On 12/03/2015 12:18 PM, Joao Martins wrote:
On 12/02/2015 11:27 PM, Jim Fehlig wrote:
Introduce support for VIR_MIGRATE_PEER2PEER in libxl driver for supporting migration in Openstack. 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 do the migration steps 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 and we always use V3 with extensible params, making the implementation simpler.
It is worth noting that the receiver didn't have any changes, and because 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@oracle.com> --- Changes since v1: - Move Begin step to libxlDoMigrateP2P to have all 4 steps together. - Remove if before VIR_FREE(dom_xml) --- 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 fcdcbdb..da98265 100644 --- a/src/libxl/libxl_driver.c +++ b/src/libxl/libxl_driver.c @@ -4713,6 +4713,7 @@ 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; @@ -5039,9 +5040,15 @@ 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..a1c7b55 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, + virConnectPtr sconn, + const char *xmlin, + 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; + char *dom_xml = NULL; + unsigned long destflags; + bool cancelled = true; + virErrorPtr orig_err = NULL; + int ret = -1; + + dom_xml = libxlDomainMigrationBegin(sconn, vm, xmlin); + if (!dom_xml) + goto cleanup; + + 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); Is it necessary to unlock and lock the vm while calling prepare and finish on
On 11/10/2015 08:32 AM, Joao Martins wrote: the destination libvirtd?
They can be removed, but then we leave the virDomainObj locked for a "long" time when no operations are being done on his context. Plus no API calls could be done there in the meantime (and migration can take a rather long time).
Ah, right. Dropping the lock is fine, but IMO we'll need a modify job to protect the domain from modification by another thread. I think the existing migration code needs improvement wrt job handling too :-/. Regards, Jim