Snapd 2.35.2: ERROR run hook "configure": cannot set "core.schedule": unsupported system option

[arossali]

Hello,

On our board (a custom board with a dedicated gadget and kernel snaps) I see an error during a “Change configuration of core snap” action:

root@localhost:/# snap change 9
Status  Spawn               Ready               Summary
Error   today at 04:04 UTC  today at 04:04 UTC  Run configure hook of "core" snap

......................................................................
Run configure hook of "core" snap

2018-10-18T04:04:21Z ERROR run hook "configure": cannot set "core.schedule": unsupported system option

I first though about the “refresh.schedule” we set on our Gadget, but if I check is correctly set:

root@localhost:/# snap get core refresh
Key               Value
refresh.schedule  08:00-10:00

Any ideas why are we getting this error?

Thanks

[mborzecki]

It looks to me that the was an attempt to set the schedule using an command that was not correct. Please refer to System options topic for details.

TLDR

$ snap set system refresh.schedule=...

Where system is an alias for core (since 2.32.5+).

Also, you may want to consider using refresh.timer which was introduced in 2.31, consult Timer string format topic for description of the format.

[arossali]

Doing it via command line I get no Errors.
I tried:

snap set core refresh.schedule=08:00-12:00

and even:

snap set system refresh.schedule=08:00-12:00

Both work, even if snap is 2.35.2 (armhf).
Thing is, we want to rely on Gadget for this, I actually don’t know which command is used by it to set such option.
I’ll try “refresh.timer” instead of “refresh.schedule” in gadget.yaml.

Thanks!

[ogra]

Where system is an alias for core

When using the defaults: option in gadget.yaml you have to use the snap-id.
a name or alias is only working when using the snap command from cmdline… :

The gadget snap

The gadget snap is responsible for defining and manipulating the system properties which are specific to one or more devices that will usually look similar to one another from an implementation perspective. This snap must necessarily be produced and signed by the device brand, which is defined via the model assertion. The brand knows where and how that device will be used, and designs the gadget snap accordingly. For example, the brand may know that the device is actually a special VM to be use…

Do we have any generic or special snap-id for “system” ?

[mborzecki]

Do we have any generic or special snap-id for “system” ?

You can use system instead of snap-id. In fact, system takes precendence, using both snap-id of the core and the system alias will make snapd log a message and use the settings under the system key.

It’s mentioned in the docs too:

# Default configuration options for defined snaps, applied on installation.
# The snap ID may be discovered via the snap info command.
# Since 2.33 snap ID can be the "system" nick to cover the system
# configuration. (optional)
defaults:
    <snap id>:
        <key>: <value>