HermitCore - A lightweight extreme-scale satellite kernel

The project HermitCore has just initiated and is unikernel for high-performance computing. HermitCore extends the multi-kernel approach and combines it with unikernel features while providing better programmability and scalability for hierarchical systems. By starting a HermitCore applications, cores will be split off from the Linux system and the applications run bare-metal on these cores. This promise a lower OS jitter and a better scalability. Between HermitCore applications and the Linux system exist an IP interface, which could be used for inter-kernel communication.

HermitCore is the result of a research project at RWTH Aachen University and is currently an experimental approach and not production ready. Please use it carefully.

Requirements

• Netwide Assembler (NASM)
• GNU Make, GNU Binutils
• Tools and libraries to build linux, binutils and gcc (e.g. flex, bison, MPFR library, GMP library, MPC library, ISL library)
• libelf
• texinfo
• Qemu

Building and testing HermitCore within a virtual machine

1. The build process works currently only on x86-based Linux systems.
2. To configure the system, run the configure script in the directory, which contains this README. Fine tuning of the installation directories e.g. with the flag --prefix is currently not supported. HermitCore, the cross-compiler and the demo applications will be installed in subdirectories of this repository.
3. The command make build the Linux kernel, the HermitCore kernel, the corss-compiler and the demo applications.
4. To start a virtual machine and to boot a small Linux version use the command make qemu. Per default, the virtual machine has 10 cores, 2 NUMA nodes and 8 GByte RAM. To increase or to decrease the machine size, the label qemu in the Makefile has to be modified.
5. Afterwards, a small Linux system should run, which already includes the patches for HermitCore. For each NUMA node (= HermitCore isle) is in /sys/hermit a directory isleX created, where X represents the number of the NUMA node. The demo applications are located in the directory /hermit and possess the file extension _proxy. These applications are Linux proxies, in which the HermitCore binaries are embedded. By starting the Linux proxies, the embedded HermitCore binaries will be automatically started on isle 0 with cpu 1. To change the default behavior, the environment variable HERMIT_ISLE is used to specify the (memory) location of the isle, while the environment variable HERMIT_CPUS is used to specify the cores. For instance, HERMIT_ISLE=1 HERMIT_CPUS="3-5" /hermit/usr/hello starts a HelloWorld demo on the HermitCore isle 1, which used the cores 3 to 5. The output messages are forwarded to the Linux proxy and printed on the Linux system.
6. HermitCore's kernel messages of isleX are available via cat /sys/hermit/isleX/log, where X represents the isle.
7. It exists an virtual IP devices between HermitCore isles and the Linux system (see output of ifconfig). Per default, the Linux system has the IP address 192.168.28.1. The HermitCore isles starts with the IP address 192.168.28.2 for isle 0 and is increased by one for every isle.
8. Hermit applications are available at /hermit/usr/{tests,benchmarks} which is a shared directory between the host and QEmu.

Building and testing HermitCore on a real machine

1. In principle you have to follow the tutorial above. After the configuration (step 2 in the above tutorial) go to the subdirectory linux, which contains the source code of the Linux kernel. Configure the kernel with make menuconfig for your system. Be sure, that the option CONFIG_HERMIT_CORE in Processor type and features is enabled.
2. Go back to the root directory of this repository and build with make the Linux kernel, the HermitCore kernel, the cross-compiler and the demo applications.
3. Install the Linux kernel and its initial ramdisk on your system (see descriptions of your Linux distribution).
4. Register the HermitCore loader to your system with following command: echo ":hermit:M:7:\\x42:/path2proyxy/proxy:" > /proc/sys/fs/binfmt_misc/register, in which path2proxy defines the path to the loader. You find the loader proxy after building the HermiCore sources in the subdirectory hermit/tools of the directory, which contains this README.
5. The IP device between HermitCore and Linux does currently not support IPv6. Consequently, disable IPv6 by adding following line to /etc/sysctl.conf: net.ipv6.conf.eth0.disable_ipv6 = 1.
6. Per default, the IP device uses a static IP address range. Linux has to use 162.168.28.1, where HermitCore isles start with 192.168.28.2 (isle 0). The network manager must be configured accordingly and consequently the file /etc/sysconfig/network-scripts/ifcfg-mmnif must be created with following contents:

DEVICE=mmnif
BOOTPROTO=none
ONBOOT=yes
NETWORK=192.168.28.0
NETMASK=255.255.255.0
IPADDR=192.168.28.1
NM_CONTROLLED=yes

Finally, boot your system with the new Linux kernel and follow the above tutorial (Building and testing HermitCore within a virtual machine) from point 5.

The demo applications are stored in their subdirectories hermit/usr/{tests,benchmarks} of the directory, which contains this README.