WelcomeWelcome | FAQFAQ | DownloadsDownloads | WikiWiki

Author Topic: Overlapping mounts  (Read 1734 times)

Offline CentralWare

  • Administrator
  • Hero Member
  • *****
  • Posts: 1652
Overlapping mounts
« on: October 21, 2014, 11:33:59 PM »
I've been experimenting with different means to accomplish a task I need but so far I've found many more issues at each turn, so I've come up with a theory which might work but I am not entirely sure how to implement it.

Core: 4.7.7
Kernel: 3.0.21
Remastered to include hardware support (ie: acpid) and file systems (dos/e2/ntfs)

What I would like to do (and am curious about) is similar to boot codes of tce=, home=, etc. and SquashFS but more complicated as it overlaps the ROOT.

Let's say I have a share (nfs/cifs) at server:/nfs/MachineID
What I would LIKE to do is a root overlap where all files/directories contained on the share are merged with the root ( / ) similar to a squash mount as if the following were possible:

Code: [Select]
mount -t nfs --bind server:/nfs/MachineID /* it's assumed the share is r/o as it's purpose is more of a roaming software profile as opposed to saving changes.
* in this fashion, if I were to update a given machine with a new app (say ethtool for example) it's just a matter of un-squashing the TCZ onto the share with any associated dependencies and viola'...  it's not a "part" of the given machine the next time it boots or if the machine is instructed to refresh itself.

Does anyone have $0.02 to share on this by chance as it would be greatly appreciated!


Please disregard question.
After ripping apart tce-load I noticed it's just doing a mount (/tmp/tcloop) and then copying contents from the mount to the root.  I was hoping there to be some kind of "loop" option to mount an active FS to the root without doing a recursive copy.
« Last Edit: October 22, 2014, 01:42:29 AM by centralware »
Over 90% of all computer problems can be traced back to the interface between the keyboard and the chair

Offline curaga

  • Administrator
  • Hero Member
  • *****
  • Posts: 10957
Re: Overlapping mounts
« Reply #1 on: October 22, 2014, 02:12:02 AM »
The merging functionality is a part of unionfs/aufs/union mounts, which we've never supported, as their reliability is worse than symlinks or copying.

Instead of root, you might only mount /usr over NFS? Home, /etc, /opt, /tmp, and other such directories need to be writable at runtime. You might need to run each startup script manually on the client in this case.
« Last Edit: October 22, 2014, 02:13:40 AM by curaga »
The only barriers that can stop you are the ones you create yourself.

Offline CentralWare

  • Administrator
  • Hero Member
  • *****
  • Posts: 1652
Re: Overlapping mounts
« Reply #2 on: October 23, 2014, 02:52:06 AM »
@curaga: Thank you for your input.  UnionFS...  isn't that from "way back"?
(curiosity got me...  did a quick wiki...  1980's via Sun Micro. though I don't think the name "union" was until a decade later.)

I'll come up with something!  Thanks again!

EDIT: Curious... I scanned through the scripts for the Java installer (4.x) and noticed it was well outdated.  I repeated for 5.x...  same source and likely invalid considering Sun has JRE 8u25 listed as recent and I doubt 7x is available anymore since the script tells you to download it manually.  Since it seems nobody keeps up with these "installer scripts" I've had to implement replacements and in doing so, they're actually nabbing current version info from the internet as opposed to a static version.  In my eyes, they're "anybody can do it" projects...  well, anyone with a little scripting experience at least, but since nobody SEEMS to be doing so, do you guys want me to ship them in once "perfected?"  (This one's intended for Firefox, Flash, Java and a few others so I figured I'd build a system that uses only the "most recent stable" and if added to cron, startup, etc. they could "check" for revisions when ever desired.)
When complete, it's going to be saved as a TCZ anyhow, thus I figured I'd ask since I can imagine there's quite a few peeps out there wishing for "newer" as is the case here.  IF SO, send me a link to the docs regarding taking over old projects if you would.  Thanks!
« Last Edit: October 23, 2014, 03:00:33 AM by centralware »
Over 90% of all computer problems can be traced back to the interface between the keyboard and the chair