So I can see that this job ran in yokobue agent at 29 Aug 2019, 5:35:42 PM (UTC time).
The messages are pretty helpful,
error: file write error (No space left on device) and
fatal: write error: No space left on device, which clearly indicate that yokobue ran out of disk (no idea what lead you to think that we had memory problems).
So, getting that data for the last 7 days:
Indeed, somehow 9:00am on the 29th (UTC) something started using a lot more disk than usual (and it went back to normal around 10pm same day).
Now, I did receive an alarm, but those are the ones I’m just going to check in a couple of days, if they are still complaining. So I didn’t really do anything, and it self resolved before I checked it.
Again, this investigation is only possible because you linked the CI build. It’s impossible to investigate without a proper link and all the logs.