[systemd-devel] machinectl: Support for cache cleaning

[Peter Paule]

Hi Lennart,

after getting the "Permission Denied"-error mentioned in one of my  
previous mails,
which went away when running "importd" under root:

   Got 1% of  
https://registry-1.docker.io/v1/images/e03153f199183f91a9ee47334e65c7155d8619ef35c8158da80d0790af05ad98/layer. 2min 50s left at  
187.0K/s.
   tar: usr/sbin/nginx: Cannot open: Permission denied
   tar: usr/bin/gmake: Cannot create symlink to ‘make’: Permission denied
   tar: usr/bin/make: Cannot open: Permission denied
   tar: usr/bin/openssl: Cannot open: Permission denied
   tar: usr/bin/gtar: Cannot create symlink to ‘tar’: Permission denied
   tar: usr/bin/tar: Cannot open: Permission denied

I asked myself how I can get rid of those broken "temporary"  
subvolumes, to re-pull the image:

   drwxr-xr-x  1 root root  158 Feb 20 18:46  
.dkr-00b2b6c6a2f93b2dde1d46b06cff32de82dabfd3b5ac6a8f27c5064f429e3e7a
   drwxr-xr-x  1 root root  158 Feb 20 18:46  
.dkr-052665c23d7f38d475095f383196c5bf0b13dafe8b7fd02e3a4926767f839e95
   drwxr-xr-x  1 root root  158 Feb 20 18:46  
.dkr-0a6d917a8308476a069be3411d5aefddd34a9d4b3342e5deee5922b9a3abfa14
   drwxr-xr-x  1 root root  158 Feb 20 18:46  
.dkr-0a9465a17f988e749d3c217ecfd935a093789e7489a3516a7eedd17492b556d9

Do you plan to add a "cache" cleansing command to machinectl? I think  
now only "btrfs
subvolume delete" will do the trick, correct?

Can I delete those subvolumes safely without losing any data? Now I've  
got only
only one container running, so I can be pretty sure to delete the correct
volumes, but the situation will get a little more complex when I add more and
more images/containers. And I'm a little bit concerned about running  
out of storage,
when not cleaning up the "temporary" subvolumes regularly.

Thanks a lot.

/pp