Havoc Pennington wrote, > Right, for a sufficiently low number of machines, setting up an > elaborate framework is going to be more annoying than just managing > them all separately. Though we should try to make the framework easy > enough to use that it makes sense even for a single machine, if we > can. Do you have any feel for how low that number is given the current stage of development? > I think there are maybe a couple answers to your question. > > 1) Should there be some kind of OS 'layering' (words like 'profile' > or 'inheritance' come to mind). <snip/> > But the idea is that any system on the network can run any workload > (workload = service, or even have desktop users log in). You then > keep a central mapping that assigns workloads to specific machines, > but you can change that mapping as required. > > This seems like the ideal, while in one sense "profiles" feels like a > workaround. I'm not so sure about this. There are many scenarios where it makes sense to restrict particular roles to a specific set of hosts, or to restrict particular hosts to a specific set of roles. Security is one (eg., to take an extreme example, I don't want a firewall to be able to run any workload) but it's not the only one. > 2) How can you avoid a separate 'profile' to make small changes. > This is a matter of pulling state out of the OS install and config > files. We've been approaching this by saying there's a toolbox you > can use. Here are some of the approaches in the toolbox: > > - dynamic/automatic configuration > - look up configuration from a central place, e.g. a directory > server, or even a file share > - write scripts that examine the machine and determine its desired > configuration based on hardware, network location, or by looking > up configuration from a central place > - move the configuration to be per-user rather than per-computer > > So some of this can be done out of the box in the OS; for example for > desktops, NetworkManager helps address network configuration that > varies between machines. A good kudzu helps avoid hardware config in > general. etc. But you'd expect a local site to do some work as well. As you say, a lot of this works already ... I work with parallel applications on clusters, and common configuration in a shared filesystem with symmetry-breaking via hostname works fabulously well given how trivial it is to set up (until the NFS server goes down, that is ;-). But it's pretty much limited to machines which are always connected to the same network. Extending this to laptops which move between networks, or no network at all could be a lot more challenging. OTOH, a scheme which could handle that case as well would be a huge bonus. > Anyway, to the extent that machines can vary by workload rather than > by install profile, so there can be a single install profile, that > seems desirable. > > I'm kind of sleepy so sorry if this answer is sort of muddled; but I > think your questions really get to the heart of what we're trying to > solve here. No, I think that it was clear and to the point. And I think it's an excellent problem to be trying to solve. Cheers, Miles
