On 04/22/2010 11:06 AM, Kenneth Nagin wrote:
> Support for live migration between hosts that do not share storage was
> added to qemu-kvm release 0.12.1.
> It supports two flags:
> -b migration without shared storage with full disk copy
> -i migration without shared storage with incremental copy (same base image
> shared between source and destination).
>
> In order to support kvm's live migration with non-shared storage I added
> two migration flags that user can invoke:
>
> VIR_MIGRATE_NON_SHARED_DISK = (1 << 6), /* migration with non-shared
> storage with full disk copy */
> VIR_MIGRATE_NON_SHARED_INC = (1 << 7), /* migration with non-shared
> storage with incremental copy */
> /* (same base image shared
> between source and destination) */
> Likewise I add complementary flags to virsh migrate: non_shared_disk and
> non_shared_inc
>
> As Daniel B. suggested I also added internal flags to be passed in the
> "background" parameter to the qemu monitor:
> typedef enum {
> QEMU_MONITOR_MIGRATE_BACKGROUND = 1 << 0,
> QEMU_MONITOR_MIGRATE_NON_SHARED_DISK = 1 << 1, /* migration with
> non-shared storage with full disk copy */
> QEMU_MONITOR_MIGRATE_NON_SHARED_INC = 1 << 2, /* migration with
> non-shared storage with incremental copy */
> QEMU_MONITOR_MIGRATION_FLAGS_LAST
> };
>
> I updated qemu_driver.c's doNativeMigrate and doTunnelMigrate to map the
> external flags to the internal flags.
> I updated qemu_monitor_text's qemuMonitorTextMigrate to map the internal
> flags to the qemu monitor's command line flags.
>
> Also, qemudDomainSave ends up calling qemuMonitorTextMigrate, but it didn't
> support the external flags so I assumed that it was not relevant.
>
> I tested the live migration without shared storage (both flags) for native
> and p2p with and without tunnelling. I also verified that the fix doesn't
> affect normal migration with shared storage.
>
> Here is the diff patch file from the current git:
>
> (See attached file: libvirt_migration_ns_100422.patch)
>
>
> -- Kenneth Nagin
>
Of course, I tell you to resend then forget to review. Sorry :(
Applying the patch (to last weeks checkout), there are some compiler warnings:
make sure you configure with --enable-compiler-warnings=error. 'make
syntax-check' also fails, so please address these.
Also, changes are probably needed to qemu_monitor_json.c to enable this
feature for future qemu releases. Probably a simple change, but I don't know
what it should be. Maybe Danpb can chime in here.
Finding a way to post the patch in-line will also probably get better
attention: just pasting it into the mail client will probably mangle the
patch, I'd recommend git send-email.
For the virsh changes, I wouldn't use underscores in cli flag names. Maybe
change this to 'copy-storage' and 'increment-storage'. Not too fond of the
latter, maybe others have ideas.
Other than that, the code generally looks like (except for the compiler and
syntax-check warnings).
- Cole
(Here's the patch inline for the benefit of other reviewers)
> diff --git a/include/libvirt/libvirt.h.in b/include/libvirt/libvirt.h.in
> index 4addc62..28fabd9 100644
> --- a/include/libvirt/libvirt.h.in
> +++ b/include/libvirt/libvirt.h.in
> @@ -411,6 +411,10 @@ typedef enum {
> VIR_MIGRATE_PERSIST_DEST = (1 << 3), /* persist the VM on the destination */
> VIR_MIGRATE_UNDEFINE_SOURCE = (1 << 4), /* undefine the VM on the source */
> VIR_MIGRATE_PAUSED = (1 << 5), /* pause on remote side */
> + VIR_MIGRATE_NON_SHARED_DISK = (1 << 6), /* migration with non-shared storage with full disk copy */
> + VIR_MIGRATE_NON_SHARED_INC = (1 << 7), /* migration with non-shared storage with incremental copy */
> + /* (same base image shared between source and destination) */
> +
> } virDomainMigrateFlags;
>
> /* Domain migration. */
> diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
> index 5f4adfd..521638c 100644
> --- a/src/qemu/qemu_driver.c
> +++ b/src/qemu/qemu_driver.c
> @@ -4871,7 +4871,7 @@ static int qemudDomainSaveFlag(virDomainPtr dom, const char *path,
> if (header.compressed == QEMUD_SAVE_FORMAT_RAW) {
> const char *args[] = { "cat", NULL };
> qemuDomainObjEnterMonitorWithDriver(driver, vm);
> - rc = qemuMonitorMigrateToCommand(priv->mon, 1, args, path);
> + rc = qemuMonitorMigrateToCommand(priv->mon, QEMU_MONITOR_MIGRATE_BACKGROUND, args, path);
> qemuDomainObjExitMonitorWithDriver(driver, vm);
> } else {
> const char *prog = qemudSaveCompressionTypeToString(header.compressed);
> @@ -4881,7 +4881,7 @@ static int qemudDomainSaveFlag(virDomainPtr dom, const char *path,
> NULL
> };
> qemuDomainObjEnterMonitorWithDriver(driver, vm);
> - rc = qemuMonitorMigrateToCommand(priv->mon, 1, args, path);
> + rc = qemuMonitorMigrateToCommand(priv->mon, QEMU_MONITOR_MIGRATE_BACKGROUND, args, path);
> qemuDomainObjExitMonitorWithDriver(driver, vm);
> }
>
> @@ -5173,7 +5173,7 @@ static int qemudDomainCoreDump(virDomainPtr dom,
> }
>
> qemuDomainObjEnterMonitor(vm);
> - ret = qemuMonitorMigrateToCommand(priv->mon, 1, args, path);
> + ret = qemuMonitorMigrateToCommand(priv->mon, QEMU_MONITOR_MIGRATE_BACKGROUND, args, path);
> qemuDomainObjExitMonitor(vm);
>
> if (ret < 0)
> @@ -9650,13 +9650,14 @@ cleanup:
> static int doNativeMigrate(struct qemud_driver *driver,
> virDomainObjPtr vm,
> const char *uri,
> - unsigned long flags ATTRIBUTE_UNUSED,
> + unsigned long flags ,
> const char *dname ATTRIBUTE_UNUSED,
> unsigned long resource)
> {
> int ret = -1;
> xmlURIPtr uribits = NULL;
> qemuDomainObjPrivatePtr priv = vm->privateData;
> + int background_flags = 0;
>
> /* Issue the migrate command. */
> if (STRPREFIX(uri, "tcp:") && !STRPREFIX(uri, "tcp://")) {
> @@ -9684,7 +9685,13 @@ static int doNativeMigrate(struct qemud_driver *driver,
> goto cleanup;
> }
>
> - if (qemuMonitorMigrateToHost(priv->mon, 1, uribits->server, uribits->port) < 0) {
> + if (flags & VIR_MIGRATE_NON_SHARED_DISK)
> + background_flags |= QEMU_MONITOR_MIGRATE_NON_SHARED_DISK;
> +
> + if (flags & VIR_MIGRATE_NON_SHARED_INC)
> + background_flags |= QEMU_MONITOR_MIGRATE_NON_SHARED_INC;
> +
> + if (qemuMonitorMigrateToHost(priv->mon, background_flags, uribits->server, uribits->port) < 0) {
> qemuDomainObjExitMonitorWithDriver(driver, vm);
> goto cleanup;
> }
> @@ -9769,7 +9776,7 @@ static int doTunnelMigrate(virDomainPtr dom,
> unsigned long long qemuCmdFlags;
> int status;
> unsigned long long transferred, remaining, total;
> -
> + int background_flags = QEMU_MONITOR_MIGRATE_BACKGROUND;
> /*
> * The order of operations is important here to avoid touching
> * the source VM until we are very sure we can successfully
> @@ -9854,11 +9861,16 @@ static int doTunnelMigrate(virDomainPtr dom,
>
> /* 3. start migration on source */
> qemuDomainObjEnterMonitorWithDriver(driver, vm);
> - if (qemuCmdFlags & QEMUD_CMD_FLAG_MIGRATE_QEMU_UNIX)
> - internalret = qemuMonitorMigrateToUnix(priv->mon, 1, unixfile);
> + if (flags & VIR_MIGRATE_NON_SHARED_DISK)
> + background_flags |= QEMU_MONITOR_MIGRATE_NON_SHARED_DISK;
> + if (flags & VIR_MIGRATE_NON_SHARED_INC)
> + background_flags |= QEMU_MONITOR_MIGRATE_NON_SHARED_INC;
> + if (qemuCmdFlags & QEMUD_CMD_FLAG_MIGRATE_QEMU_UNIX){
> + internalret = qemuMonitorMigrateToUnix(priv->mon, background_flags, unixfile);
> + }
> else if (qemuCmdFlags & QEMUD_CMD_FLAG_MIGRATE_QEMU_EXEC) {
> const char *args[] = { "nc", "-U", unixfile, NULL };
> - internalret = qemuMonitorMigrateToCommand(priv->mon, 1, args, "/dev/null");
> + internalret = qemuMonitorMigrateToCommand(priv->mon, background_flags, args, "/dev/null");
> } else {
> internalret = -1;
> }
> diff --git a/src/qemu/qemu_monitor.h b/src/qemu/qemu_monitor.h
> index 251233a..40a21f5 100644
> --- a/src/qemu/qemu_monitor.h
> +++ b/src/qemu/qemu_monitor.h
> @@ -239,6 +239,13 @@ int qemuMonitorGetMigrationStatus(qemuMonitorPtr mon,
> unsigned long long *remaining,
> unsigned long long *total);
>
> +typedef enum {
> + QEMU_MONITOR_MIGRATE_BACKGROUND = 1 << 0,
> + QEMU_MONITOR_MIGRATE_NON_SHARED_DISK = 1 << 1, /* migration with non-shared storage with full disk copy */
> + QEMU_MONITOR_MIGRATE_NON_SHARED_INC = 1 << 2, /* migration with non-shared storage with incremental copy */
> + QEMU_MONITOR_MIGRATION_FLAGS_LAST
> +};
> +
> int qemuMonitorMigrateToHost(qemuMonitorPtr mon,
> int background,
> const char *hostname,
> diff --git a/src/qemu/qemu_monitor_text.c b/src/qemu/qemu_monitor_text.c
> index 6ad07b1..136ac12 100644
> --- a/src/qemu/qemu_monitor_text.c
> +++ b/src/qemu/qemu_monitor_text.c
> @@ -1132,18 +1132,19 @@ static int qemuMonitorTextMigrate(qemuMonitorPtr mon,
> char *info = NULL;
> int ret = -1;
> char *safedest = qemuMonitorEscapeArg(dest);
> - const char *extra;
> + //const char *extra;
> + const char extra[25] = " ";
>
> if (!safedest) {
> virReportOOMError();
> return -1;
> }
> -
> - if (background)
> - extra = "-d ";
> - else
> - extra = " ";
> -
> + if (background & QEMU_MONITOR_MIGRATE_BACKGROUND)
> + strcat(extra," -d");
> + if (background & QEMU_MONITOR_MIGRATE_NON_SHARED_DISK)
> + strcat(extra," -b");
> + if (background & QEMU_MONITOR_MIGRATE_NON_SHARED_INC)
> + strcat(extra," -i");
> if (virAsprintf(&cmd, "migrate %s\"%s\"", extra, safedest) < 0) {
> virReportOOMError();
> goto cleanup;
> diff --git a/tools/virsh.c b/tools/virsh.c
> index b2a1538..bd8719e 100644
> --- a/tools/virsh.c
> +++ b/tools/virsh.c
> @@ -2804,6 +2804,8 @@ static const vshCmdOptDef opts_migrate[] = {
> {"persistent", VSH_OT_BOOL, 0, N_("persist VM on destination")},
> {"undefinesource", VSH_OT_BOOL, 0, N_("undefine VM on source")},
> {"suspend", VSH_OT_BOOL, 0, N_("do not restart the domain on the destination host")},
> + {"non_shared_disk", VSH_OT_BOOL, 0, N_("migration with non-shared storage with full disk copy")},
> + {"non_shared_inc", VSH_OT_BOOL, 0, N_("migration with non-shared storage with incremental copy (same base image shared between source and destination)")},
> {"domain", VSH_OT_DATA, VSH_OFLAG_REQ, N_("domain name, id or uuid")},
> {"desturi", VSH_OT_DATA, VSH_OFLAG_REQ, N_("connection URI of the destination host")},
> {"migrateuri", VSH_OT_DATA, 0, N_("migration URI, usually can be omitted")},
> @@ -2851,6 +2853,12 @@ cmdMigrate (vshControl *ctl, const vshCmd *cmd)
> if (vshCommandOptBool (cmd, "suspend"))
> flags |= VIR_MIGRATE_PAUSED;
>
> + if (vshCommandOptBool (cmd, "non_shared_disk"))
> + flags |= VIR_MIGRATE_NON_SHARED_DISK;
> +
> + if (vshCommandOptBool (cmd, "non_shared_inc"))
> + flags |= VIR_MIGRATE_NON_SHARED_INC;
> +
> if ((flags & VIR_MIGRATE_PEER2PEER) ||
> vshCommandOptBool (cmd, "direct")) {
> /* For peer2peer migration or direct migration we only expect one URI
--
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