Add --extra-disks capability to kvm2 driver

[raghavendra-talur]

Having additional disks on the nodes is a requirement for developers
working on the storage components in Kubernetes. This commit adds the
extra-disks feature to the kvm2 driver.

Output:

$ minikube start --profile msecondary --driver=kvm2 --network=mk-default --nodes=2 --extra-disks=3 --addons=olm
😄  [msecondary] minikube v1.22.0 on Fedora 34
    ▪ KUBECONFIG=/home/rtalur/.kube/config
✨  Using the kvm2 driver based on user configuration
👍  Starting control plane node msecondary in cluster msecondary
🔥  Creating kvm2 VM (CPUs=4, Memory=16384MB, Disk=20000MB) ...
🐳  Preparing Kubernetes v1.21.3 on Docker 20.10.8 ...
❌  Unable to load cached images: loading cached images: stat /home/rtalur/.minikube/cache/images/docker.io/kubernetesui/dashboard_v2.1.0: no such file or directory
    ▪ Generating certificates and keys ...
    ▪ Booting up control plane ...
    ▪ Configuring RBAC rules ...
🔗  Configuring CNI (Container Networking Interface) ...
🔎  Verifying Kubernetes components...
    ▪ Using image quay.io/operator-framework/olm:v0.17.0
    ▪ Using image quay.io/operator-framework/upstream-community-operators:07bbc13
    ▪ Using image gcr.io/k8s-minikube/storage-provisioner:v5
🌟  Enabled addons: storage-provisioner, default-storageclass, olm

👍  Starting node msecondary-m02 in cluster msecondary
🔥  Creating kvm2 VM (CPUs=4, Memory=16384MB, Disk=20000MB) ...
🌐  Found network options:
    ▪ NO_PROXY=192.168.39.145
🐳  Preparing Kubernetes v1.21.3 on Docker 20.10.8 ...
    ▪ env NO_PROXY=192.168.39.145
🔎  Verifying Kubernetes components...

❗  /home/rtalur/.local/bin/kubectl is version 0.21.0-beta.1, which may have incompatibilites with Kubernetes 1.21.3.
    ▪ Want kubectl v1.21.3? Try 'minikube kubectl -- get pods -A'
🏄  Done! kubectl is now configured to use "msecondary" cluster and "default" namespace by default

Devices in the VMs:

$ minikube --profile msecondary node list
msecondary      192.168.39.145
msecondary-m02  192.168.39.92
{0} 14:57:31 rtalur@rastartower [~]
$ minikube --profile msecondary ssh -- lsblk
NAME   MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
vda    253:0    0 19.5G  0 disk
`-vda1 253:1    0 19.5G  0 part /mnt/vda1
vdb    253:16   0 19.5G  0 disk
vdc    253:32   0 19.5G  0 disk
vdd    253:48   0 19.5G  0 disk
{0} 14:57:43 rtalur@rastartower [~]
$ minikube --profile msecondary ssh --node msecondary-m02 -- lsblk
NAME   MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
vda    253:0    0 19.5G  0 disk
`-vda1 253:1    0 19.5G  0 part /mnt/vda1
vdb    253:16   0 19.5G  0 disk
vdc    253:32   0 19.5G  0 disk
vdd    253:48   0 19.5G  0 disk

Disk files on the host with the VM running and after the cleanup:

$ ls -lash ~/.minikube/machines/msecondary/*.rawdisk
4.0K -rw-r--r--. 1 qemu qemu 20G Aug 25 14:50 /home/rtalur/.minikube/machines/msecondary/msecondary-0.rawdisk
4.0K -rw-r--r--. 1 qemu qemu 20G Aug 25 14:50 /home/rtalur/.minikube/machines/msecondary/msecondary-1.rawdisk
4.0K -rw-r--r--. 1 qemu qemu 20G Aug 25 14:50 /home/rtalur/.minikube/machines/msecondary/msecondary-2.rawdisk
4.0G -rw-r--r--. 1 qemu qemu 20G Aug 25 14:59 /home/rtalur/.minikube/machines/msecondary/msecondary.rawdisk
{0} 14:59:20 rtalur@rastartower [~]
$ minikube --profile msecondary delete
🔥  Deleting "msecondary" in kvm2 ...
🔥  Deleting "msecondary-m02" in kvm2 ...
💀  Removed all traces of the "msecondary" cluster.
{0} 14:59:59 rtalur@rastartower [~]
$ ls -lash ~/.minikube/machines/msecondary/*.rawdisk
ls: cannot access '/home/rtalur/.minikube/machines/msecondary/*.rawdisk': No such file or directory

Signed-off-by: Raghavendra Talur raghavendra.talur@gmail.com

[k8s-ci-robot]

Hi @raghavendra-talur. Thanks for your PR.

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[minikube-bot]

Can one of the admins verify this patch?

[medyagh]

nice work @raghavendra-talur do u mind adding in the PR description out of of example of using this PR ? and verifying the Disk was created ?

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: medyagh, raghavendra-talur

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[raghavendra-talur]

@medyagh Thanks for the quick review. I have updated the description with the output info.

@BlaineEXE Thanks for #11483. The blueprint helped a lot.

[BlaineEXE]

Thanks @raghavendra-talur for implementing this for kvm (Linux). I think having Linux and MacOS support for the feature is really good coverage as far as overall usability is concerned. Especially since KVM and Hyperkit are very fast hypervisors for their respective platforms.

And thanks @medyagh for being open to the feature in Minikube. This is going to make our documentation for helping users get started working on Rook a lot easier.

I don't have any time in the near future, but I think the final driver that would extend feature coverage to Windows users (a small user base I imagine) is to add support for VirtualBox. This driver is also supported on Linux and MacOS and so would add overlapping support to give users some more choice. Though with the new-ish Windows Subsystem for Linux, that might not even be a concern. Medya might have more insight into whether there are other Minikube drivers that would be beneficial to focus on.

[kfox1111]

@BlaineEXE With docker for desktop not being free anymore, the windows userbase may start growing.