Should I overwrite default cloud.cfg from cloud VPS provider

Generally, should I overwrite default cloud.cfg from cloud VPS provider when prompted after run apt upgrade?

This is the differences:

--- /etc/cloud/cloud.cfg        2021-11-06 07:20:42.239580730 +0000
+++ /etc/cloud/cloud.cfg.dpkg-new       2021-10-07 16:51:28.000000000 +0000
@@ -71,6 +73,8 @@
  - chef
  - mcollective
  - salt-minion
+ - reset_rmc
+ - refresh_rmc_and_interface
  - rightscale_userdata
  - scripts-vendor
  - scripts-per-once
@@ -108,7 +112,7 @@
    package_mirrors:
      - arches: [i386, amd64]
        failsafe:
-         primary: http://mirrors.idcloudhost.com/ubuntu
+         primary: http://archive.ubuntu.com/ubuntu
          security: http://security.ubuntu.com/ubuntu
        search:
          primary:

The only thing I understand is they using their own ubuntu mirror instead of official one, but I dont understand why they dont have reset_rmc and refresh_rmc_and_interface

does cloud-init run every boot? every system upgrade? or what?

EDIT 1: ok so apparently cloud-init will run again if I do cloud-init clean and then reboot?

It looks like your VPS includes cloud-init, but then overwrites some things in their default image. Applying the change listed here shouldn't hurt anything unless you're running on an IBM PowerVM Hypervisor. The rmc modules are specific to IBM PowerVM Hypervisor and won't get invoked unless you have rmcctrl installed on your system. I'm not really sure why the VPC decided to remove them.

Cloud-init runs every boot, but it skips most setup and modules after the first boot. https://cloudinit.readthedocs.io/en/latest/topics/modules.html# lists all modules (minus the IBM-specific ones as they're not configurable), and you can see a module frequency for every module. Only modules that specify always will run every boot.

Yes, running cloud-init clean (usually with --logs) will clear all cloud-init state and run it again on reboot as if it were first boot.