison system. Ultimately, it led me to a faulty line in /etc/pam.d/system-auth-ac referencing an invalid shared object.
So, my recommendation is to go through your /etc/pam.d config files and validate the existence of the shared object libraries, or, look in /var/log/secure and it should give some clue to missing shared objects as well.