AllAccepted answers
Robert Cemper · Apr 18, 2021

Your suggestion is valid:
IF - there is access with sufficient privileges to the server that hosts Docker.
This is most likely an OS Level system manager or operator that runs all containers.

BUT - To run / check  / restart ..  IRIS there is no need to have rights outside Docker container
but instead, you need direct access to OS inside the container. Without external rights.

The next level is SYSmgr access inside IRIS vs. Developer or User access.

Back to the original scenario:
Running Docker is to me from a security point of view the same as running  Linux/ Windows on an ESX.
Would you sugggest giving someone access to ESX  with enough privileges just to do
Windows System management?  I don't think so!
In any midsize to larger organization, there is a strict separation between
HW server, Network, Virtualization, OS, Application - Management & Operation
mainly to prevent mistakes and error fixing at the wrong end.

Of course for me at home with a notebook and 2 desktops, I'm godfather with all rights you can think of.

Docker is claimed to replace VMware.
This is only correct if after installation you have the same privileges. 
If I build my image, I have all access rights.
But with no access to root or similar, I feel cheated.
Sorry, it's like a car without a steering wheel.

Robert Cemper · Apr 18, 2021

Dear @Dmitry Maslennikov !
Thanks for the compliment "bad idea"  !
All my life was driven by cross thinking, away from old tracks, doing the undoable, unchain my mind.
And it was 99% success. 
My ISC colleagues in and outside US can confirm this.
@Evgeny Shvarov knows much more details about me that would break the frame here.

BUT I'm a little bit disappointed. You didn't read the disclaiming note on top:
It is for developers, supporters,  system managers. 
And in addition my examples are never meant for production use,
but for training and learning. I don't make money with my software.

Just 1  minor detail:
Though multiple requests I never got a root password for any IRIS container.
You might have access to this information as you have also access to other no-public info.
So I had to set one for myself.  x-thinking!

All about the reasoning and other details are in my reply to @Evgeny Shvarov
Since he placed the more important question: WHY?

Robert Cemper · Apr 14, 2021

If you get back large results sets that you use for further processing PyODBC will be better suited.
But for a small number of values, the overhead at both ends to service ODBC structures may not pay off
since both ends have to get their internal structure in to  ODBC and out of it.
I don't have measured the difference so this is just a guess:
- for the typical embedded SQL returning < 1..10 rows a MethodCall might be more efficient.
This doesn't prevent you from using and tuning an SQL SELECT isolated in IRIS environment. 
In any case, the transfer between PY and IRIS is the slowest piece.
The less data you transport the faster the action is completed.
And transport in blocks wins over isolated pieces in loops.