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run bash script in background with process name

Got a script for activating a python venv and running a server in the background, but right now I am trying to keep the pid when I start the process and then kill the process with pid after I am done. However, it is not all the time is gets killed.
My question is, can I run the process with a name, then killing it by using pkill name after? and how will that look
#!/bin/sh
ROOT_DIR=$(pwd)
activate(){
source $ROOT_DIR/.venv/bin/activate
python3 src/server.py -l & pid=$! # <== This is the process
python3 src/client.py localhost 8080
}
activate
sleep 10
kill "$pid"
printf "\n\nServer is done, terminating processes..."

You can run programs with a specific command name by using the bash buildin exec. Note that exec replaces the shell with the command so you have to run it in a subshell environment like:
( exec -a my_new_name my_old_command ) &
However, it probably won't help you much because this sets the command line name, which is apparently different from the command name. So executing the above snippet will show your process as "my_new_name" for example in top or htop, but pkill and killall are filtering by the command name and will thus not find a process called "my_new_name".
While it is interesting, how one can start a command with a different name than the executable, it is most likely not the cause of your problem. PIDs never change, so I assume that the problem lays somewhere different.
My best guess is that the server binds a socket to listen on a specific port. If the program is not shutdown gracefully but killed the port number remains occupied and is only freed by the kernel after some time during some kind of kernel garbage collect. If the program is restarted after a short period of time it finds the port already been occupied and prints a misleading message, that says it is already running. If that is indeed the cause of your problem I would strongly consider implementing a way to graceful shutdown the server. (may be already closing the socket in a destructor or something similar could help)

I think you should have to use systemd for this case:
https://github.com/torfsen/python-systemd-tutorial

Django server is still running after CONTROL-C

I start Django server with python manage.py runserver and then quit with CONTROL-C, but I can still access urls in ROOT_URLCONF, why?

Probably you left another process running somewhere else.
Here is how you can list all processes whose command contains manage.py:
ps ax | grep manage.py
Here is how you can kill them:
pkill -f manage.py

Without seeing your script, I would have to say that you have blocking calls, such as socket.recv() or os.system(executable) running at the time of the CTRL+C.
Your script is stuck after the CTRL+C because python executes the KeyboardInterrupt AFTER the the current command is completed, but before the next one. If there is a blocking function waiting for a response, such as an exit code, packet, or URL, until it times out, you're stuck unless you abort it with task manager or by closing the console.
In the case of threading, it kills all threads after it completes its current command. Again, if you have a blocking call, the thread will not exit until it receives its response.

just type exit(), that is what I did and it worked

How to keep run Python Program in Background on Raspberry Pi after terminate ssh

i need to keep run my Python Program in Background on my Raspberry Pi after i close the ssh connection, Because i need to save Phidget information on a SQL DB
I try to do this with nohup but it seems that the python Program isn't even executed.
Because when I look into the MySql DB , after doing below there nothing inserted.
I type in :
pi#raspi ~/MyProjekt $ sudo nohup python sensorReader.py &
[1] 8580
and when i try to look if this process exist whit :
ps -A| grep 8580
it returns nothing.
So do i something wrong ?
How can i run the python program after close SSH Conneciton

I would recommend running your python program in a cron reboot job.
To edit your root cronjobs use
sudo crontab -e
And add the line
#reboot sudo python full_path/MyProjekt/sensorReader.py
Then reboot your pi with:
sudo reboot
And then confirm that your process is running:
ps -aux | grep python

I don't think this is an ssh connection issue, from what you say the program seems to execute and exit. Does your .py execute in an infinite loop? Else you shouldn't expect it to stay alive.
Then, about keeping a process alive after the parent has terminated (the shell in your case), nohup is the answer, that means ignore HUP signals (those sent by a terminating parent process).
The '&' just means 'execute in background'.
The cron solution is good if your program is meant to do something periodically, but if it should stay alive waiting for some event (like listening to a socket), I would prefer to create an init scritp, so that the program is run as a demon at boot time and only in the desired runlevels.

Killing a program with except: pass

Is there any way to kill a program that ignores all exceptions? Stupid, I know. I was testing something (since I wasn't sure what error a failed, embedded pig script would throw), forgot to limit the loop to a single day, and now it's just continuously running even though I used
ps -ef
to find and directly kill it. I would just let it run to completion since it will definitely terminate, but it runs hadoop jobs, and is needlessly using up resources/popping up on the terminal in between other tasks randomly. I'd like to avoid shutting my desktop down since I'm running other tasks, but will if it'll kill it...
I got the pid from
ps -ef
and used
kill -9
to directly kill it. It no longer shows up when I run
ps -ef | grep
but when I leave my terminal sitting for a little bit (even a new window) these "ghost" hadoop jobs show up that correspond to where the killed task would be.

Normally your Python program would need registered listeners to handle any kill signal you send it. See here:
https://stackoverflow.com/a/1112350/276949
There is a special kill signal (SIGKILL, denoted by-9) which will kill your process no matter what.
kill -9 <pid>

How to run server script indefinitely

I would like to run an asynchronous program on a remote linux server indefinitely. This script doesn't output anything to the server itself(other than occasionally writing information to a mysql database). So far the only option I have been able to find is the nohup command:
nohup script_name &
From what I understand, nohup allows the command to run even after I log out of my SSH session while the '&' character lets the command run in the background. My question is simple: is this the best way to do what I would like? I am only trying to run a single script for long periods of time while occasionally stopping it to make updates.
Also, if nohup is indeed the best option, what is the proper way to terminate the script when I need to? There seems to be some disagreement over what is the best way to kill a nohup process.
Thanks

What you are basically asking is "How do I create a daemon process?" What you want to do is "daemonize", there are many examples of this floating around on the web. The process is basically that you fork(), the child creates a new session, the parent exits, the child duplicates and then closes open file handles to the controlling terminal (STDIN, STDOUT, STDERR).
There is a package available that will do all of this for you called python-daemon.
To perform graceful shutdowns, look at the signal library for creating a signal handler.
Also, searching the web for "python daemon" will bring up many reimplementations of the common C daemonizing process: http://code.activestate.com/recipes/66012/

If you can modify the script, then you can catch SIGHUP signals and avoid the need for nohup. In a bash script you would write:
trap " echo ignoring hup; " SIGHUP
You can employ the same technique to terminate the program: catch, say, a SIGUSR1 signal in a handler, set a flag and then gracefully exit from your main loop. This way you can send this signal of your choice to stop your program in a predictable way.

There are some situations when you want to execute/start some scripts on a remote machine/server (which will terminate automatically) and disconnect from the server.
eg: A script running on a box which when executed 1) takes a model and copies it to a custer (remote server) 2) creates a script for running a simulation with the wodel and push it to server 3) starts the script on the server and disconnect 4) The duty of the script thus started is to run the simulation in the server and once completed (will take days to complete) copy the results back to client.
I would use the following command:
ssh remoteserver 'nohup /path/to/script `</dev/null` >nohup.out 2>&1 &'
eg:
echo '#!/bin/bash
rm -rf statuslist
mkdir statuslist
chmod u+x ~/monitor/concat.sh
chmod u+x ~/monitor/script.sh
nohup ./monitor/concat.sh &
' > script.sh
chmod u+x script.sh
rsync -azvp script.sh remotehost:/tmp
ssh remoteshot '/tmp/script.sh `</dev/null` >nohup.out 2>&1 &'
Hope this helps ;-)

That is the simplest way to do it if you want to (or have to) avoid changing the script itself. If the script is always to be run like this, you can write a mini script containing the line you just typed and run that instead. (or use an alias, if appropriate)
To answer you second question:
$ nohup ./test &
[3] 11789
$ Sending output to nohup.out
$jobs
[1]- Running emacs *h &
[3]+ Running nohup ./test &
$ kill %3
$ jobs
[1]- Running emacs *h &
[3]+ Exit 143 nohup ./test
Ctrl+c works too, (sends a SIGINT) as does kill (sends a SIGTERM)