Generate the unique machine-id from mac address

[kuanyu99]

Why I did it

1. The machine-id is generated during the building process and will be copied to each installed device. So each device will have the same id.
2. The machine-id will be different for each different image on the same device.

How I did it

1. Generate the machine-id from the eth0 MAC address during initializing the ram-file system
2. Use symbolic files target to the /run/machine-id to replace original /etc/machine-id and /var/lib/dbus/machine-id
3. Due to the existence of the symbolic files, the SONiC boot up process will be consistent after this commit. If the Linux system detect /etc/machine-id missing, it will trigger its first boot mechanism.

How to verify it

After the change, the behavior will be:

1. The machine-id will be different for each device with the same version image.
2. The machine-id will be the same for each different image on the same device.

Which release branch to backport (provide reason below if selected)

• 201811
• 201911
• 202006
• 202012
• 202106
• 202111
• 202205
• 202211

This change can fit to any release which using build_debian.sh to build the SONiC image.

Description for the changelog

• Originally, the machine-id is generated randomly during the building process. And will be copied to each device during installing.
• After this, the machine-id will be generated according to mac address which is unique for each device. And will be consistent even installing new image.

Ensure to add label/tag for the feature raised. example - PR#2174 under sonic-utilities repo. where, Generic Config and Update feature has been labelled as GCU.

Link to config_db schema for YANG module changes

A picture of a cute animal (not mandatory but encouraged)

[lguohan]

it is unclear what the machine id is used for, why unique machine id is needed.

[kuanyu99]

From the man page, https://manpages.ubuntu.com/manpages/kinetic/en/man5/machine-id.5.html
It should be unique for the local system.
And it is also a requirement from our users.

[lguohan]

i cannot agree with on current approach to use mac address and make it consistent across installation.

check the machine-id here.

https://wiki.debian.org/MachineId

It's intended as an opaque, non-human-meaningful, persistent unique identifier for a machine (or more precisely an OS installation), used as a lookup key in state/configuration storage in the same sorts of places you might be tempted to use a hostname.

generating machine-id during installation makes sense

[kuanyu99]

i cannot agree with on current approach to use mac address and make it consistent across installation.

check the machine-id here.

https://wiki.debian.org/MachineId

It's intended as an opaque, non-human-meaningful, persistent unique identifier for a machine (or more precisely an OS installation), used as a lookup key in state/configuration storage in the same sorts of places you might be tempted to use a hostname.

generating machine-id during installation makes sense

Regarding this page, I think the machine-id should be different for each version SONiC on a device.
So, instead of generating from MAC address, using a random 16 bytes id is a preferable way, right?

[CharlieChenEC]

Hi @lguohan

i cannot agree with on current approach to use mac address and make it consistent across installation.

check the machine-id here.

https://wiki.debian.org/MachineId

It's intended as an opaque, non-human-meaningful, persistent unique identifier for a machine (or more precisely an >OS installation), used as a lookup key in state/configuration storage in the same sorts of places you might be >tempted to use a hostname.

generating machine-id during installation makes sense

Actually, there is no restriction on the method to generate machine-id and no clear regulation on the life cycle of a machine-id. I think the description in https://wiki.debian.org/MachineId tells you what 'machine-id' is for and when it is generated in general, which can be considered as a guidance but not a regulation.

In https://alexforencich.com/wiki/en/linux/nfs_unique_machineid, it describes the way to generate a unique machine id in 'initramfs' stage on the machine that uses NFS as its root file system.

What is your concern if we generate the machine-id during 'initramfs' stage instead of on the 'installation' stage?

And what is your concern if the machine-id is consistent across installation? Do you have any scenario in your mind that it might cause problems if the machine-id is consistent across installation?

[CharlieChenEC]

Hi @lguohan,

May I have your comment on the solution for machine-id generation on SONiC?

I think it's OK to revise the PR to generate machine-id during the installation stage.

What about the part on the content of 'machine-id'? If you think it should not use 'mac address' to generate 'machine-id'?