[libvirt] [PATCH V4] libxl: add migration support

This patch adds initial migration support to the libxl driver, using the VIR_DRV_FEATURE_MIGRATION_PARAMS family of migration functions. Signed-off-by: Jim Fehlig <jfehlig@suse.com> --- V3 here https://www.redhat.com/archives/libvir-list/2014-April/msg00968.html In V4: - Code cleanup - Improved error handling Although this patch has been floating around for a long time, not sure if it is 1.2.4 material since it brings a new feature to the libxl driver. po/POTFILES.in | 1 + src/Makefile.am | 3 +- src/libxl/libxl_conf.h | 6 + src/libxl/libxl_domain.h | 1 + src/libxl/libxl_driver.c | 224 ++++++++++ src/libxl/libxl_migration.c | 978 ++++++++++++++++++++++++++++++++++++++++++++ src/libxl/libxl_migration.h | 78 ++++ 7 files changed, 1290 insertions(+), 1 deletion(-) diff --git a/po/POTFILES.in b/po/POTFILES.in index e35eb82..a72dc1e 100644 --- a/po/POTFILES.in +++ b/po/POTFILES.in @@ -73,6 +73,7 @@ src/lxc/lxc_process.c src/libxl/libxl_domain.c src/libxl/libxl_driver.c src/libxl/libxl_conf.c +src/libxl/libxl_migration.c src/network/bridge_driver.c src/network/bridge_driver_linux.c src/node_device/node_device_driver.c diff --git a/src/Makefile.am b/src/Makefile.am index e9dc9e0..0dbda7f 100644 --- a/src/Makefile.am +++ b/src/Makefile.am @@ -706,7 +706,8 @@ XENAPI_DRIVER_SOURCES = \ LIBXL_DRIVER_SOURCES = \ libxl/libxl_conf.c libxl/libxl_conf.h \ libxl/libxl_domain.c libxl/libxl_domain.h \ - libxl/libxl_driver.c libxl/libxl_driver.h + libxl/libxl_driver.c libxl/libxl_driver.h \ + libxl/libxl_migration.c libxl/libxl_migration.h UML_DRIVER_SOURCES = \ uml/uml_conf.c uml/uml_conf.h \ diff --git a/src/libxl/libxl_conf.h b/src/libxl/libxl_conf.h index 24e1720..b798567 100644 --- a/src/libxl/libxl_conf.h +++ b/src/libxl/libxl_conf.h @@ -43,6 +43,9 @@ # define LIBXL_VNC_PORT_MIN 5900 # define LIBXL_VNC_PORT_MAX 65535 +# define LIBXL_MIGRATION_PORT_MIN 49152 +# define LIBXL_MIGRATION_PORT_MAX 49216 + # define LIBXL_CONFIG_DIR SYSCONFDIR "/libvirt/libxl" # define LIBXL_AUTOSTART_DIR LIBXL_CONFIG_DIR "/autostart" # define LIBXL_STATE_DIR LOCALSTATEDIR "/run/libvirt/libxl" @@ -115,6 +118,9 @@ struct _libxlDriverPrivate { /* Immutable pointer, self-locking APIs */ virPortAllocatorPtr reservedVNCPorts; + /* Immutable pointer, self-locking APIs */ + virPortAllocatorPtr migrationPorts; + /* Immutable pointer, lockless APIs*/ virSysinfoDefPtr hostsysinfo; }; diff --git a/src/libxl/libxl_domain.h b/src/libxl/libxl_domain.h index 979ce2a..9d48049 100644 --- a/src/libxl/libxl_domain.h +++ b/src/libxl/libxl_domain.h @@ -69,6 +69,7 @@ struct _libxlDomainObjPrivate { virChrdevsPtr devs; libxl_evgen_domain_death *deathW; libxlDriverPrivatePtr driver; + unsigned short migrationPort; struct libxlDomainJobObj job; }; diff --git a/src/libxl/libxl_driver.c b/src/libxl/libxl_driver.c index e5ed0f2..2359f71 100644 --- a/src/libxl/libxl_driver.c +++ b/src/libxl/libxl_driver.c @@ -45,6 +45,7 @@ #include "libxl_domain.h" #include "libxl_driver.h" #include "libxl_conf.h" +#include "libxl_migration.h" #include "xen_xm.h" #include "xen_sxpr.h" #include "virtypedparam.h" @@ -209,6 +210,7 @@ libxlStateCleanup(void) virObjectUnref(libxl_driver->xmlopt); virObjectUnref(libxl_driver->domains); virObjectUnref(libxl_driver->reservedVNCPorts); + virObjectUnref(libxl_driver->migrationPorts); virObjectEventStateFree(libxl_driver->domainEventState); virSysinfoDefFree(libxl_driver->hostsysinfo); @@ -296,6 +298,13 @@ libxlStateInitialize(bool privileged, LIBXL_VNC_PORT_MAX))) goto error; + /* Allocate bitmap for migration port reservation */ + if (!(libxl_driver->migrationPorts = + virPortAllocatorNew(_("migration"), + LIBXL_MIGRATION_PORT_MIN, + LIBXL_MIGRATION_PORT_MAX))) + goto error; + if (!(libxl_driver->domains = virDomainObjListNew())) goto error; @@ -4126,6 +4135,7 @@ libxlConnectSupportsFeature(virConnectPtr conn, int feature) switch (feature) { case VIR_DRV_FEATURE_TYPED_PARAM_STRING: + case VIR_DRV_FEATURE_MIGRATION_PARAMS: return 1; default: return 0; @@ -4304,6 +4314,215 @@ libxlNodeDeviceReset(virNodeDevicePtr dev) return ret; } +static char * +libxlDomainMigrateBegin3Params(virDomainPtr domain, + virTypedParameterPtr params, + int nparams, + char **cookieout ATTRIBUTE_UNUSED, + int *cookieoutlen ATTRIBUTE_UNUSED, + unsigned int flags) +{ + const char *xmlin = NULL; + virDomainObjPtr vm = NULL; + + virCheckFlags(LIBXL_MIGRATION_FLAGS, NULL); + if (virTypedParamsValidate(params, nparams, LIBXL_MIGRATION_PARAMETERS) < 0) + return NULL; + + if (virTypedParamsGetString(params, nparams, + VIR_MIGRATE_PARAM_DEST_XML, + &xmlin) < 0) + return NULL; + + if (!(vm = libxlDomObjFromDomain(domain))) + return NULL; + + if (virDomainMigrateBegin3ParamsEnsureACL(domain->conn, vm->def) < 0) { + virObjectUnlock(vm); + return NULL; + } + + if (!virDomainObjIsActive(vm)) { + virReportError(VIR_ERR_OPERATION_INVALID, + "%s", _("domain is not running")); + virObjectUnlock(vm); + return NULL; + } + + return libxlDomainMigrationBegin(domain->conn, vm, xmlin); +} + +static int +libxlDomainMigratePrepare3Params(virConnectPtr dconn, + virTypedParameterPtr params, + int nparams, + const char *cookiein ATTRIBUTE_UNUSED, + int cookieinlen ATTRIBUTE_UNUSED, + char **cookieout ATTRIBUTE_UNUSED, + int *cookieoutlen ATTRIBUTE_UNUSED, + char **uri_out, + unsigned int flags) +{ + libxlDriverPrivatePtr driver = dconn->privateData; + virDomainDefPtr def = NULL; + const char *dom_xml = NULL; + const char *dname = NULL; + const char *uri_in = NULL; + + virCheckFlags(LIBXL_MIGRATION_FLAGS, -1); + if (virTypedParamsValidate(params, nparams, LIBXL_MIGRATION_PARAMETERS) < 0) + goto error; + + if (virTypedParamsGetString(params, nparams, + VIR_MIGRATE_PARAM_DEST_XML, + &dom_xml) < 0 || + virTypedParamsGetString(params, nparams, + VIR_MIGRATE_PARAM_DEST_NAME, + &dname) < 0 || + virTypedParamsGetString(params, nparams, + VIR_MIGRATE_PARAM_URI, + &uri_in) < 0) + + goto error; + + if (!(def = libxlDomainMigrationPrepareDef(driver, dom_xml, dname))) + goto error; + + if (virDomainMigratePrepare3ParamsEnsureACL(dconn, def) < 0) + goto error; + + if (libxlDomainMigrationPrepare(dconn, def, uri_in, uri_out) < 0) + goto error; + + return 0; + + error: + virDomainDefFree(def); + return -1; +} + +static int +libxlDomainMigratePerform3Params(virDomainPtr dom, + const char *dconnuri, + virTypedParameterPtr params, + int nparams, + const char *cookiein ATTRIBUTE_UNUSED, + int cookieinlen ATTRIBUTE_UNUSED, + char **cookieout ATTRIBUTE_UNUSED, + int *cookieoutlen ATTRIBUTE_UNUSED, + unsigned int flags) +{ + libxlDriverPrivatePtr driver = dom->conn->privateData; + virDomainObjPtr vm = NULL; + const char *dom_xml = NULL; + const char *dname = NULL; + const char *uri = NULL; + int ret = -1; + + virCheckFlags(LIBXL_MIGRATION_FLAGS, -1); + if (virTypedParamsValidate(params, nparams, LIBXL_MIGRATION_PARAMETERS) < 0) + goto cleanup; + + if (virTypedParamsGetString(params, nparams, + VIR_MIGRATE_PARAM_DEST_XML, + &dom_xml) < 0 || + virTypedParamsGetString(params, nparams, + VIR_MIGRATE_PARAM_DEST_NAME, + &dname) < 0 || + virTypedParamsGetString(params, nparams, + VIR_MIGRATE_PARAM_URI, + &uri) < 0) + + goto cleanup; + + if (!(vm = libxlDomObjFromDomain(dom))) + goto cleanup; + + if (virDomainMigratePerform3ParamsEnsureACL(dom->conn, vm->def) < 0) + goto cleanup; + + if (libxlDomainMigrationPerform(driver, vm, dom_xml, dconnuri, + uri, dname, flags) < 0) { + /* Job terminated and vm unlocked if MigrationPerform failed */ + vm = NULL; + goto cleanup; + } + + ret = 0; + + cleanup: + if (vm) + virObjectUnlock(vm); + return ret; +} + +static virDomainPtr +libxlDomainMigrateFinish3Params(virConnectPtr dconn, + virTypedParameterPtr params, + int nparams, + const char *cookiein ATTRIBUTE_UNUSED, + int cookieinlen ATTRIBUTE_UNUSED, + char **cookieout ATTRIBUTE_UNUSED, + int *cookieoutlen ATTRIBUTE_UNUSED, + unsigned int flags, + int cancelled) +{ + libxlDriverPrivatePtr driver = dconn->privateData; + virDomainObjPtr vm = NULL; + const char *dname = NULL; + + virCheckFlags(LIBXL_MIGRATION_FLAGS, NULL); + if (virTypedParamsValidate(params, nparams, LIBXL_MIGRATION_PARAMETERS) < 0) + return NULL; + + if (virTypedParamsGetString(params, nparams, + VIR_MIGRATE_PARAM_DEST_NAME, + &dname) < 0) + return NULL; + + if (!dname || + !(vm = virDomainObjListFindByName(driver->domains, dname))) { + virReportError(VIR_ERR_NO_DOMAIN, + _("no domain with matching name '%s'"), + NULLSTR(dname)); + return NULL; + } + + if (virDomainMigrateFinish3ParamsEnsureACL(dconn, vm->def) < 0) { + virObjectUnlock(vm); + return NULL; + } + + return libxlDomainMigrationFinish(dconn, vm, flags, cancelled); +} + +static int +libxlDomainMigrateConfirm3Params(virDomainPtr domain, + virTypedParameterPtr params, + int nparams, + const char *cookiein ATTRIBUTE_UNUSED, + int cookieinlen ATTRIBUTE_UNUSED, + unsigned int flags, + int cancelled) +{ + libxlDriverPrivatePtr driver = domain->conn->privateData; + virDomainObjPtr vm = NULL; + + virCheckFlags(LIBXL_MIGRATION_FLAGS, -1); + if (virTypedParamsValidate(params, nparams, LIBXL_MIGRATION_PARAMETERS) < 0) + return -1; + + if (!(vm = libxlDomObjFromDomain(domain))) + return -1; + + if (virDomainMigrateConfirm3ParamsEnsureACL(domain->conn, vm->def) < 0) { + virObjectUnlock(vm); + return -1; + } + + return libxlDomainMigrationConfirm(driver, vm, flags, cancelled); +} + static virDriver libxlDriver = { .no = VIR_DRV_LIBXL, @@ -4394,6 +4613,11 @@ static virDriver libxlDriver = { .nodeDeviceDetachFlags = libxlNodeDeviceDetachFlags, /* 1.2.3 */ .nodeDeviceReAttach = libxlNodeDeviceReAttach, /* 1.2.3 */ .nodeDeviceReset = libxlNodeDeviceReset, /* 1.2.3 */ + .domainMigrateBegin3Params = libxlDomainMigrateBegin3Params, /* 1.2.3 */ + .domainMigratePrepare3Params = libxlDomainMigratePrepare3Params, /* 1.2.3 */ + .domainMigratePerform3Params = libxlDomainMigratePerform3Params, /* 1.2.3 */ + .domainMigrateFinish3Params = libxlDomainMigrateFinish3Params, /* 1.2.3 */ + .domainMigrateConfirm3Params = libxlDomainMigrateConfirm3Params, /* 1.2.3 */ }; static virStateDriver libxlStateDriver = { diff --git a/src/libxl/libxl_migration.c b/src/libxl/libxl_migration.c new file mode 100644 index 0000000..7776934 --- /dev/null +++ b/src/libxl/libxl_migration.c @@ -0,0 +1,978 @@ +/* + * libxl_migration.c: methods for handling migration with libxenlight + * + * Copyright (C) 2014 SUSE LINUX Products GmbH, Nuernberg, Germany. + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2.1 of the License, or (at your option) any later version. + * + * This library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library. If not, see + * <http://www.gnu.org/licenses/>. + * + * Authors: + * Jim Fehlig <jfehlig@suse.com> + * Chunyan Liu <cyliu@suse.com> + */ + +#include <config.h> + +#include "internal.h" +#include "virlog.h" +#include "virerror.h" +#include "virconf.h" +#include "datatypes.h" +#include "virfile.h" +#include "viralloc.h" +#include "viruuid.h" +#include "vircommand.h" +#include "virstring.h" +#include "rpc/virnetsocket.h" +#include "libxl_domain.h" +#include "libxl_driver.h" +#include "libxl_conf.h" +#include "libxl_migration.h" + +#define VIR_FROM_THIS VIR_FROM_LIBXL + +VIR_LOG_INIT("libxl.libxl_migration"); + +#define LIBXL_MIGRATION_PROTO_VERSION 1 +#define LIBXL_MIGRATION_MSG_MAX_SIZE 512 + +typedef struct _libxlMigrateReceiveArgs { + virConnectPtr conn; + virDomainObjPtr vm; + + /* for freeing listen sockets */ + virNetSocketPtr *socks; + size_t nsocks; +} libxlMigrateReceiveArgs; + +/* + * For future extensibility, a simple messaging protocol used to send migration + * data between libxl hosts. The message is encapsulated in json and currently + * includes the following entries: + * + * {"libvirt-libxl-mig-msg" : + * {"version" : $ver}, + * {"state" : $state}, + * {"status" : $status} + * } + * + * Possible $state values are "negotiate-version", "send-binary-data", + * "sending-binary-data", "received-binary-data", "done", and "error". + * + * Migration between source and destination libxl hosts is performed with the + * following message exchange: + * + * - src->dst: connect + * - dst->src: state="negotiate-version", version=LIBXL_MIGRATION_PROTO_VERSION + * - src->dst: state-"negotiate-version", + * version=min(dst ver, LIBXL_MIGRATION_PROTO_VERSION) + * - dst->src: state="send-binary-data", version=negotiated_version + * - src->dst: state="sending-binary-data", version=negotiated_version + * _ src->dst: binary migration data + * - dst->src: state="received-binary-data", version=negotiated_version + * - src->dst: state="done", version=negotiated_version + * + */ + +static virJSONValuePtr +libxlMigrationMsgNew(const char *state) +{ + virJSONValuePtr msg; + virJSONValuePtr body; + + if (!(msg = virJSONValueNewObject())) + return NULL; + + if (!(body = virJSONValueNewObject())) { + virJSONValueFree(msg); + return NULL; + } + + virJSONValueObjectAppendNumberInt(body, "version", + LIBXL_MIGRATION_PROTO_VERSION); + virJSONValueObjectAppendString(body, "state", state); + virJSONValueObjectAppendNumberInt(body, "status", 0); + + virJSONValueObjectAppend(msg, "libvirt-libxl-mig-msg", body); + + return msg; +} + +static bool +libxlMigrationMsgCheckState(virJSONValuePtr message, const char *state) +{ + virJSONValuePtr body; + const char *msg_state; + + if (!(body = virJSONValueObjectGet(message, "libvirt-libxl-mig-msg"))) + return false; + + msg_state = virJSONValueObjectGetString(body, "state"); + if (!msg_state || STRNEQ(msg_state, state)) + return false; + + return true; +} + +static void +libxlMigrationMsgSetStringField(virJSONValuePtr message, + const char *field, + const char *val) +{ + virJSONValuePtr body; + + if ((body = virJSONValueObjectGet(message, "libvirt-libxl-mig-msg"))) { + virJSONValueObjectRemoveKey(body, field, NULL); + virJSONValueObjectAppendString(body, field, val); + } +} + +static void +libxlMigrationMsgSetIntField(virJSONValuePtr message, + const char *field, + int val) +{ + virJSONValuePtr body; + + if ((body = virJSONValueObjectGet(message, "libvirt-libxl-mig-msg"))) { + virJSONValueObjectRemoveKey(body, field, NULL); + virJSONValueObjectAppendNumberInt(body, field, val); + } +} + +static int +libxlMigrationMsgGetIntField(virJSONValuePtr message, + const char *field, + int *val) +{ + virJSONValuePtr body; + + if (!(body = virJSONValueObjectGet(message, "libvirt-libxl-mig-msg"))) + return -1; + + if (virJSONValueObjectGetNumberInt(body, field, val) < 0) + return -1; + + return 0; +} + + +/* + * Send a migration message with 'status' field set to @status. + */ +static int +libxlMigrationMsgSend(int fd, virJSONValuePtr message, int status) +{ + int ret = -1; + size_t len; + char *msgstr; + + libxlMigrationMsgSetIntField(message, "status", status); + if (!(msgstr = virJSONValueToString(message, false))) { + virReportError(VIR_ERR_OPERATION_FAILED, "%s", + _("Malformed migration message")); + return -1; + } + + VIR_DEBUG("Sending migration message %s", msgstr); + len = strlen(msgstr) + 1; + if (safewrite(fd, msgstr, len) != len) { + virReportError(VIR_ERR_OPERATION_FAILED, "%s", + _("Failed to send migration message")); + goto cleanup; + } + + ret = 0; + + cleanup: + VIR_FREE(msgstr); + return ret; +} + +static virJSONValuePtr +libxlMigrationMsgReceive(int fd) +{ + char buf[LIBXL_MIGRATION_MSG_MAX_SIZE]; + int ret; + virJSONValuePtr msg = NULL; + size_t i; + + /* + * Message is small and NULL-terminated. Read a byte at a time + * until encountering the null-termination. + */ + for (i = 0; i < LIBXL_MIGRATION_MSG_MAX_SIZE;) { + ret = saferead(fd, &(buf[i]), 1); + if (ret == 1) + if (buf[i++] == '\0') + break; + + /* bail out if eof or failure != EAGAIN */ + if ((ret == 0) || (ret == -1 && errno != EAGAIN)) { + virReportError(VIR_ERR_OPERATION_FAILED, "%s", + _("Failed to receive migration message")); + return NULL; + } + } + + if (i == LIBXL_MIGRATION_MSG_MAX_SIZE) { + virReportError(VIR_ERR_OPERATION_FAILED, "%s", + _("Migration message exceeded max size")); + return NULL; + } + + VIR_DEBUG("Received migration message %s", buf); + if (!(msg = virJSONValueFromString(buf))) + goto error; + + /* Verify a libvirt-libxl-mig-msg was received */ + if (!(virJSONValueObjectGet(msg, "libvirt-libxl-mig-msg"))) + goto error; + + return msg; + + error: + virReportError(VIR_ERR_OPERATION_FAILED, "%s", + _("Malformed migration message")); + virJSONValueFree(msg); + return NULL; +} + +static int +libxlMigrationSrcNegotiate(int fd) +{ + int ret = -1; + virJSONValuePtr msg; + int dstver; + + if (!(msg = libxlMigrationMsgReceive(fd))) + return -1; + + if (!libxlMigrationMsgCheckState(msg, "negotiate-version")) { + virReportError(VIR_ERR_OPERATION_FAILED, "%s", + _("Failed to negotiate libxl " + "migration protocol version")); + goto cleanup; + } + + /* + * ACK by returning the message, with version set to + * min(dest ver, src ver) + */ + if (libxlMigrationMsgGetIntField(msg, "version", &dstver) < 0) + goto cleanup; + + if (dstver > LIBXL_MIGRATION_PROTO_VERSION) + libxlMigrationMsgSetIntField(msg, + "version", + LIBXL_MIGRATION_PROTO_VERSION); + + if (libxlMigrationMsgSend(fd, msg, 0) < 0) + goto cleanup; + + ret = 0; + + cleanup: + virJSONValueFree(msg); + return ret; +} + +static int +libxlMigrationDstNegotiate(int fd, virJSONValuePtr *message) +{ + virJSONValuePtr msg; + + if (!(msg = libxlMigrationMsgNew("negotiate-version"))) + return -1; + + if (libxlMigrationMsgSend(fd, msg, 0) < 0) { + virJSONValueFree(msg); + return -1; + } + + /* + * Receive ACK. src set version=min(dst ver, highest src ver), + * which is the negotiated version. Use this message with + * negotiated version throughout the transaction. + */ + virJSONValueFree(msg); + if (!(msg = libxlMigrationMsgReceive(fd))) + return -1; + + *message = msg; + return 0; +} + +static int +libxlMigrationSrcReady(int fd) +{ + int ret = -1; + virJSONValuePtr msg; + + if (!(msg = libxlMigrationMsgReceive(fd))) + return -1; + + if (!libxlMigrationMsgCheckState(msg, "send-binary-data")) { + virReportError(VIR_ERR_OPERATION_FAILED, "%s", + _("Failed to receive 'send-binary-data' message " + "from destination libxl migration host")); + goto cleanup; + } + + /* ACK by returning the message with state sending */ + libxlMigrationMsgSetStringField(msg, "state", "sending-binary-data"); + if (libxlMigrationMsgSend(fd, msg, 0) < 0) + goto cleanup; + + ret = 0; + + cleanup: + virJSONValueFree(msg); + return ret; +} + +static int +libxlMigrationDstReady(int fd, virJSONValuePtr msg) +{ + int ret = -1; + virJSONValuePtr tmp = NULL; + + libxlMigrationMsgSetStringField(msg, "state", "send-binary-data"); + if (libxlMigrationMsgSend(fd, msg, 0) < 0) + return -1; + + /* Receive ACK, state sending */ + if (!(tmp = libxlMigrationMsgReceive(fd))) + return -1; + if (!libxlMigrationMsgCheckState(tmp, "sending-binary-data")) { + virReportError(VIR_ERR_OPERATION_FAILED, "%s", + _("Failed to receive 'sending-binary-data' message " + "from source libxl migration host")); + goto cleanup; + } + + ret = 0; + + cleanup: + virJSONValueFree(tmp); + return ret; +} + +static int +libxlMigrationSrcDone(int fd) +{ + int ret = -1; + virJSONValuePtr msg; + + if (!(msg = libxlMigrationMsgReceive(fd))) + return -1; + + if (!libxlMigrationMsgCheckState(msg, "received-binary-data")) { + virReportError(VIR_ERR_OPERATION_FAILED, "%s", + _("Failed to receive 'received-binary-data' message " + "from destination libxl migration host")); + goto cleanup; + } + + /* ACK by returning the message with state done */ + libxlMigrationMsgSetStringField(msg, "state", "done"); + if (libxlMigrationMsgSend(fd, msg, 0) < 0) + goto cleanup; + + ret = 0; + + cleanup: + virJSONValueFree(msg); + return ret; +} + +static int +libxlMigrationDestDone(int fd, virJSONValuePtr msg) +{ + int ret = -1; + virJSONValuePtr tmp; + + libxlMigrationMsgSetStringField(msg, "state", "received-binary-data"); + if (libxlMigrationMsgSend(fd, msg, 0) < 0) + return -1; + + /* Receive ACK, state done */ + if (!(tmp = libxlMigrationMsgReceive(fd))) + return -1; + if (!libxlMigrationMsgCheckState(tmp, "done")) { + virReportError(VIR_ERR_OPERATION_FAILED, "%s", + _("Failed to receive 'done' message " + "from source libxl migration host")); + goto cleanup; + } + + ret = 0; + + cleanup: + virJSONValueFree(tmp); + return ret; +} + +static void +libxlMigrationSrcFailed(int fd, int status) +{ + virJSONValuePtr msg; + + if (!(msg = libxlMigrationMsgNew("error"))) + return; + libxlMigrationMsgSend(fd, msg, status); + virJSONValueFree(msg); +} + +static void +libxlMigrationDstFailed(int fd, virJSONValuePtr msg, int status) +{ + libxlMigrationMsgSetStringField(msg, "state", "error"); + libxlMigrationMsgSend(fd, msg, status); +} + +static void +libxlDoMigrateReceive(virNetSocketPtr sock, + int events ATTRIBUTE_UNUSED, + void *opaque) +{ + libxlMigrateReceiveArgs *data = opaque; + virConnectPtr conn = data->conn; + virDomainObjPtr vm = data->vm; + libxlDomainObjPrivatePtr priv = vm->privateData; + virNetSocketPtr *socks = data->socks; + size_t nsocks = data->nsocks; + libxlDriverPrivatePtr driver = conn->privateData; + virNetSocketPtr client_sock; + virJSONValuePtr mig_msg = NULL; + int recvfd; + size_t i; + int ret; + + virNetSocketAccept(sock, &client_sock); + if (client_sock == NULL) { + virReportError(VIR_ERR_OPERATION_INVALID, "%s", + _("Fail to accept migration connection")); + goto cleanup; + } + VIR_DEBUG("Accepted migration connection\n"); + recvfd = virNetSocketDupFD(client_sock, true); + virObjectUnref(client_sock); + + if (libxlMigrationDstNegotiate(recvfd, &mig_msg) < 0) + goto cleanup; + + if (libxlMigrationDstReady(recvfd, mig_msg) < 0) + goto cleanup; + + virObjectLock(vm); + ret = libxlDomainStart(driver, vm, false, recvfd); + virObjectUnlock(vm); + + if (ret < 0) { + libxlMigrationDstFailed(recvfd, mig_msg, ret); + virReportError(VIR_ERR_INTERNAL_ERROR, "%s", + _("Failed to restore domain with libxenlight")); + if (!vm->persistent) + virDomainObjListRemove(driver->domains, vm); + goto cleanup; + } + + if (libxlMigrationDestDone(recvfd, mig_msg) < 0) { + virReportError(VIR_ERR_OPERATION_FAILED, "%s", + _("Failed to notify sender that migration completed")); + goto cleanup_dom; + } + + /* Remove all listen socks from event handler, and close them. */ + for (i = 0; i < nsocks; i++) { + virNetSocketUpdateIOCallback(socks[i], 0); + virNetSocketRemoveIOCallback(socks[i]); + virNetSocketClose(socks[i]); + virObjectUnref(socks[i]); + } + VIR_FREE(socks); + goto cleanup; + + cleanup_dom: + libxl_domain_destroy(priv->ctx, vm->def->id, NULL); + vm->def->id = -1; + if (!vm->persistent) + virDomainObjListRemove(driver->domains, vm); + + cleanup: + VIR_FORCE_CLOSE(recvfd); + virJSONValueFree(mig_msg); + VIR_FREE(opaque); + return; +} + +static int +libxlDoMigrateSend(libxlDriverPrivatePtr driver, + virDomainObjPtr vm, + unsigned long flags, + int sockfd) +{ + libxlDomainObjPrivatePtr priv; + libxlDriverConfigPtr cfg = libxlDriverConfigGet(driver); + virObjectEventPtr event = NULL; + int xl_flags = 0; + int ret = -1; + + if (flags & VIR_MIGRATE_LIVE) + xl_flags = LIBXL_SUSPEND_LIVE; + + priv = vm->privateData; + + if (libxlMigrationSrcNegotiate(sockfd) < 0) + goto cleanup; + + if (libxlMigrationSrcReady(sockfd) < 0) + goto cleanup; + + ret = libxl_domain_suspend(priv->ctx, vm->def->id, sockfd, + xl_flags, NULL); + if (ret != 0) { + libxlMigrationSrcFailed(sockfd, ret); + virReportError(VIR_ERR_INTERNAL_ERROR, + _("Failed to save domain '%d' with libxenlight"), + vm->def->id); + ret = -1; + goto cleanup; + } + + if (libxlMigrationSrcDone(sockfd) < 0) { + if (libxl_domain_resume(priv->ctx, vm->def->id, 0, 0) != 0) { + VIR_DEBUG("Failed to resume domain '%d' with libxenlight", + vm->def->id); + virDomainObjSetState(vm, VIR_DOMAIN_PAUSED, + VIR_DOMAIN_PAUSED_MIGRATION); + event = virDomainEventLifecycleNewFromObj(vm, VIR_DOMAIN_EVENT_SUSPENDED, + VIR_DOMAIN_EVENT_SUSPENDED_MIGRATED); + if (virDomainSaveStatus(driver->xmlopt, cfg->stateDir, vm) < 0) + goto cleanup; + } + goto cleanup; + } + + ret = 0; + + cleanup: + if (event) + libxlDomainEventQueue(driver, event); + virObjectUnref(cfg); + return ret; +} + +static bool +libxlDomainMigrationIsAllowed(virDomainDefPtr def) +{ + /* Migration is not allowed if definition contains any hostdevs */ + if (def->nhostdevs > 0) { + virReportError(VIR_ERR_OPERATION_INVALID, "%s", + _("domain has assigned host devices")); + return false; + } + + return true; +} + +char * +libxlDomainMigrationBegin(virConnectPtr conn, + virDomainObjPtr vm, + const char *xmlin) +{ + libxlDriverPrivatePtr driver = conn->privateData; + libxlDriverConfigPtr cfg = libxlDriverConfigGet(driver); + virDomainDefPtr tmpdef = NULL; + virDomainDefPtr def; + char *xml = NULL; + + if (libxlDomainObjBeginJob(driver, vm, LIBXL_JOB_MODIFY) < 0) + goto cleanup; + + if (xmlin) { + if (!(tmpdef = virDomainDefParseString(xmlin, cfg->caps, + driver->xmlopt, + 1 << VIR_DOMAIN_VIRT_XEN, + VIR_DOMAIN_XML_INACTIVE))) + goto endjob; + + def = tmpdef; + } else { + def = vm->def; + } + + if (!libxlDomainMigrationIsAllowed(def)) + goto endjob; + + xml = virDomainDefFormat(def, VIR_DOMAIN_XML_SECURE); + + cleanup: + if (vm) + virObjectUnlock(vm); + + virDomainDefFree(tmpdef); + virObjectUnref(cfg); + return xml; + + endjob: + if (!libxlDomainObjEndJob(driver, vm)) + vm = NULL; + goto cleanup; +} + +virDomainDefPtr +libxlDomainMigrationPrepareDef(libxlDriverPrivatePtr driver, + const char *dom_xml, + const char *dname) +{ + libxlDriverConfigPtr cfg = libxlDriverConfigGet(driver); + virDomainDefPtr def; + char *name = NULL; + + if (!dom_xml) { + virReportError(VIR_ERR_INTERNAL_ERROR, "%s", + _("no domain XML passed")); + return NULL; + } + + if (!(def = virDomainDefParseString(dom_xml, cfg->caps, driver->xmlopt, + 1 << VIR_DOMAIN_VIRT_XEN, + VIR_DOMAIN_XML_INACTIVE))) + goto cleanup; + + if (dname) { + name = def->name; + if (VIR_STRDUP(def->name, dname) < 0) { + virDomainDefFree(def); + def = NULL; + } + } + + cleanup: + virObjectUnref(cfg); + VIR_FREE(name); + return def; +} + +int +libxlDomainMigrationPrepare(virConnectPtr dconn, + virDomainDefPtr def, + const char *uri_in, + char **uri_out) +{ + libxlDriverPrivatePtr driver = dconn->privateData; + virDomainObjPtr vm = NULL; + char *hostname = NULL; + unsigned short port; + char portstr[100]; + virURIPtr uri = NULL; + virNetSocketPtr *socks = NULL; + size_t nsocks = 0; + int nsocks_listen = 0; + libxlMigrateReceiveArgs *args; + size_t i; + int ret = -1; + + if (!(vm = virDomainObjListAdd(driver->domains, def, + driver->xmlopt, + VIR_DOMAIN_OBJ_LIST_ADD_LIVE | + VIR_DOMAIN_OBJ_LIST_ADD_CHECK_LIVE, + NULL))) + goto cleanup; + + /* Create socket connection to receive migration data */ + if (!uri_in) { + if ((hostname = virGetHostname()) == NULL) + goto cleanup; + + if (STRPREFIX(hostname, "localhost")) { + virReportError(VIR_ERR_INTERNAL_ERROR, "%s", + _("hostname on destination resolved to localhost," + " but migration requires an FQDN")); + goto cleanup; + } + + if (virPortAllocatorAcquire(driver->migrationPorts, &port) < 0) + goto cleanup; + + if (virAsprintf(uri_out, "tcp://%s:%d", hostname, port) < 0) + goto cleanup; + } else { + if (!(STRPREFIX(uri_in, "tcp://"))) { + /* not full URI, add prefix tcp:// */ + char *tmp; + if (virAsprintf(&tmp, "tcp://%s", uri_in) < 0) + goto cleanup; + uri = virURIParse(tmp); + VIR_FREE(tmp); + } else { + uri = virURIParse(uri_in); + } + + if (uri == NULL) { + virReportError(VIR_ERR_INVALID_ARG, + _("unable to parse URI: %s"), + uri_in); + goto cleanup; + } + + if (uri->server == NULL) { + virReportError(VIR_ERR_INVALID_ARG, + _("missing host in migration URI: %s"), + uri_in); + goto cleanup; + } else { + hostname = uri->server; + } + + if (uri->port == 0) { + if (virPortAllocatorAcquire(driver->migrationPorts, &port) < 0) + goto cleanup; + + } else { + port = uri->port; + } + + if (virAsprintf(uri_out, "tcp://%s:%d", hostname, port) < 0) + goto cleanup; + } + + snprintf(portstr, sizeof(portstr), "%d", port); + + if (virNetSocketNewListenTCP(hostname, portstr, &socks, &nsocks) < 0) { + virReportError(VIR_ERR_OPERATION_FAILED, "%s", + _("Fail to create socket for incoming migration")); + goto cleanup; + } + + if (VIR_ALLOC(args) < 0) + goto cleanup; + + args->conn = dconn; + args->vm = vm; + args->socks = socks; + args->nsocks = nsocks; + + for (i = 0; i < nsocks; i++) { + if (virNetSocketSetBlocking(socks[i], true) < 0) + continue; + + if (virNetSocketListen(socks[i], 1) < 0) + continue; + + if (virNetSocketAddIOCallback(socks[i], + 0, + libxlDoMigrateReceive, + args, + NULL) < 0) { + continue; + } + + virNetSocketUpdateIOCallback(socks[i], VIR_EVENT_HANDLE_READABLE); + nsocks_listen++; + } + + if (!nsocks_listen) + goto cleanup; + + ret = 0; + goto done; + + cleanup: + for (i = 0; i < nsocks; i++) { + virNetSocketClose(socks[i]); + virObjectUnref(socks[i]); + } + VIR_FREE(socks); + + done: + virURIFree(uri); + if (vm) + virObjectUnlock(vm); + return ret; +} + +int +libxlDomainMigrationPerform(libxlDriverPrivatePtr driver, + virDomainObjPtr vm, + const char *dom_xml ATTRIBUTE_UNUSED, + const char *dconnuri ATTRIBUTE_UNUSED, + const char *uri_str, + const char *dname ATTRIBUTE_UNUSED, + unsigned int flags) +{ + char *hostname = NULL; + unsigned short port = 0; + char portstr[100]; + virURIPtr uri = NULL; + virNetSocketPtr sock; + int sockfd = -1; + int saved_errno = EINVAL; + int ret = -1; + + /* parse dst host:port from uri */ + uri = virURIParse(uri_str); + if (uri == NULL || uri->server == NULL || uri->port == 0) + goto cleanup; + + hostname = uri->server; + port = uri->port; + snprintf(portstr, sizeof(portstr), "%d", port); + + /* socket connect to dst host:port */ + if (virNetSocketNewConnectTCP(hostname, portstr, &sock) < 0) { + virReportSystemError(saved_errno, + _("unable to connect to '%s:%s'"), + hostname, portstr); + goto cleanup; + } + + if (virNetSocketSetBlocking(sock, true) < 0) { + virObjectUnref(sock); + goto cleanup; + } + + sockfd = virNetSocketDupFD(sock, true); + virObjectUnref(sock); + + /* suspend vm and send saved data to dst through socket fd */ + virObjectUnlock(vm); + ret = libxlDoMigrateSend(driver, vm, flags, sockfd); + virObjectLock(vm); + + cleanup: + /* If failure, terminate the job started in MigrationBegin */ + if (ret == -1) { + if (libxlDomainObjEndJob(driver, vm)) + virObjectUnlock(vm); + } + VIR_FORCE_CLOSE(sockfd); + virURIFree(uri); + return ret; +} + +virDomainPtr +libxlDomainMigrationFinish(virConnectPtr dconn, + virDomainObjPtr vm, + unsigned int flags, + int cancelled) +{ + libxlDriverPrivatePtr driver = dconn->privateData; + libxlDriverConfigPtr cfg = libxlDriverConfigGet(driver); + libxlDomainObjPrivatePtr priv = vm->privateData; + virObjectEventPtr event = NULL; + virDomainPtr dom = NULL; + + virPortAllocatorRelease(driver->migrationPorts, priv->migrationPort); + priv->migrationPort = 0; + + if (cancelled) + goto cleanup; + + if (!(flags & VIR_MIGRATE_PAUSED)) { + if (libxl_domain_unpause(priv->ctx, vm->def->id) != 0) { + virReportError(VIR_ERR_OPERATION_FAILED, "%s", + _("Failed to unpause domain")); + goto cleanup; + } + + virDomainObjSetState(vm, VIR_DOMAIN_RUNNING, + VIR_DOMAIN_RUNNING_MIGRATED); + event = virDomainEventLifecycleNewFromObj(vm, + VIR_DOMAIN_EVENT_RESUMED, + VIR_DOMAIN_EVENT_RESUMED_MIGRATED); + } else { + virDomainObjSetState(vm, VIR_DOMAIN_PAUSED, VIR_DOMAIN_PAUSED_USER); + event = virDomainEventLifecycleNewFromObj(vm, + VIR_DOMAIN_EVENT_SUSPENDED, + VIR_DOMAIN_EVENT_SUSPENDED_PAUSED); + } + + if (virDomainSaveStatus(driver->xmlopt, cfg->stateDir, vm) < 0) + goto cleanup; + + dom = virGetDomain(dconn, vm->def->name, vm->def->uuid); + + if (dom == NULL) { + libxl_domain_destroy(priv->ctx, vm->def->id, NULL); + libxlDomainCleanup(driver, vm, VIR_DOMAIN_SHUTOFF_FAILED); + event = virDomainEventLifecycleNewFromObj(vm, VIR_DOMAIN_EVENT_STOPPED, + VIR_DOMAIN_EVENT_STOPPED_FAILED); + libxlDomainEventQueue(driver, event); + } + + cleanup: + if (event) + libxlDomainEventQueue(driver, event); + if (vm) + virObjectUnlock(vm); + virObjectUnref(cfg); + return dom; +} + +int +libxlDomainMigrationConfirm(libxlDriverPrivatePtr driver, + virDomainObjPtr vm, + unsigned int flags, + int cancelled) +{ + libxlDriverConfigPtr cfg = libxlDriverConfigGet(driver); + libxlDomainObjPrivatePtr priv = vm->privateData; + virObjectEventPtr event = NULL; + int ret = -1; + + if (cancelled) { + virReportError(VIR_ERR_INTERNAL_ERROR, "%s", + _("migration failed, attempting to resume on source host")); + if (libxl_domain_resume(priv->ctx, vm->def->id, 1, 0) == 0) { + ret = 0; + } else { + VIR_DEBUG("Unable to resume domain '%s' after failed migration", + vm->def->name); + virDomainObjSetState(vm, VIR_DOMAIN_PAUSED, + VIR_DOMAIN_PAUSED_MIGRATION); + event = virDomainEventLifecycleNewFromObj(vm, VIR_DOMAIN_EVENT_SUSPENDED, + VIR_DOMAIN_EVENT_SUSPENDED_MIGRATED); + ignore_value(virDomainSaveStatus(driver->xmlopt, cfg->stateDir, vm)); + } + goto cleanup; + } + + libxl_domain_destroy(priv->ctx, vm->def->id, NULL); + libxlDomainCleanup(driver, vm, VIR_DOMAIN_SHUTOFF_MIGRATED); + event = virDomainEventLifecycleNewFromObj(vm, VIR_DOMAIN_EVENT_STOPPED, + VIR_DOMAIN_EVENT_STOPPED_MIGRATED); + + VIR_DEBUG("Domain '%s' successfully migrated", vm->def->name); + + if (flags & VIR_MIGRATE_UNDEFINE_SOURCE) + virDomainDeleteConfig(cfg->configDir, cfg->autostartDir, vm); + + if (!vm->persistent || (flags & VIR_MIGRATE_UNDEFINE_SOURCE)) + virDomainObjListRemove(driver->domains, vm); + + ret = 0; + + cleanup: + if (!libxlDomainObjEndJob(driver, vm)) + vm = NULL; + if (event) + libxlDomainEventQueue(driver, event); + if (vm) + virObjectUnlock(vm); + virObjectUnref(cfg); + return ret; +} diff --git a/src/libxl/libxl_migration.h b/src/libxl/libxl_migration.h new file mode 100644 index 0000000..63d8bdc --- /dev/null +++ b/src/libxl/libxl_migration.h @@ -0,0 +1,78 @@ +/* + * libxl_migration.h: methods for handling migration with libxenlight + * + * Copyright (c) 2014 SUSE LINUX Products GmbH, Nuernberg, Germany. + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2.1 of the License, or (at your option) any later version. + * + * This library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library. If not, see + * <http://www.gnu.org/licenses/>. + * + * Authors: + * Jim Fehlig <jfehlig@suse.com> + */ + +#ifndef LIBXL_MIGRATION_H +# define LIBXL_MIGRATION_H + +# include "libxl_conf.h" + +# define LIBXL_MIGRATION_FLAGS \ + (VIR_MIGRATE_LIVE | \ + VIR_MIGRATE_UNDEFINE_SOURCE | \ + VIR_MIGRATE_PAUSED) + +/* All supported migration parameters and their types. */ +# define LIBXL_MIGRATION_PARAMETERS \ + VIR_MIGRATE_PARAM_URI, VIR_TYPED_PARAM_STRING, \ + VIR_MIGRATE_PARAM_DEST_NAME, VIR_TYPED_PARAM_STRING, \ + VIR_MIGRATE_PARAM_DEST_XML, VIR_TYPED_PARAM_STRING, \ + NULL + +char * +libxlDomainMigrationBegin(virConnectPtr conn, + virDomainObjPtr vm, + const char *xmlin); + +virDomainDefPtr +libxlDomainMigrationPrepareDef(libxlDriverPrivatePtr driver, + const char *dom_xml, + const char *dname); + +int +libxlDomainMigrationPrepare(virConnectPtr dconn, + virDomainDefPtr def, + const char *uri_in, + char **uri_out); + +int +libxlDomainMigrationPerform(libxlDriverPrivatePtr driver, + virDomainObjPtr vm, + const char *dom_xml, + const char *dconnuri, + const char *uri_str, + const char *dname, + unsigned int flags); + +virDomainPtr +libxlDomainMigrationFinish(virConnectPtr dconn, + virDomainObjPtr vm, + unsigned int flags, + int cancelled); + +int +libxlDomainMigrationConfirm(libxlDriverPrivatePtr driver, + virDomainObjPtr vm, + unsigned int flags, + int cancelled); + +#endif /* LIBXL_DRIVER_H */ -- 1.8.1.4

On Mon, Apr 28, 2014 at 10:43:10AM -0600, Jim Fehlig wrote:
This patch adds initial migration support to the libxl driver, using the VIR_DRV_FEATURE_MIGRATION_PARAMS family of migration functions.
Signed-off-by: Jim Fehlig <jfehlig@suse.com> ---
V3 here https://www.redhat.com/archives/libvir-list/2014-April/msg00968.html
In V4: - Code cleanup - Improved error handling
Although this patch has been floating around for a long time, not sure if it is 1.2.4 material since it brings a new feature to the libxl driver.
+/* + * For future extensibility, a simple messaging protocol used to send migration + * data between libxl hosts. The message is encapsulated in json and currently + * includes the following entries: + * + * {"libvirt-libxl-mig-msg" : + * {"version" : $ver}, + * {"state" : $state}, + * {"status" : $status} + * } + * + * Possible $state values are "negotiate-version", "send-binary-data", + * "sending-binary-data", "received-binary-data", "done", and "error". + * + * Migration between source and destination libxl hosts is performed with the + * following message exchange: + * + * - src->dst: connect + * - dst->src: state="negotiate-version", version=LIBXL_MIGRATION_PROTO_VERSION + * - src->dst: state-"negotiate-version", + * version=min(dst ver, LIBXL_MIGRATION_PROTO_VERSION) + * - dst->src: state="send-binary-data", version=negotiated_version + * - src->dst: state="sending-binary-data", version=negotiated_version + * _ src->dst: binary migration data + * - dst->src: state="received-binary-data", version=negotiated_version + * - src->dst: state="done", version=negotiated_version + * + */
Maybe I'm missing something, but where is the actual migration payload data being transferred ? None of the messages above contain any data ? I'm also a little wary of the fact that you're building a bi-directional control structure here. This seems to have alot of overlap with the handshake / control structure already built into the virDomainMigrateXXX steps, and willmake it impossible for you to support the tunnelled migration feature which relies on the migration data stream being unidirectional. Regards, Daniel -- |: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :| |: http://libvirt.org -o- http://virt-manager.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :|

Daniel P. Berrange wrote:
On Mon, Apr 28, 2014 at 10:43:10AM -0600, Jim Fehlig wrote:
This patch adds initial migration support to the libxl driver, using the VIR_DRV_FEATURE_MIGRATION_PARAMS family of migration functions.
Signed-off-by: Jim Fehlig <jfehlig@suse.com> ---
V3 here https://www.redhat.com/archives/libvir-list/2014-April/msg00968.html
In V4: - Code cleanup - Improved error handling
Although this patch has been floating around for a long time, not sure if it is 1.2.4 material since it brings a new feature to the libxl driver.
+/* + * For future extensibility, a simple messaging protocol used to send migration + * data between libxl hosts. The message is encapsulated in json and currently + * includes the following entries: + * + * {"libvirt-libxl-mig-msg" : + * {"version" : $ver}, + * {"state" : $state}, + * {"status" : $status} + * } + * + * Possible $state values are "negotiate-version", "send-binary-data", + * "sending-binary-data", "received-binary-data", "done", and "error". + * + * Migration between source and destination libxl hosts is performed with the + * following message exchange: + * + * - src->dst: connect + * - dst->src: state="negotiate-version", version=LIBXL_MIGRATION_PROTO_VERSION + * - src->dst: state-"negotiate-version", + * version=min(dst ver, LIBXL_MIGRATION_PROTO_VERSION) + * - dst->src: state="send-binary-data", version=negotiated_version + * - src->dst: state="sending-binary-data", version=negotiated_version + * _ src->dst: binary migration data ^^^^ Migration data is sent here.
+ * - dst->src: state="received-binary-data", version=negotiated_version + * - src->dst: state="done", version=negotiated_version + * + */
Maybe I'm missing something, but where is the actual migration payload data being transferred ? None of the messages above contain any data ?
See above.
I'm also a little wary of the fact that you're building a bi-directional control structure here. This seems to have alot of overlap with the handshake / control structure already built into the virDomainMigrateXXX steps,
Heh, that was on my mind when responding to Michal's question about the previous, simpler control structure https://www.redhat.com/archives/libvir-list/2014-March/msg01196.html There I mentioned doing most of the control work using libvirt's V3 migration protocol, keeping the libxl side of things simple. The intent with V4 of this patch was to make the simple libxl-side control structure a bit extensible. But stepping back and thinking about this more, I think the libxl-side control could be removed completely and all control handled by the libvirt migration protocol. During the perform phase, simply send the migration data to the destination, which was prepared to receive it during the prepare phase. Does this sound reasonable?
and willmake it impossible for you to support the tunnelled migration feature which relies on the migration data stream being unidirectional.
Good point. Another reason to remove the libxl-side control and simply pass the migration data to the destination. Regards, Jim
participants (2)
-
Daniel P. Berrange
-
Jim Fehlig