Re: [libvirt] [PATCH] Make guest OS bootable when hardware failure happens in log disk

[Problem] Currently, guest OS's messages can be logged to a local disk of host OS by creating chadevs with options below. -chardev file,id=charserial0,path=<log file's path> -device isa-serial,chardev=chardevserial0,id=serial0 When a hardware failure happens in the disk, qemu-kvm can't create the chardevs. In this case, guest OS doesn't boot up. Actually, there are users who don't desire that guest OS goes down due to a hardware failure of a log disk only.Therefore, libvirt should offer some way to boot guest OS up even if the log disk is broken. [Solution] This patch changes a destination to /dev/null in case a log file can't be opened. Signed-off-by: Seiji Aguchi <seiji.aguchi(a)hds.com&gt; --- src/qemu/qemu_process.c | 20 +++++++++++++++++++- 1 files changed, 19 insertions(+), 1 deletions(-) diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c index 8c4bfb7..fdf26ad 100644 --- a/src/qemu/qemu_process.c +++ b/src/qemu/qemu_process.c @@ -2440,7 +2440,25 @@ qemuProcessPrepareChardevDevice(virDomainDefPtr def ATTRIBUTE_UNUSED, virReportSystemError(errno, _("Unable to pre-create chardev file '%s'"), dev->source.data.file.path); - return -1; + VIR_FREE(dev->source.data.file.path); + /* + * Change a destination to /dev/null to boot guest OS up + * even if a log disk is broken. + */ + dev->source.data.file.path = strdup("/dev/null"); + + if (!dev->source.data.file.path) { + virReportOOMError(); + return -1; + } + + if ((fd = open(dev->source.data.file.path, + O_CREAT | O_APPEND, S_IRUSR|S_IWUSR)) < 0) { + virReportSystemError(errno, + _("Unable to pre-create chardev file '%s'"), + dev->source.data.file.path); + return -1; + } }