Sharing $HOME folder

seamlessly share a /home/user directory between two Linux computers - ChatGPT

First idea was to share the full ~/ folder through nfs.

login will be completly stuck if the nfs server is unreachable
they are some race conditions (not so sure what) when connecting from ssh that made that solution unstable.

And there was also some other drawbacks ⚠️

ssh keys will be shared ash well
- to be able to connect to other system own key need to be added to ~/.ssh/authorized_keys
firefox will refuse to start thinking it’s already started

It is advise to enable different config between the two system (missing application / different version)

consider using a dotfile manager (like chezmoi or yadm) to manage user-specific configs smartly

Now moving to an alternative approach. There are 2 Scenarios to consider

~/	Exec on Host	remote Exec
.config	chezmoi	same
Files	local1	local2
Folder	autofs	same
Nix package	local1	local2
base system	local1	local2

Using chezmoi synchronisation is not automatic, but is still easy.
Folder autofs is cumbersome, but done very few time. It also provide a kind of sandboxing, exposing only what is required for processing on other computer

.config

Using dotfiles and chezmoi - helps you manage your personal configuration files (dotfiles, like ~/.gitconfig) across multiple machines. - install .dotfile from a git repo on a new empty machine - easy update - choose which file are managed by chezmoi

example Adding `~/.config/nix

$ chezmoi add .config/nix/nix.conf

see also
One other possibility (dismissed)

kyrat - A simple ssh wrapper script that brings your dotfiles always with you on Linux. kyrat can transfer to the remote host and source the following dotfiles
- bashrc
Volatile Dotfiles over SSH - discussion about various tools that can be helpfull (lnk) / stow

Files

This can be covered by

chezmoi but with no automatic synchronisation.
rsync if prefered

Which file needs to be syncrhonized anyway?

One easy restriction policy is that

~/ root is private to each host,
don’t write any shared files there and keep writing to autofs folder for sync

Folder

Any ~/folder can be covered by autofs. But you have to use direct map Configuration

Working example

Modify auto.master & _auto.yves

# auto.master
# direct map
/-    /etc/auto.yves	--ghost,--timeout=30

# /etc/auto.yves
/home/yves/Documents/  -fstype=nfs,rw,nosuid,nodev    yves-huv:/home/yves/Documents/
/home/yves/Videos/  -fstype=nfs,rw,nosuid,nodev    yves-huv:/home/yves/Videos/

Check that it works

$ sudo systemctl restart autofs
$ ls ~/Documents
$ ls ~/Videos

Non working Example

This setup will prevent tools like kitty ssh to work, because nothing can be written on ~/ directly, only mounted folder (~/Documents,~/Videos) are accessible.

If for simplifying configuration we let autofs handle the ~/, it will hide everything except the automounted folder.

Mouting

~/Documents → /export/media/docs
~/Video → /export/media/videos

Modify auto.master & _auto.yves

# auto.master
/home/yves    /etc/auto.yves

# auto.yves
Documents  -fstype=nfs,rw,nosuid,nodev    yves-huv:/home/yves/Documents
Videos     -fstype=nfs,rw,nosuid,nodev    yves-huv:/home/yves/Videos

Check that it works

$ sudo systemctl restart autofs
$ ls ~/Documents
$ ls ~/Videos

Fixing IP

To make the /home folder available reachable, ip of the server must be fixed, cf:

add a 2nd ip for a laptop
- this is dependant of the interface: changing a usb dongle will hide it.
setup a static ip for a server

Usage

Some example of configuration usage makint usefull to share $HOME hosted on huv (laptop) with lab (more powerfull server).

see Homelab