Re: Windows Subsystem for Linux [WAS: new LilyDev, 0.2 release]

[Wols Lists]

On 01/01/18 14:49, Karlin High wrote:
> That place would probably offer more direct interaction with their
> developers. But I know too little about Linux internals to really take
> up an intelligent discussion there. CGroups? Namespaces? Never heard of
> these things before.

CGroups? Control Groups. Similar to a PID or Process Identifier.

If you're running service daemons, one of the problems with SysVInit was
it was possible (and fairly easy by mistake) to spawn a bunch of
processes that then wouldn't shut down properly. Linux can assign a
control group - which is inherited by spawned processes unless actively
over-ridden. PLEASE NOTE THIS HAS NOTHING TO DO WITH SYSTEMD. However,
systemd takes advantage of this, assigning control groups to daemons. So
if something goes wrong, systemd or the admin can do "kill
control-group", and *know* that everything will be killed.

Namespaces? Well, the WWW is a namespace, which is used to avoid java
applets having colliding names. At its simplest, a namespace is just a
set of rules that allow me to assign random names to my things, while
knowing that they can NOT collide with someone else's random names
provided we both abide by the same rules. So if I want to call my java
applet "foobar", its full name would be "foobar.youngman.org.uk". Not to
be confused with "foobar.karlinhigh.gmail.com" (although, technically,
that is breaking the rules because that's your email not your domain).
The thing I notice most reading kernel stuff is all the security vulns
when namespaces get confused and the kernel wrongly thinks "root" ==
"root.vm".

(And yes, the WWW is a subset of the DNS namespace.)

Cheers,
Wol