I wonder if there's a reason why it is not possible to dump the core of a KVM domain which is set to autodestroy. $ virsh dump guestfs-4xe592eyqq4rfnk9 /tmp/guestfs-4xe592eyqq4rfnk9.core error: Failed to core dump domain guestfs-4xe592eyqq4rfnk9 to /tmp/guestfs-4xe592eyqq4rfnk9.core error: Requested operation is not valid: domain is marked for auto destroy All libguestfs domains have the autodestroy flag, but I am trying to debug one which is crashing in the guest (RHBZ#1269779) and having the ability to dump it would be very helpful. I added the following patch to libvirt, which allowed me to dump the domain with no apparent ill effects. (The patch is a bit of a hack, and I did not check it very closely, so it's probably not suitable for going upstream). Rich.

From ffb899e436c15974b0f42b1cbd8337701c3a05d1 Mon Sep 17 00:00:00 2001 From: "Richard W.M. Jones" <rjones@redhat.com> Date: Thu, 8 Oct 2015 11:11:10 +0100 Subject: [PATCH] qemu: Don't prevent core dump of auto-destroy domain.

--- src/qemu/qemu_driver.c | 8 ++++---- src/qemu/qemu_migration.c | 16 +++++++++------- src/qemu/qemu_migration.h | 2 +- 3 files changed, 14 insertions(+), 12 deletions(-) diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c index 8cd5ee3..c3778de 100644 --- a/src/qemu/qemu_driver.c +++ b/src/qemu/qemu_driver.c @@ -3184,7 +3184,7 @@ qemuDomainSaveInternal(virQEMUDriverPtr driver, virDomainPtr dom, if (!(caps = virQEMUDriverGetCapabilities(driver, false))) goto cleanup; - if (!qemuMigrationIsAllowed(driver, vm, false, 0)) + if (!qemuMigrationIsAllowed(driver, vm, false, false, 0)) goto cleanup; if (qemuDomainObjBeginAsyncJob(driver, vm, QEMU_ASYNC_JOB_SAVE) < 0) @@ -3616,7 +3616,7 @@ doCoreDump(virQEMUDriverPtr driver, goto cleanup; } - if (!qemuMigrationIsAllowed(driver, vm, false, 0)) + if (!qemuMigrationIsAllowed(driver, vm, false, true, 0)) goto cleanup; ret = qemuMigrationToFile(driver, vm, fd, 0, path, @@ -13690,7 +13690,7 @@ qemuDomainSnapshotCreateActiveInternal(virConnectPtr conn, bool resume = false; int ret = -1; - if (!qemuMigrationIsAllowed(driver, vm, false, 0)) + if (!qemuMigrationIsAllowed(driver, vm, false, false, 0)) goto cleanup; if (virDomainObjGetState(vm, NULL) == VIR_DOMAIN_RUNNING) { @@ -14505,7 +14505,7 @@ qemuDomainSnapshotCreateActiveExternal(virConnectPtr conn, /* do the memory snapshot if necessary */ if (memory) { /* check if migration is possible */ - if (!qemuMigrationIsAllowed(driver, vm, false, 0)) + if (!qemuMigrationIsAllowed(driver, vm, false, false, 0)) goto cleanup; /* allow the migration job to be cancelled or the domain to be paused */ diff --git a/src/qemu/qemu_migration.c b/src/qemu/qemu_migration.c index d0f1e46..19031f9 100644 --- a/src/qemu/qemu_migration.c +++ b/src/qemu/qemu_migration.c @@ -2201,7 +2201,7 @@ qemuMigrationIsAllowedHostdev(const virDomainDef *def) bool qemuMigrationIsAllowed(virQEMUDriverPtr driver, virDomainObjPtr vm, - bool remote, + bool remote, bool coreDump, unsigned int flags) { int nsnapshots; @@ -2235,10 +2235,12 @@ qemuMigrationIsAllowed(virQEMUDriverPtr driver, /* following checks don't make sense for offline migration */ if (!(flags & VIR_MIGRATE_OFFLINE)) { - if (qemuProcessAutoDestroyActive(driver, vm)) { - virReportError(VIR_ERR_OPERATION_INVALID, - "%s", _("domain is marked for auto destroy")); - return false; + if (!coreDump) { + if (qemuProcessAutoDestroyActive(driver, vm)) { + virReportError(VIR_ERR_OPERATION_INVALID, + "%s", _("domain is marked for auto destroy")); + return false; + } } @@ -2987,7 +2989,7 @@ qemuMigrationBeginPhase(virQEMUDriverPtr driver, if (priv->job.asyncJob == QEMU_ASYNC_JOB_MIGRATION_OUT) qemuMigrationJobSetPhase(driver, vm, QEMU_MIGRATION_PHASE_BEGIN3); - if (!qemuMigrationIsAllowed(driver, vm, true, flags)) + if (!qemuMigrationIsAllowed(driver, vm, true, false, flags)) goto cleanup; if (!(flags & VIR_MIGRATE_UNSAFE) && @@ -5347,7 +5349,7 @@ qemuMigrationPerformJob(virQEMUDriverPtr driver, goto endjob; } - if (!qemuMigrationIsAllowed(driver, vm, true, flags)) + if (!qemuMigrationIsAllowed(driver, vm, true, false, flags)) goto endjob; if (!(flags & VIR_MIGRATE_UNSAFE) && diff --git a/src/qemu/qemu_migration.h b/src/qemu/qemu_migration.h index 8175f4b..cc4d25d 100644 --- a/src/qemu/qemu_migration.h +++ b/src/qemu/qemu_migration.h @@ -174,7 +174,7 @@ int qemuMigrationConfirm(virConnectPtr conn, int cancelled); bool qemuMigrationIsAllowed(virQEMUDriverPtr driver, virDomainObjPtr vm, - bool remote, unsigned int flags); + bool remote, bool coreDump, unsigned int flags); int qemuMigrationToFile(virQEMUDriverPtr driver, virDomainObjPtr vm, int fd, off_t offset, const char *path, -- 2.5.3 -- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones Read my programming and virtualization blog: http://rwmj.wordpress.com virt-p2v converts physical machines to virtual machines. Boot with a live CD or over the network (PXE) and turn machines into KVM guests. http://libguestfs.org/virt-v2v