Date: Wed, 13 Apr 2016 13:55:22 +0300 From: Roman Bogorodskiy <bogorodskiy@gmail.com> To: freebsd-virtualization@FreeBSD.org Subject: Understanding Bhyve shutdown Message-ID: <20160413105520.GB84953@dev.san.ru>
index | next in thread | raw e-mail
Hi, I was trying to get better understanding of how to properly shutdown VMs in bhyve, but unfortunately the documentation does not provide much details on that. Specifically, handbook [I] suggests to reboot a machine and then run bhyvectl --destroy on it. The bhyvectl(8) manpage mentions the '--force-reset' and '--force-poweroff' switches, but does not give details on those. I: https://www.freebsd.org/doc/handbook/virtualization-host-bhyve.html I tried all the options I know and wrote down the results. I also have some questions, hopefully you'll be able to answer some of them. 1. bhyvectl --vm=$name --destroy * looks like hard poweroff in the guest * the corresponding bhyve(8) process goes away * /dev/vmm/ entry goes away In my experience, it's a dangerous way to shutdown a VM because sometimes it appears it damages the image and VM fails to boot with something like this: --- Starting devd. mode = 0100600, inum = 170269, fs = / panic: ffs_valloc: dup alloc cpuid = 0 KDB: stack backtrace: #0 0xffffffff80984e30 at kdb_backtrace+0x60 #1 0xffffffff809489e6 at vpanic+0x126 #2 0xffffffff809488b3 at panic+0x43 #3 0xffffffff80b74a6e at ffs_valloc+0x84e #4 0xffffffff80bb60ad at ufs_makeinode+0x7d #5 0xffffffff80bb24fd at ufs_create+0x2d #6 0xffffffff80e71841 at VOP_CREATE_APV+0xa1 #7 0xffffffff809cd9e6 at uipc_bindat+0x346 #8 0xffffffff809c5488 at kern_bindat+0x108 #9 0xffffffff809c52a7 at sys_bind+0x77 #10 0xffffffff80d4b3f7 at amd64_syscall+0x357 #11 0xffffffff80d30adb at Xfast_syscall+0xfb Uptime: 3s Dump failed. Partition too small. --- 2. kill -SIGTERM $bhyve_pid If guest supports ACPI shutdown: * guest shuts down cleanly * the corresponding bhyve(8) process terminates * /dev/vmm entry is still here, need bhyvectl --destroy for complete cleanup If guest does not support ACPI shutdown (such as doing sysctl hw.acpi.power_button_state=NONE): * Nothing happens Q1: Is there a way to know if a guest reacted to power button but waiting for the bhyve process to terminate? Q2: Why it's not done via bhyvectl (it seems that it's easier for users + don't have to overload a useful SIGTERM signal) 3. bhyvectl --vm=$name --force-poweroff * looks like hard poweroff in the guest * the corresponding bhyve(8) process goes away * /dev/vmm entry is still here, need bhyvectl --destroy for complete cleanup Q: what's the practical difference with just doing --destroy right away? 4. bhyvectl --vm=$name --force-reset Looks very similar to item #3 with just different exit code (reboot appears to be using 0, while shutdown and halt use 1 and 2). Q: what's the practical use of it? Would greatly appreciate if somebody could provide more details on that. I guess we'll need to update Handbook with this information as well because it needs to mention SIGTERM for ACPI shutdown at least. Roman Bogorodskiyhome | help
Want to link to this message? Use this
URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20160413105520.GB84953>