[libvirt] [RFC PATCHv2 1/3] qemu: use lighter-weight fd:n on incoming tunneled migration
Outgoing migration still uses a Unix socket and or exec netcat until
the next patch.
* src/qemu/qemu_migration.c (qemuMigrationPrepareTunnel):
Replace Unix socket with simpler pipe.
Suggested by Paolo Bonzini.
---
v1 was ack'd here but not yet applied:
https://www.redhat.com/archives/libvir-list/2011-January/msg00742.html
changes in v2: rebase to latest upstream
src/qemu/qemu_migration.c | 44 ++++++++++++--------------------------------
1 files changed, 12 insertions(+), 32 deletions(-)
diff --git a/src/qemu/qemu_migration.c b/src/qemu/qemu_migration.c
index 822cb18..dc51bc8 100644
--- a/src/qemu/qemu_migration.c
+++ b/src/qemu/qemu_migration.c
@@ -239,11 +239,10 @@ qemuMigrationPrepareTunnel(struct qemud_driver *driver,
{
virDomainDefPtr def = NULL;
virDomainObjPtr vm = NULL;
- char *migrateFrom;
virDomainEventPtr event = NULL;
int ret = -1;
int internalret;
- char *unixfile = NULL;
+ int dataFD[2] = { -1, -1 };
virBitmapPtr qemuCaps = NULL;
qemuDomainObjPrivatePtr priv = NULL;
struct timeval now;
@@ -289,12 +288,11 @@ qemuMigrationPrepareTunnel(struct qemud_driver *driver,
/* Domain starts inactive, even if the domain XML had an id field. */
vm->def->id = -1;
- if (virAsprintf(&unixfile, "%s/qemu.tunnelmigrate.dest.%s",
- driver->libDir, vm->def->name) < 0) {
- virReportOOMError();
+ if (pipe(dataFD) < 0) {
+ virReportSystemError(errno, "%s",
+ _("cannot create pipe for tunnelled migration"));
goto endjob;
}
- unlink(unixfile);
/* check that this qemu version supports the interactive exec */
if (qemuCapsExtractVersionInfo(vm->def->emulator, vm->def->os.arch,
@@ -304,25 +302,11 @@ qemuMigrationPrepareTunnel(struct qemud_driver *driver,
vm->def->emulator);
goto endjob;
}
- if (qemuCapsGet(qemuCaps, QEMU_CAPS_MIGRATE_QEMU_UNIX))
- internalret = virAsprintf(&migrateFrom, "unix:%s", unixfile);
- else if (qemuCapsGet(qemuCaps, QEMU_CAPS_MIGRATE_QEMU_EXEC))
- internalret = virAsprintf(&migrateFrom, "exec:nc -U -l %s",
unixfile);
- else {
- qemuReportError(VIR_ERR_OPERATION_FAILED,
- "%s", _("Destination qemu is too old to support
tunnelled migration"));
- goto endjob;
- }
- if (internalret < 0) {
- virReportOOMError();
- goto endjob;
- }
/* Start the QEMU daemon, with the same command-line arguments plus
- * -incoming unix:/path/to/file or exec:nc -U /path/to/file
+ * -incoming stdin (which qemu_command might convert to exec:cat or fd:n)
*/
- internalret = qemuProcessStart(dconn, driver, vm, migrateFrom, true,
- -1, NULL, VIR_VM_OP_MIGRATE_IN_START);
- VIR_FREE(migrateFrom);
+ internalret = qemuProcessStart(dconn, driver, vm, "stdin", true,
dataFD[1],
+ NULL, VIR_VM_OP_MIGRATE_IN_START);
if (internalret < 0) {
qemuDomainStartAudit(vm, "migrated", false);
/* Note that we don't set an error here because qemuProcessStart
@@ -335,9 +319,7 @@ qemuMigrationPrepareTunnel(struct qemud_driver *driver,
goto endjob;
}
- if (virFDStreamConnectUNIX(st,
- unixfile,
- false) < 0) {
+ if (virFDStreamOpen(st, dataFD[0]) < 0) {
qemuDomainStartAudit(vm, "migrated", false);
qemuProcessStop(driver, vm, 0);
if (!vm->persistent) {
@@ -345,9 +327,8 @@ qemuMigrationPrepareTunnel(struct qemud_driver *driver,
virDomainRemoveInactive(&driver->domains, vm);
vm = NULL;
}
- virReportSystemError(errno,
- _("cannot open unix socket '%s' for tunnelled
migration"),
- unixfile);
+ virReportSystemError(errno, "%s",
+ _("cannot pass pipe for tunnelled migration"));
goto endjob;
}
@@ -378,9 +359,8 @@ endjob:
cleanup:
qemuCapsFree(qemuCaps);
virDomainDefFree(def);
- if (unixfile)
- unlink(unixfile);
- VIR_FREE(unixfile);
+ VIR_FORCE_CLOSE(dataFD[0]);
+ VIR_FORCE_CLOSE(dataFD[1]);
if (vm)
virDomainObjUnlock(vm);
if (event)
--
1.7.4