Porting of $\mu$CernVM to AArch64

$\mu$CernVM is a virtual appliance that contains a stripped-down Linux OS connecting to a CernVM-Filesystem (CVMFS) repository that resides on a dedicated web server. In contrast to “usual” VMs, anything that is needed from this repository is only downloaded on demand, aggressively cached and eventually released again. Currently, $\mu$CernVM is only distributed for x86-64. Recently, ARM (market leader in mobile computing) has started to enter the server market, which is still dominated by x86-64 infrastructure. However, in terms of performance/watt, AArch64 (latest ARM 64bit architecture) is a promising alternative. Facing millions of jobs to compute every day, it is thus desirable to have an HEP virtualisation solution for AArch64. In this project, $\mu$CernVM was successfully ported to AArch64. Native and virtualised runtime performance was evaluated using ROOT6 and CMS benchmarks. It was found that VM performance is inferior to host performance across all tests. Respective numbers greatly vary between ROOT6 and CMS benchmarks. It is recommended to run further test benchmarks under varying conditions (VM or host configurations, load configurations, parallel threads etc.) to gain more insight into current bottlenecks. The next step is to get the image running on cloud infrastructure, preferably OpenStack. In regard to porting $\mu$CernVM to other architectures, we now have some experience and empirical values of how much effort is involved. The entire work is merged upstream.