Subj : Re: lightweight virtualization To : All From : Pancho Date : Thu Sep 11 2025 06:34:43 On 9/6/25 22:53, Theo wrote: > Richard Kettlewell wrote: >> Jimmy Logan writes: >>> I'd like to create some kind of service container on rpi4b which I have, >>> which would allow me to just install something in a normal way (not >>> programming the whole installation process like dockerfiles), without >>> changing anything on the current OS. >> >> You don’t need any Dockerfiles to use Docker. So, perhaps Docker will >> meet your needs. > > Isn't the problem that Docker isn't persistent? Next time the container > is started it loses the state from the previous time - so any changes you > make, starting with installing any packages and then on, have to be done > again? > > You can address that two ways. One is to map volumes into the container so > that they will keep the data on the host filesystem and it'll be there again > when the container restarts. Or you can make your changes then snapshot the > container ('docker commit') and then launch the snapshot as a new container. > As Richard says, containers are persistent. The confusion might be that some people, or at least me, don't rely on this container persistence for standard application persistence. I like volumes, they make it clearer what needs to be backed up. The tear-down, reproducibility of a non-persistent container was one of the things that appealed to me about Docker. But this was what I regarded as good practice rather than enforced. My perspective is almost certainly skewed by having been a software developer and the unit test way of working. Plus a bitter history of supporting systems that were problematic due to undocumented system changes to the host OS. This view is ideal, I don't know about pragmatic real systems. --- MBSE BBS v1.1.2 (Linux-x86_64) * Origin: A noiseless patient Spider (3:633/280.2@fidonet) .