Rapido helps you quickly test Linux kernel changes.
The scripts that make up Rapido are in themselves quite brainless. Most of the heavy lifting is instead performed by:
- Dracut:
- Generates a VM image, with kernel-modules and minimal user-space
- QEMU:
- Boots a given Dracut VM image and compiled Linux kernel on the local system
- systemd-networkd:
- Configures networking within Rapido VMs (optional)
- iproute2:
- Configures Bridge and TAP devices on the host (optional)
Dependencies are obtained from the local system; no magic images or internet downloads are necessary.
Once the dependencies listed above have been installed, Rapido can be configured via rapido.conf. At a minimum, the Linux kernel source parameters should be defined.
Test VM images may be "cut" with or without network support. For
networking, per-VM systemd-networkd configuration should be specified in
the net-conf directory. An example is provided in
net-conf.example.
The rapido setup-network command should be run as root to configure a
bridge network device and VM-assigned tap devices.
By default, the bridge network is isolated, and isn't connected to any
physical adapters.
Depending on which kernel component or functionality you'd like to test,
choose a cut script to generate a VM image. E.g.
./rapido cut fstests-btrfsThe cut script collects all required kernel modules and user-space dependencies
from the local system and writes a VM initramfs image to initrds/myinitrd.
Once generated, a VM using the image and kernel will boot immediately.
Subsequent VMs can be booted manually via:
./rapido bootRapido can be easily extended to test any kernel functionality of interest. Simply copy the cut/simple_example.sh and autorun/simple_example.sh scripts and modify them to suit your needs. The example scripts are fully annotated.
Please raise any questions or issues upstream via https://github.com/rapido-linux/rapido/issues
ASCII art
+------------------------+
| |
| Rapido 'cut' script |
| |
| +--------------------+ | +-----+
| | | | | |
| | File manifest: | | | |
+------------------------+ | | • Kernel modules | | | |
| | | | • User space files | | | |
| Userspace dependencies | | | | | | |
| E.g. | | +---------+----------+ | | |
| • xfstests, blktests | | | <----+ |
| • Ceph conf + binaries | | +---------v----------+ | | |
| • Samba | | | | | | |
| • etc. +--->--+----> Dracut initramfs | | | r |
| | | | | generator | | | a |
+------------------------+ ^ | | | | | p |
| | +---------+----------+ | | i |
+-------------------------+ | | | | | d |
| | | +------------------------+ | o |
| Rapido 'autorun' script +-->--+ | | . |
| | | +---------v----------+ | c |
+-------------------------+ | | | | o |
| | Initramfs | | n |
^ | • Includes all | | f |
+------------------------+ | | kernel and user | | |
| Compiled Linux Kernel | | | dependencies | | / |
| | | | | | |
| +---------+ | | +---------+----------+ | n |
| | Modules +---------------->--+ | | e |
| +---------+ | +------------------------+ | t |
| | | | | | |
| +---------+ | | Rapido 'vm' script | | c |
| | bzImage +---------------->--+ | | | | o |
| +---------+ | | | +--------v----+ | | n |
| | | | | | <----+ f |
+------------------------+ +-----> QEMU / KVM | | | |
| | | | | |
| +--------+----+ | | |
| | | +--+--+
+------------------------+ |
=================== | |
| Virtual network O--------+ +-----------v---------------+ v
=========^========= | ++ | |
| | !| Virtual Machine | |
| | !| • Console redirected via | |
| +---oO stdin and stdout <----+
+-----------+------------+ !| • 'autorun' script | |
| | !| executed on boot | |
| Rapido "setup-network" | !| | v
| | !+--------------------------++ |
+-----------^------------+ +~~~~~~~~~~~~~~~~~~~~~~~~~~~+ |
| |
+------------------------------<------------------------+