Excerpts from Lars Kellogg-Stedman's message of 2014-10-14 12:50:48 -0700: > On Tue, Oct 14, 2014 at 03:25:56PM -0400, Jay Pipes wrote: > > I think the above strategy is spot on. Unfortunately, that's not how the > > Docker ecosystem works. > > I'm not sure I agree here, but again nobody is forcing you to use this > tool. > > > operating system that the image is built for. I see you didn't respond to my > > point that in your openstack-containers environment, you end up with Debian > > *and* Fedora images, since you use the "official" MySQL dockerhub image. And > > therefore you will end up needing to know sysadmin specifics (such as how > > network interfaces are set up) on multiple operating system distributions. > > I missed that part, but ideally you don't *care* about the > distribution in use. All you care about is the application. Your > container environment (docker itself, or maybe a higher level > abstraction) sets up networking for you, and away you go. > > If you have to perform system administration tasks inside your > containers, my general feeling is that something is wrong. >
Speaking as a curmudgeon ops guy from "back in the day".. the reason I choose the OS I do is precisely because it helps me _when something is wrong_. And the best way an OS can help me is to provide excellent debugging tools, and otherwise move out of the way. When something _is_ wrong and I want to attach GDB to mysqld in said container, I could build a new container with debugging tools installed, but that may lose the very system state that I'm debugging. So I need to run things inside the container like apt-get or yum to install GDB.. and at some point you start to realize that having a whole OS is actually a good thing even if it means needing to think about a few more things up front, such as "which OS will I use?" and "what tools do I need installed in my containers?" What I mean to say is, just grabbing off the shelf has unstated consequences. > > Sure, Docker isn't any more limiting than using a VM or bare hardware, but > > if you use the "official" Docker images, it is more limiting, no? > > No more so than grabbing a virtual appliance rather than building a > system yourself. > > In other words: sure, it's less flexible, but possibly it's faster to > get started, which is especially useful if your primary goal is not > "be a database administrator" but is actually "write an application > that uses a database backend". > > I think there are uses cases for both "official" and customized > images. > In the case of Kolla, we're deploying OpenStack, not just some new application that uses a database backend. I think the bar is a bit higher for operations than end-user applications, since it sits below the abstractions, much closer to the metal. _______________________________________________ OpenStack-dev mailing list OpenStack-dev@lists.openstack.org http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev