Re: [Userops] Why is it hard to move from one machine to another? An analysis.

[Dave Crossland]

On 9 April 2015 at 11:58, Bob Mottram <address@hidden> wrote:

The distros we use
> > should provide a package manager that allow us to do this kind of
> > dependency isolation with all packages, not just Ruby/Python/_javascript_
> > stuff, while at the same de-duplicating the files used in multiple
> > "bundles" throughout the system.  Then we'd only need one package
> > manager.
>
> That exists, it's called Docker :)

Maybe Docker and containers are the way to go, but  I have some concerns.
Installing initially from a Dockerfile, or equivalent, might be ok but there
is then the problem of keeping the container up to date with security
patches, application upgrades and wotnot.

I think this is bare-metal mindset. You don't update the container; you create a new one, and you throw throw the old one away after its no longer in use. 

 

If upgrades involve rebuilding
from a Dockerfile then with my current server configuration that could take
several hours

Then your current server configuration is too monolithic. Probably you are thinking with a vm mindset. 

What do you see as the differences between containers and VMs?

 

If the server is powerful enough then there could be two partitions in which
you have an active and currently building partition which then swap over.

I would say: the server has two containers, one built a while ago and one built more recently, which then swap over.

Containers are light.

 

Maybe some of the latest octacore SBCs might be able to handle that without
there being too much of a performance hit.

Here's a nickel ;)

 

Another problem is detecting when a rebuild should occur. Currently I don't
know of any mechanism which would initiate that, and something new would need
to be written to check upstream repos for changes.

https://docs.docker.com/docker-hub/builds/

--

Cheers
Dave