On Tue, Sep 08, 2015 at 09:26:11AM +0100, Joao Martins wrote:
> Introduce support for VIR_MIGRATE_PEER2PEER in libvirt migration.
> Most of the changes occur at the source and no modifications
> at the receiver.
>
> In P2P mode there is only the Perform phase so we must handle
> the connection with the destination and actually perform the
> migration. libxlDomainPerformP2P implements the connection to
> the destination and let libxlDoMigrateP2P implements the actual
> migration logic with virConnectPtr. In this function we take
> of doing all phases of migration in the destination similar to
> virDomainMigrateVersion3Full. We appropriately save the last
> error reported in each of the phases to provide proper
> reporting. We don't yet support VIR_MIGRATE_TUNNELED yet and
> we always use V3 with extensible params, thus it also makes the
> implementation simpler.
>
> It is worth noting that the receiver didn't have any changes,
> and since it's still the v3 sequence thus it is possible to
> migrate from a P2P to non-P2P host.
>
> Signed-off-by: Joao Martins <joao.m.martins@xxxxxxxxxx>
> ---
> src/libxl/libxl_driver.c | 13 ++-
> src/libxl/libxl_migration.c | 220 ++++++++++++++++++++++++++++++++++++++++++++
> src/libxl/libxl_migration.h | 11 +++
> 3 files changed, 241 insertions(+), 3 deletions(-)
>
> diff --git a/src/libxl/libxl_driver.c b/src/libxl/libxl_driver.c
> index 5f69b49..4d6821f 100644
> --- a/src/libxl/libxl_driver.c
> +++ b/src/libxl/libxl_driver.c
> @@ -4710,6 +4710,7 @@ libxlConnectSupportsFeature(virConnectPtr conn, int feature)
> switch (feature) {
> case VIR_DRV_FEATURE_TYPED_PARAM_STRING:
> case VIR_DRV_FEATURE_MIGRATION_PARAMS:
> + case VIR_DRV_FEATURE_MIGRATION_P2P:
> return 1;
> default:
> return 0;
> @@ -5036,9 +5037,15 @@ libxlDomainMigratePerform3Params(virDomainPtr dom,
> if (virDomainMigratePerform3ParamsEnsureACL(dom->conn, vm->def) < 0)
> goto cleanup;
>
> - if (libxlDomainMigrationPerform(driver, vm, dom_xml, dconnuri,
> - uri, dname, flags) < 0)
> - goto cleanup;
> + if (flags & VIR_MIGRATE_PEER2PEER) {
> + if (libxlDomainMigrationPerformP2P(driver, vm, dom->conn, dom_xml,
> + dconnuri, uri, dname, flags) < 0)
> + goto cleanup;
> + } else {
> + if (libxlDomainMigrationPerform(driver, vm, dom_xml, dconnuri,
> + uri, dname, flags) < 0)
> + goto cleanup;
> + }
>
> ret = 0;
>
> diff --git a/src/libxl/libxl_migration.c b/src/libxl/libxl_migration.c
> index 0d23e5f..659f4d8 100644
> --- a/src/libxl/libxl_migration.c
> +++ b/src/libxl/libxl_migration.c
> @@ -42,6 +42,7 @@
> #include "libxl_conf.h"
> #include "libxl_migration.h"
> #include "locking/domain_lock.h"
> +#include "virtypedparam.h"
>
> #define VIR_FROM_THIS VIR_FROM_LIBXL
>
> @@ -456,6 +457,225 @@ libxlDomainMigrationPrepare(virConnectPtr dconn,
> return ret;
> }
>
> +/* This function is a simplification of virDomainMigrateVersion3Full
> + * excluding tunnel support and restricting it to migration v3
> + * with params since it was the first to be introduced in libxl.
> + */
> +static int
> +libxlDoMigrateP2P(libxlDriverPrivatePtr driver,
> + virDomainObjPtr vm,
> + const char *dom_xml,
> + virConnectPtr dconn,
> + const char *dconnuri ATTRIBUTE_UNUSED,
> + const char *dname,
> + const char *uri,
> + unsigned int flags)
> +{
> + virDomainPtr ddomain = NULL;
> + virTypedParameterPtr params = NULL;
> + int nparams = 0;
> + int maxparams = 0;
> + char *uri_out = NULL;
> + unsigned long destflags;
> + bool cancelled = true;
> + virErrorPtr orig_err = NULL;
> + int ret = -1;
> +
> + if (virTypedParamsAddString(¶ms, &nparams, &maxparams,
> + VIR_MIGRATE_PARAM_DEST_XML, dom_xml) < 0)
> + goto cleanup;
> +
> + if (dname &&
> + virTypedParamsAddString(¶ms, &nparams, &maxparams,
> + VIR_MIGRATE_PARAM_DEST_NAME, dname) < 0)
> + goto cleanup;
> +
> + if (uri &&
> + virTypedParamsAddString(¶ms, &nparams, &maxparams,
> + VIR_MIGRATE_PARAM_URI, uri) < 0)
> + goto cleanup;
> +
> + /* We don't require the destination to have P2P support
> + * as it looks to be normal migration from the receiver perpective.
> + */
> + destflags = flags & ~(VIR_MIGRATE_PEER2PEER);
> +
> + VIR_DEBUG("Prepare3");
> + virObjectUnlock(vm);
> + ret = dconn->driver->domainMigratePrepare3Params
> + (dconn, params, nparams, NULL, 0, NULL, NULL, &uri_out, destflags);
> + virObjectLock(vm);
> +
> + if (ret == -1)
> + goto cleanup;
> +
> + if (uri_out) {
> + if (virTypedParamsReplaceString(¶ms, &nparams,
> + VIR_MIGRATE_PARAM_URI, uri_out) < 0) {
> + orig_err = virSaveLastError();
> + goto finish;
> + }
> + } else {
> + virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
> + _("domainMigratePrepare3 did not set uri"));
> + goto finish;
> + }
> +
> + VIR_DEBUG("Perform3 uri=%s", NULLSTR(uri_out));
> + ret = libxlDomainMigrationPerform(driver, vm, NULL, NULL,
> + uri_out, NULL, flags);
> +
> + if (ret < 0)
> + orig_err = virSaveLastError();
> +
> + cancelled = (ret < 0);
> +
> + finish:
> + VIR_DEBUG("Finish3 ret=%d", ret);
> + if (virTypedParamsGetString(params, nparams,
> + VIR_MIGRATE_PARAM_DEST_NAME, NULL) <= 0 &&
> + virTypedParamsReplaceString(¶ms, &nparams,
> + VIR_MIGRATE_PARAM_DEST_NAME,
> + vm->def->name) < 0) {
> + ddomain = NULL;
> + } else {
> + virObjectUnlock(vm);
> + ddomain = dconn->driver->domainMigrateFinish3Params
> + (dconn, params, nparams, NULL, 0, NULL, NULL,
> + destflags, cancelled);
> + virObjectLock(vm);
> + }
> +
> + cancelled = (ddomain == NULL);
> +
> + /* If Finish3Params set an error, and we don't have an earlier
> + * one we need to preserve it in case confirm3 overwrites
> + */
> + if (!orig_err)
> + orig_err = virSaveLastError();
> +
> + VIR_DEBUG("Confirm3 cancelled=%d vm=%p", cancelled, vm);
> + ret = libxlDomainMigrationConfirm(driver, vm, flags, cancelled);
> +
> + if (ret < 0)
> + VIR_WARN("Guest %s probably left in 'paused' state on source",
> + vm->def->name);
> +
> + cleanup:
> + if (ddomain) {
> + virObjectUnref(ddomain);
> + ret = 0;
> + } else {
> + ret = -1;
> + }
> +
> + if (orig_err) {
> + virSetError(orig_err);
> + virFreeError(orig_err);
> + }
> +
> + VIR_FREE(uri_out);
> + virTypedParamsFree(params, nparams);
> + return ret;
> +}
> +
> +static int virConnectCredType[] = {
> + VIR_CRED_AUTHNAME,
> + VIR_CRED_PASSPHRASE,
> +};
> +
> +
> +static virConnectAuth virConnectAuthConfig = {
> + .credtype = virConnectCredType,
> + .ncredtype = ARRAY_CARDINALITY(virConnectCredType),
> +};
> +
> +static void
> +libxlMigrationConnectionClosed(virConnectPtr conn,
> + int reason,
> + void *opaque)
> +{
> + virDomainObjPtr vm = opaque;
> +
> + VIR_DEBUG("conn=%p, reason=%d, vm=%s", conn, reason, vm->def->name);
> + virDomainObjBroadcast(vm);
> +}
> +
> +/* On P2P mode there is only the Perform3 phase and we need to handle
> + * the connection with the destination libvirtd and perform the migration.
> + * Here we first tackle the first part of it, and libxlDoMigrationP2P handles
> + * the migration process with an established virConnectPtr to the destination.
> + */
> +int
> +libxlDomainMigrationPerformP2P(libxlDriverPrivatePtr driver,
> + virDomainObjPtr vm,
> + virConnectPtr sconn,
> + const char *xmlin,
> + const char *dconnuri,
> + const char *uri_str ATTRIBUTE_UNUSED,
> + const char *dname,
> + unsigned int flags)
> +{
> + char *dom_xml;
> + int ret = -1;
> + int keepAliveInterval = 5;
> + int keepAliveCount = 5;
> + bool useParams;
> + virConnectPtr dconn = NULL;
> + virErrorPtr orig_err = NULL;
> +
> + virObjectUnlock(vm);
> + dconn = virConnectOpenAuth(dconnuri, &virConnectAuthConfig, 0);
> + virObjectLock(vm);
> +
> + if (dconn == NULL) {
> + virReportError(VIR_ERR_OPERATION_FAILED,
> + _("Failed to connect to remote libvirt URI %s: %s"),
> + dconnuri, virGetLastErrorMessage());
> + return ret;
> + }
> +
> + if (virConnectSetKeepAlive(dconn, keepAliveInterval,
> + keepAliveCount) < 0)
> + goto cleanup;
> +
> + if (virConnectRegisterCloseCallback(dconn, libxlMigrationConnectionClosed,
> + vm, NULL) < 0) {
> + goto cleanup;
> + }
> +
> + virObjectUnlock(vm);
> + useParams = VIR_DRV_SUPPORTS_FEATURE(dconn->driver, dconn,
> + VIR_DRV_FEATURE_MIGRATION_PARAMS);
> + virObjectLock(vm);
> +
> + if (!useParams) {
> + virReportError(VIR_ERR_OPERATION_FAILED, "%s",
> + _("Destination libvirt does not support migration with extensible parameters"));
> + goto cleanup;
> + }
> +
> + dom_xml = libxlDomainMigrationBegin(sconn, vm, xmlin);
> + if (!dom_xml)
> + goto cleanup;
Since you have the other 4 steps of the V3 protocol invoked
in libxlDoMigrateP2P, I'd rather expect the Begin step to
be in that method too.
> +
> + ret = libxlDoMigrateP2P(driver, vm, dom_xml, dconn, dconnuri,
> + dname, uri_str, flags);
> +
> + VIR_FREE(dom_xml);
> + cleanup:
> + orig_err = virSaveLastError();
> + virObjectUnlock(vm);
> + virConnectUnregisterCloseCallback(dconn, libxlMigrationConnectionClosed);
> + virObjectUnref(dconn);
> + virObjectLock(vm);
> + if (orig_err) {
> + virSetError(orig_err);
> + virFreeError(orig_err);
> + }
> + return ret;
> +}
Regards,
Daniel
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