Examples of vAccel in Unikraft

A set of examples to test vAccel in Unikraft.

The vaccel_config file contains a config for KVM platform which enables the following libraries:

• vAccelrt (the virtio accel driver gets enabled too)
• 9pfs, so we can pass the image to the unikernel
• vfscore with 9pfs as root filesystem
• devfs which gets mounted during boot , for /dev/accel

Building using Docker

The easiest way to build a Vaccel example over Unikraft is to use docker:

DOCKER_BUILDKIT=1 docker build --network=host -f Dockerfile -t unikraft_vaccel_example --build-arg "EXAMPLE=noop" --target artifacts --output type=local,dest=./unikraft_images .

The above command will create a new directory named unikraft_images, which will contain the Unikraft image of EXAMPLE argument.

The available examples can be found using the following command:

$ bash buil_example.sh list

Building from scratch

Let's assume, that a Unikraft workspace has been created, using our Unikraft fork and specifically vaccel_rel010 branch.

The directory tree should look like that:

$ tree -L 2
.
├── apps
│   └── unikraft_vaccel_examples
├── libs
│   └── lib-newlib
└── unikraft
    ├── arch
    ├── Config.uk
    ├── CONTRIBUTING.md
    ├── COPYING.md
    ├── include
    ├── lib
    ├── Makefile
    ├── Makefile.uk
    ├── plat
    ├── README.md
    ├── support
    └── version.mk

10 directories, 8 files

In order to build an application you can use the `build_example.sh script:

$ bash build_example.sh <example_name>

The user can get the list with the available examples, with the following command:

$ bash buil_example.sh list

Otherwise, the user can build an application following the below instructions:

$ cp vaccel_config .config
$ make olddefconfig
$ make menuconfig

In the menuconfig, under the Application_Options, the user can shoose one of the available examples.

NOTE: Only one example can be used. In case that, more than one examples are slected the first one in the list will be built.

After selecting the example, the user can simply build the unikernel, with the make command.

Executing

Let's assume that a successful installation of vAccel has taken place, following the steps in vAccel's docs.

Afer building a Unikraft example you can run it using the qemu_run.sh script.

bash QEMU_BINARY=<path_to_qemu_binary> qemu_run.sh <DATA> <UNIKERNEL_IMAGE> <APP_ARGS>

The qemu_run.sh script simply executes the following command:

$QEMU_BINARY \
-cpu host -m 512 -enable-kvm -nographic -vga none \
-fsdev local,id=myid,path=$DATA,security_model=none -device virtio-9p-pci,fsdev=myid,mount_tag=data,disable-modern=on,disable-legacy=off \
-object acceldev-backend-vaccelrt,id=gen0 -device virtio-accel-pci,id=accl0,runtime=gen0,disable-legacy=off,disable-modern=on \
-kernel $UNIKERNEL_IMAGE -append "vfs.rootdev=data -- $APP_ARGS"

where:

• QEMU_BINARY is the full path of a QEMU binary, built with the vAccel bacckend
• DATA is the directory which contains the data for the example
• UNIKERNEL_IMAGE, is the path to the unikernel image
• $APP_ARGS, are the arguments for the example application