Make kvm2 driver disk images smaller

[afbjorklund]

Is this a BUG REPORT or FEATURE REQUEST? (choose one):

FEATURE REQUEST

Please provide the following details:

Environment:

• Minikube version (use minikube version):
  v0.28.2
• OS (e.g. from /etc/os-release):
  Ubuntu 16.04
• VM Driver (e.g. cat ~/.minikube/machines/minikube/config.json | grep DriverName):
  kvm2
• ISO version (e.g. cat ~/.minikube/machines/minikube/config.json | grep -i ISO or minikube ssh cat /etc/VERSION):
  v0.28.1
• Install tools:
• Others:

What happened:

The disk image for the minikube machine is over 5G in size, even though "only" half of that is used.

What you expected to happen:

The size of the disk image should match the contents, like it seem to be doing closer for virtualbox.

How to reproduce it (as minimally and precisely as possible):

minikube start --vm-driver kvm2

Output of minikube logs (if applicable):

Anything else do we need to know:

It could be the swap partition that is bloating the disk image, it could also be temporary files.

The workaround is to "compact" the disk image, by stopping it and using qemu-img convert

[afbjorklund]

When running Virtualbox (5.1), the minikube.vmdk is 2G for basic Kubernetes + default addons

When running libvirt (kvm2), the minikube.rawdisk is 4G for basic Kubernetes + default addons

[afbjorklund]

Running qemu-img convert on the raw image, shrinks the file size from 4.0G to 1.8G

Possibly the situation can be helped by using discard=unmap, but it remains to be seen...

https://dustymabe.com/2013/06/11/recover-space-from-vm-disk-images-by-using-discardfstrim/

$ sudo fstrim /mnt/vda1
fstrim: /mnt/vda1: the discard operation is not supported

[fejta-bot]

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[afbjorklund]

After the removal of the swap partition, the bloat is smaller but it is still there:

$ qemu-img convert -f raw minikube.rawdisk -O raw minikube.convert
$ du -hs minikube.rawdisk minikube.convert
3.0G	minikube.rawdisk
1.8G	minikube.convert

/remove-lifecycle rotten

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[k8s-ci-robot]

@fejta-bot: Closing this issue.

In response to this:

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