Development of Bhyve Management Daemon on FreeBSD
- 1. Development of Bhyve Management Daemon Yuichiro Naito Mar. 22, 2025
- 2. Who am I? Yuichiro Naito – Master's degree of computer science from UEC, 1998 – Software Engineer worked for PFU, 1998-2009 – Software Engineer working for SOUM, 2009- – FreeBSD user, since 2.1.6-R – FreeBSD port maintainer, 2016-
- 3. What’s the bmd? ● Management of bhyve processes. ● Invokes bhyve and boot loaders according to the configuration files. ● Wait for them and reboot if necessary. bmd bhyveload grub-bhyve bhyve fork & exec & wait
- 4. What’s the bmd? ● A command line tool: bmdctl – boot/shutdown the VM. – console access to the VM. (emulate ‘cu -l’) bmdctl bmd Unix domain socket bhyve nmdm device
- 5. Why do I develop the bmd? ● There are many bhyve management tools. – vm-bhyve – cbsd – vmstated – bhyvemgr – ... ➔ Fun of programming. ➔ Focusing my use case.
- 6. Why do I develop the bmd? ● Delegating VM operations to users. – Root privilege is too big to boot/shutdown the VMs. – I want to boot/shutdown my VMs casually. – Allow to access the VM console which I booted. ➔ The bmd identifies the VM owner and allows the VM operations.
- 7. Why do I develop the bmd? ● Dynamic tap interface assignment. – The tap interfaces can be created/destroyed dynamically. – No need static assignment. – Describe network interfaces in which bridge to be included. ➔ The bmd creates a tap interface and adds to a bridge.
- 8. Why do I develop the bmd? ● Don't repeat myself by copying the same configurations. – After many configurations are copied, I find my mistake! ➔ The template feature for the VM configuration. – I need to find unused VNC port for the new VM. ➔ Unique ID number and arithmetic calculations. ➔ e.g. $(( 5900 + $ID ))
- 9. Why do I develop the bmd? ● How do I know the VNC port? – publish via mDNS. (avahi-publish) – Bvnc (gtk), Finder (MacOS) show the list. ➔ I have no idea for Windows users.
- 10. Why do I develop the bmd? ● Auto inspection for grub-bhyve boot command. – Looking for the OpenBSD kernel. ● /bsd.upgrade or /bsd or /7.5/amd64/bsd – Looking for the NetBSD kernel. ● /netbsd – Generate the boot command. ● ‘kopenbsd …’ or ‘knetbsd …’.
- 11. VM configuration examples template mydefault(n = 2, m = 2G) { ncpu = ${n}; memory = ${m}; disk = /dev/zvol/zpool/images/${NAME}; network=bridge0; console=auto; } template grubloader { loader=grub; loadcmd=auto; installcmd=auto; }
- 12. VM configuration examples vm freebsd { .apply mydefault(4, 4G); loader=bhyveload; } vm netbsd { .apply mydefault, grubloader; } vm openbsd { .apply mydefaulft, grubloader; }
- 13. VM owner ● VM owner is as same as the file owner of the VM configurations. ● The ‘.include’ macro loads the other configuration files. – e.g. .include /home/yuichiro/bmd.conf; – The parser runs under the file owner priviledge. ● Use ‘owner’ keyword to change the owner. – e.g. owner=yuichiro;
- 14. Console access bmdctl bmd nmdm access request check cred. open & flock file descriptor file descriptor
- 15. Console access bmdctl bmd nmdm SIGTERM bhyve read write close read read exit write
- 16. bmdctl ● The same binary file as bmd. ● Internal protocol is passing nvlist structure. ● The bmdctl can run the same parser as the bmd. – It’s useful to check if the configuration files are correct. – Independent check of the running bmd.
- 17. Plugins ● avahi – publish the VNC port. ● hookcmd – invoke a command when VM state is chaned. (for reporting tasks) – invoke a command before VM starts. (for setup tasks) – invoke a command after VM stops. (for cleanup tasks) ● qemu – Use qemu instead of bhyve. (experimental)
- 18. The bmd doesn’t ● create bridge interfaces. – to avoid double management of rc scripts. ● create disk images. – Users can create a file or a zvol if the administrator allows. – Users must follow the system administration policy.
- 20. Future works ● Wake on LAN support – monitoring WoL packets on the specific bridges. – requires MAC address configuration. ● support bhyve migration – Work in progress ● AsiaBSDCon 2023 ● BSDCan 2019
- 21. Any Questions? ● Please ask me slowly.