One-Machine Linux Cluster

An AC wrote: Forget Beowulf ^? clusters, Jacques Gelinas has made available a kernel patch to enable many virtual servers running on the same machine, even the same kernel. Read his original message posted to the Linux kernel list." Imagine what this will mean for hosting companies...

Comments

Basically Like OpenVMS' Galaxy?

[inhalent]

Basically the same idea as Galaxy. Check it out for ideas.... http://www.openvms.compaq.com/availability/galaxy. html

User Mode Linux?

[jmv]

Can anyone tell me how this is different than User Mode Linux?

Re:User Mode Linux?

[dispari]

User Mode Linux is basically a VM. It uses virtual devices for hardware multiplexing. Read the "Alternative technolgoies/Virtual Machines" and "Alternative technologies/Limitations of those technologies" for why this is a different (and better in some instances) solution.

The vunify tool has significance when differentiating between VM's and this.

Actually this is kind of an old idea

[Ghostx13]

Hostpro, now Interland has this sort of thing for freeBSD. It used to be called vserver. The new improved version is called Freedom. It's been out for years.

Re:Beaowulf not the target audience

[Xanni]

Like most Slashdot posters, you obviously didn't read the documentation before posting. On an 8-processor machine, this patch will give you 8 processors for each virtual server; it does /not/ implement CPU partitioning and explains the difference in the documentation.

Also the main server can see all the files in the virtual servers since it isn't chrooted.

It's not the processing power

[KMSelf]

It's the control over it.

Mainframes have insane amounts of control over user processes (a Linux image essentially becomes same), as well as the ability to allocate more resources, fewer, provide fine-grained process accounting, shut down processes, migrate them elsewhere (part of the IBM dataceter Linux concept is the ability to migrate nodes around the country as needed).

What a mainframe doesn't have to offfer is insane amounts of processor power or memory. Disk, and disk I/O are quite another matter -- the amount of aggregate bandwidth a z390 has to offer is impressive.

PC-based virtualization clearly has some advantages, through not all of those offered by a mainframe. A rack of virtualized PCs probably does offer a higher processor density than the equivalent mainframe, however.

Hardware isolation

[TBone]

Yes, the patch doesn't support hardware dedication. But my SUN background makes me ponder a line of thought.

In Solaris, there are the psr* family of commands for processor administration. psradmin -f 0 will turn off processor 0. As long as this isn't physical powering down of processors, and simply instructions to the scheduler to disregard p0, you could, on the above vm, do something like:

Prod: psradm -f 4,5,6,7
Test: psradm -f 0,1,2,3,6,7
Dev: psradm -f 0,1,2,3,4,5

Leaving procs 0-3 for Prod, 4-5 for Test, and 6-7 for Dev.

Along the same lines, at boot time you can explicitly state memory ranges to the kernel, if linux can't detect your memory right, or you have known bad memory you want to avoid. With the same thought, the Prod, Test, and Dev kernels can be brought up explicitly stating the 0-2G, 2-3G, and 3-4G ranges as usable memory addresses.

You run into more problems when it comes to peripherals in the box, but how many serial ports do you really need? Just specify ttyS0 in the VM with the addresses of ttyS0,1,2 of the physical server.

Am I smoking crack, or should I just stick with my much-more-hardware-flexible Sparc architecture :)