Re: [libvirt] [PATCH] Introduce startupPolicy for chardev to make guest OS bootable when hardware failure happens in log disk

Any comments?

> -----Original Message----- > From: Seiji Aguchi > Sent: Thursday, May 02, 2013 1:26 PM > To: libvir-list(a)redhat.com > Cc: dle-develop(a)lists.sourceforge.net; Tomoki Sekiyama (tomoki.sekiyama(a)hds.com) > Subject: [PATCH] Introduce startupPolicy for chardev to 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, qemu should offer some way to boot guest OS up even if the log > disk is broken. > > [Solution] > This patch supports startupPolicy for chardev. > > The starupPolicy is introduced just in case where chardev is "file" > because this patch aims for making guest OS boot up when a hardware failure happens. > > In other cases ,pty, dev, pipe and unix, it is not introduced > because they don't access to hardware. > > The policy works as follows. > - If the value is "optional", guestOS boots up by dropping the chardev. > - If other values are specified, guestOS fails to boot up. (the default) > > Description about original startupPolicy attribute: > http://libvirt.org/git/?p=libvirt.git;a=commitdiff;h=e5a84d74a2789a917bf3... > > Signed-off-by: Seiji Aguchi <seiji.aguchi(a)hds.com&gt; > --- > docs/formatdomain.html.in | 9 ++++++++- > docs/schemas/domaincommon.rng | 3 +++ > src/conf/domain_conf.c | 8 ++++++++ > src/conf/domain_conf.h | 1 + > src/qemu/qemu_process.c | 25 ++++++++++++++++++++++++- > tests/virt-aa-helper-test | 3 +++ > 6 files changed, 47 insertions(+), 2 deletions(-) > > diff --git a/docs/formatdomain.html.in b/docs/formatdomain.html.in > index f325c3c..1e1bf27 100644 > --- a/docs/formatdomain.html.in > +++ b/docs/formatdomain.html.in > @@ -4044,13 +4044,20 @@ qemu-kvm -net nic,model=? /dev/null > <p> > A file is opened and all data sent to the character > device is written to the file. > + It is possible to define policy whether guestOS boots up > + if the file is not accessible. This is done by a startupPolicy > + attribute: > + <ul> > + <li>If the vaule is "optional", guestOS boots up by dropping the file.</li> > + <li>If other values are specified, guestOS fails to boot up. (the default)</li> > + </ul> > </p> > > <pre> > ... > &lt;devices&gt; > &lt;serial type="file"&gt; > - &lt;source path="/var/log/vm/vm-serial.log"/&gt; > + &lt;source path="/var/log/vm/vm-serial.log" startupPolicy="optional"/&gt; > &lt;target port="1"/&gt; > &lt;/serial&gt; > &lt;/devices&gt; > diff --git a/docs/schemas/domaincommon.rng b/docs/schemas/domaincommon.rng > index 10596dc..6fc0a3c 100644 > --- a/docs/schemas/domaincommon.rng > +++ b/docs/schemas/domaincommon.rng > @@ -2706,6 +2706,9 @@ > </optional> > <optional> > <attribute name="path"/> > + <optional> > + <ref name='startupPolicy'/> > + </optional> > </optional> > <optional> > <attribute name="host"/> > diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c > index a8b5dfd..6680f15 100644 > --- a/src/conf/domain_conf.c > +++ b/src/conf/domain_conf.c > @@ -6467,6 +6467,7 @@ virDomainChrSourceDefParseXML(virDomainChrSourceDefPtr def, > char *path = NULL; > char *mode = NULL; > char *protocol = NULL; > + char *startupPolicy = NULL; > int remaining = 0; > > while (cur != NULL) { > @@ -6487,6 +6488,9 @@ virDomainChrSourceDefParseXML(virDomainChrSourceDefPtr def, > !(flags & VIR_DOMAIN_XML_INACTIVE))) > path = virXMLPropString(cur, "path"); > > + if (startupPolicy == NULL && > + def->type == VIR_DOMAIN_CHR_TYPE_FILE) > + startupPolicy = virXMLPropString(cur, "startupPolicy"); > break; > > case VIR_DOMAIN_CHR_TYPE_UDP: > @@ -6559,6 +6563,10 @@ virDomainChrSourceDefParseXML(virDomainChrSourceDefPtr def, > > def->data.file.path = path; > path = NULL; > + > + def->data.file.startupPolicy = > + virDomainStartupPolicyTypeFromString(startupPolicy); > + startupPolicy = NULL; > break; > > case VIR_DOMAIN_CHR_TYPE_STDIO: > diff --git a/src/conf/domain_conf.h b/src/conf/domain_conf.h > index 3a0f23a..e709951 100644 > --- a/src/conf/domain_conf.h > +++ b/src/conf/domain_conf.h > @@ -1052,6 +1052,7 @@ struct _virDomainChrSourceDef { > /* no <source> for null, vc, stdio */ > struct { > char *path; > + int startupPolicy; /* enum virDomainStartupPolicy */ > } file; /* pty, file, pipe, or device */ > struct { > char *host; > diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c > index e75c8c9..6e2f78e 100644 > --- a/src/qemu/qemu_process.c > +++ b/src/qemu/qemu_process.c > @@ -2442,7 +2442,30 @@ qemuProcessPrepareChardevDevice(virDomainDefPtr def ATTRIBUTE_UNUSED, > virReportSystemError(errno, > _("Unable to pre-create chardev file '%s'"), > dev->source.data.file.path); > - return -1; > + if (dev->source.data.file.startupPolicy != > + VIR_DOMAIN_STARTUP_POLICY_OPTIONAL) { > + 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. > + */ > + VIR_WARN("Switch the destination to /dev/null"); > + 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; > + } > } > > VIR_FORCE_CLOSE(fd); > diff --git a/tests/virt-aa-helper-test b/tests/virt-aa-helper-test > index af91c61..7172fd6 100755 > --- a/tests/virt-aa-helper-test > +++ b/tests/virt-aa-helper-test > @@ -255,6 +255,9 @@ testme "0" "disk (empty cdrom)" "-r -u $valid_uuid" "$test_xml" > sed -e "s,###UUID###,$uuid,g" -e "s,###DISK###,$disk1,g" -e "s,</devices>,<serial type='file'><source > path='$tmpdir/serial.log'/><target port='0'/></serial></devices>,g" "$template_xml" > "$test_xml" > testme "0" "serial" "-r -u $valid_uuid" "$test_xml" > > +sed -e "s,###UUID###,$uuid,g" -e "s,###DISK###,$disk1,g" -e "s,</devices>,<serial type='file'><source path='$tmpdir/serial.log' > startupPolicy='optional'/><target port='0'/></serial></devices>,g" "$template_xml" > "$test_xml" > +testme "0" "serial" "-r -u $valid_uuid" "$test_xml" > + > sed -e "s,###UUID###,$uuid,g" -e "s,###DISK###,$disk1,g" -e "s,</devices>,<serial type='pty'><target > port='0'/></serial></devices>,g" "$template_xml" > "$test_xml" > testme "0" "serial (pty)" "-r -u $valid_uuid" "$test_xml" > > -- > 1.7.1 -- libvir-list mailing list libvir-list(a)redhat.com https://www.redhat.com/mailman/listinfo/libvir-list