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  • Re: lightweight virtualization

    From Pancho@3:633/280.2 to All on Thu Sep 11 06:34:43 2025
    On 9/6/25 22:53, Theo wrote:
    Richard Kettlewell <invalid@invalid.invalid> wrote:
    Jimmy Logan <punk.book8853@fastmail.com> 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 donΓÇÖt 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)
  • From Lawrence =?iso-8859-13?q?D=FFOlivei@3:633/280.2 to All on Thu Sep 11 09:57:10 2025
    On Wed, 10 Sep 2025 21:34:43 +0100, Pancho wrote:

    As Richard says, containers are persistent.

    They can be, they need not be. It is entirely possible to mount an
    instance of tmpfs to hold any writable storage, which will disappear as
    soon as the container instance terminates.

    --- MBSE BBS v1.1.2 (Linux-x86_64)
    * Origin: A noiseless patient Spider (3:633/280.2@fidonet)