Merge --mount and --mount-string flags

[medyagh]

we dont need both flags, if you provide --mount-string, it shoud also mean you want --mount to be true

and we should Deprecate --mount-string
and for users that provide the old way, we should warning and TRY to do be our best to translate

also seems like we also have mount-options (super confusing) too many mount related things

      --mount                             This will start the mount daemon and automatically mount files into minikube.
      --mount-9p-version string           Specify the 9p version that the mount should use (default "9p2000.L")
      --mount-gid string                  Default group id used for the mount (default "docker")
      --mount-ip string                   Specify the ip that the mount should be setup on
      --mount-msize int                   The number of bytes to use for 9p packet payload (default 262144)
      --mount-options strings             Additional mount options, such as cache=fscache
      --mount-port uint16                 Specify the port that the mount should be setup on, where 0 means any free port.
      --mount-string string               The argument to pass the minikube mount command on start.
      --mount-type string                 Specify the mount filesystem type (supported types: 9p) (default "9p")
      --mount-uid string                  Default user id used for the mount (default "docker")

seems like we had added mount-string in 2017 even before @tstromberg and I were in minikube

https://github.com/kubernetes/minikube/blob/master/CHANGELOG.md#version-0191---5302017

[nirs]

Plan for unified mounts as discussed in slack

minikube 1.36

Support single mount using 9p protocol:

minikube start --mount=true --mount-string /host-path:/guest-path --mount-options cache=fscache

This will not work since --mount expects an argument:

minikube start --mount --mount-string /host-path:/guest-path

Maybe we can find a way to treat --mount and --mount=true in the same way. We want to use StringArrayVar to support multiple arguments for the new way.

minikube 1.37

Support single mount using 9p protocol or virtiofs (depending on the driver):

minikube start --mount-string /host-path:/guest-path --mount-options cache=fscache

The --mount flag is silently ignored - nothing is mounted since we don't have a default value for --mount-string

minikube start --mount

New way - minikube 1.38

Drivers supporting virtiofs can accept multiple mount arguments. Other drivers can accept single mount and use 9p.

Example multiple mounts for vfkit and krunkit (using virtiofs):

minikube start --mount /host-path1:/guest-path1 --mount /host-path2:/guest-path2

Example single mount for all drivers (using virtiofs or fallback to 9p):

minikube start --mount /host-path1:/guest-path1

Using multiple mounts for drivers not supporting virtiofs will fail.

All the other --mount-* flags are not supported in this mode. Using them will fail the command.

Mount options

We support per-mount options string:

--mount HOST_PATH:GUEST_PATH[:OPTIONS]

Example mounts with per mount options:

--mount ~/models:/mnt/mdoels:ro --mount ~/project:/mnt/project

In this case /mnt/models will be readonly, and /mnt/project will be writable.

The options will be passed to guest mount command as without any change:

sudo mount -t virtiofs -o ro mount-tag1 /mnt/models
sudo mount -t virtiofs mount-tag2 /mnt/project

Passing options to 9p mount will be pass the options without change to the underling minikube mount command.

--mount ~/models:/mnt/mdoels:cache=fscache,msize=262144

Will invoke:

minikube mount ~/models:/mnt/mdoels --mount-options cache=fscache,msize=262144