Cozart: Mozart for OS Kernel Configuration

[SIGMETRICS'20] Set the Configuration for the Heart of the OS: On the Practicality of Operating System Kernel Debloating [pdf]

What's the problem?

We find that less than 20% of an Ubuntu kernel is used for running a HTTP server. Lots of modules(features) are not used and they can be disabled by configurations. However, Linux has so many options and the number of options is still growing... Since it is not practical to spend hours to reconfigure the kernel every time we deploying an application, we need an automatic tool that specialize the bloated kernels.

| Version | # Options | |:--------:| -------------:| | 3.0 | 11,328 | | 4.0 | 14,406 | | 5.0 | 16,527 |

What can Cozart do?

Cozart generates APPLETS for each applications and BASELETS for each deployment environment. Cozart then can compose one BASELET and one or multiple APPLETS to generate the final configuration.

How can I use Cozart?

Setup

git clone git@github.com:hckuo/Cozart.git
cd Cozart/docker;
docker build -f Dockerfile -t cozart-env:latest .

Run

cd Cozart # project root directory
docker run -v $PWD:/Cozart --privileged -it --name cozart cozart-env /bin/bash # start up the docker container 

In docker container

mknod /dev/loop0 b 7 0 # create loop device if not exist
cd /Cozart
source constant.sh
make $mnt; make $disk # set-up mnt folder and qemu disk
make setup-qemu # patch the qemu to enable PC tracing
make setup-linux # clone the linux source
make build-db # parse the linux source to extract the relationships between the configuration options and code
make debootstrap # create a rootfs for the VM
make build-base # build the vanilla kernel as the baseline
./install_mysql_host.sh # only required for mysql
./job.sh trace boot # generate a baselet
./job.sh trace apache # generate an applet for apache (the executed workload in the VM is in /benchmark-scripts/apache.sh)
./job.sh compose apache # compose apache applet with boot baselet
./job.sh benchmark apache # benchmark the debloated kernel

Questions

If you have any questions, please let me know at hckuo2@illinois.edu. Any feedbacks (good or bad) are also welcomed.

Test coverage data in the paper