About-diskless-boot (Part 1) - concept and simple methods

Understanding Diskless installs

Concept of disk-less installs in Alpine Linux

• Diskless = RAM based installs = Running your OS from RAM
• Concept involves that post-boot there are no real persistent installs of files on disk. This means on next reboot packages(.apk) would be re-installed and re-configured.
• Concept has provisions(lbu) to save user-modified config files that usually resides in /etc folder. These files are over-layed over file system on post-reboot. Saved configs come in effect and are used by applications when called.

Techniques employed

• Standard/Official installs.
• True diskless.
• Disk-less variants.

How to work on it(exploit), or make best use of it

Do's

• Keep a check on /usr folder

du -csh /usr
 -> 810.2M /usr

• Keep a check on memory usage

free -m 
 -> 450M 

• Create/use SWAP disk if needed.

Don't

• Do not rush to update/upgrade.
• Always try to avoid edge in disk-less installs.
• Avoid upgrading stable setup to edge.

Is it possible to load the OS into ram at the ISO's boot prompt?

Not yet, but see AlpineLinux.True-diskless-boot.

Some diskless boot dramas'

1. Standard/Official diskless boot - ISO/Boot-disk + RAM ^{[5] [6]}
2. True-diskless-boot - closer to RAM
3. Diskless-install-on-devices-with-2gb-ram - closer to Disk
4. Diskless-install-on-devices-with-1gb-ram - more-closer to Disk
5. I wanna be closer to Cloud/Net (#TODO)
6. I wanna be closer to Sun (Icarus Mode) - not planned yet

Author

V.Krishn

Resources