Missing feature: show the spec of a MIG profile

[kpouget]

It would be nice if we could the tool to query content of a configuration file (most important is the 2nd command):

# nvidia-mig-parted show -f examples/config.yaml
version: v1
mig-configs:
  - all-disabled
  - all-enabled
  -  ...

# nvidia-mig-parted show -f examples/config.yaml -c all-balanced
version: v1
all-balanced:
  - devices: all
    mig-enabled: true
    mig-devices:
      "1g.5gb": 2
      "2g.10gb": 1
      "3g.20gb": 1

along with nvidia-mig-parted export, this would allow a script to detect if applying a profile would change the state of mig-enabled property

[elezar]

Thanks @kpouget. When I read:

this would allow a script to detect if applying a profile would change the state of mig-enabled property

I immediately think of something like a dry-run mode or behaviour similar to terraform plan that previews the changes between what the current state is and what the desired state is.

I don't see how the show command indicates whether the mig-enabled property would change as it does not seem to query the current state.

update: ok, I get it, one would also export the current state and then diff the output from show.

[kpouget]

yes, it looks like a dry-run, the only thing is that I don't expect the output of a --dry-run command to be yaml-parseable, while export and show have a single purpose, so it's easier to guarantee that they output proper yaml

[klueska]

I was already planning to add something to be able to check if a config exists in the config file so I can bail out early if a user asks for a mig configuration that is not there. I think this would serve that purpose as well since a call to something like:

# nvidia-mig-parted show -f examples/config.yaml -c non-existent-config

Would presumably throw an error saying that the requested config does not exist

[klueska]

That said -- the functionality you are asking for @kpouget seems to already be there with the assert command.

To detect if applying a profile would change the state of mig-enabled, you would run:

nvidia-mig-parted assert --mode-only -f examples/config.yaml -c all-1g.5gb

If this throws an error, then at least one of the mode settings in all-1g.5gb is different than what is currently applied on the node.

[klueska]

Here is an example of where I use assert for exactly this purpose in the systemd service:
https://github.com/NVIDIA/mig-parted/blob/master/deployments/systemd/service.sh#L30

[klueska]

This usage of assert used to actually be part of the README, but was removed recently:
aa797d8#diff-b335630551682c19a781afebcf4d07bf978fb1f8ac04c6bf87428ed5106870f5L127

[kpouget]

Here is an example of where I use assert for exactly this purpose in the systemd service:
https://github.com/NVIDIA/mig-parted/blob/master/deployments/systemd/service.sh#L30

hum, nice,
actually it's this service.sh script that I need to use to perform the reconfiguration, not directly nvidia-mig-parted

[klueska]

That script is used when the node i first coming online at bootup.

This script is used while a node is up and running to change the config:
https://github.com/NVIDIA/mig-parted/blob/master/deployments/systemd/apply-config.sh