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Re: [libvirt] [PATCH v3 2/2] libxl: add tunnelled migration support




On 02/15/2017 11:17 AM, Joao Martins wrote:
> From: Bob Liu <bob liu oracle com>
> 
> Tunnelled migration doesn't require any extra network connections
> beside the libvirt daemon.  It's capable of strong encryption and the
> default option of openstack-nova.
> 
> This patch adds the tunnelled migration(Tunnel3params) support to
> libxl.  On the source side, the data flow is:
> 
>  * libxlDoMigrateSend() -> pipe libxlTunnel3MigrationFunc() polls pipe
>  * out and then write to dest stream.
> 
> While on the destination side:
>  * Stream -> pipe -> 'recvfd of libxlDomainStartRestore'
> 
> The usage is the same as p2p migration, execpt adding one extra
> '--tunnelled' to the libvirt p2p migration command.
> 
> Signed-off-by: Bob Liu <bob liu oracle com>
> Signed-off-by: Joao Martins <joao m martins oracle com>
> ---
> v3:
>  * virStream{Send,Finish} and VIR_ALLOC_N already report errors,
>  hence removing the virReportError calls from its error paths.
>  * Revert top-level migration APIs to initial v1 approach.
> v2:
>  ( Comments from Jim )
>  * Adjust common preparetunnel function reflecting v1 suggestions
>    - Using common top-level Prepare function by adding is_tunnel variable
>    - Using libxl_migration PrepareAny added in patch 1
>    - virHook support in PrepareTunnel3
>  * Move virThreadPtr from libxlTunnelMigrationThread into libxlTunnelControl
>  * Rename function local variable from tmThreadPtr to arg
>  * Remove redundant assignment "tmThreadPtr = &tc->tmThread;" always being not
>  null.
>  * Adjust debug message to "poll returned 0" as opposed to "poll got
>  timeout" as the latter might not always be the case.
> ---
>  src/libxl/libxl_driver.c    |  58 +++++++++-
>  src/libxl/libxl_migration.c | 275 +++++++++++++++++++++++++++++++++++++++++---
>  src/libxl/libxl_migration.h |   9 ++
>  3 files changed, 325 insertions(+), 17 deletions(-)
> 
> diff --git a/src/libxl/libxl_driver.c b/src/libxl/libxl_driver.c
> index 74cb05a..e5b8f48 100644
> --- a/src/libxl/libxl_driver.c
> +++ b/src/libxl/libxl_driver.c
> @@ -5934,6 +5934,61 @@ libxlDomainMigrateBegin3Params(virDomainPtr domain,
>  }
>  
>  static int
> +libxlDomainMigratePrepareTunnel3Params(virConnectPtr dconn,
> +                                       virStreamPtr st,
> +                                       virTypedParameterPtr params,
> +                                       int nparams,
> +                                       const char *cookiein,
> +                                       int cookieinlen,
> +                                       char **cookieout ATTRIBUTE_UNUSED,
> +                                       int *cookieoutlen ATTRIBUTE_UNUSED,
> +                                       unsigned int flags)
> +{
> +    libxlDriverPrivatePtr driver = dconn->privateData;
> +    virDomainDefPtr def = NULL;
> +    const char *dom_xml = NULL;
> +    const char *dname = NULL;
> +    const char *uri_in = NULL;
> +
> +#ifdef LIBXL_HAVE_NO_SUSPEND_RESUME
> +    virReportUnsupportedError();
> +    return -1;
> +#endif
> +
> +    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 (virDomainMigratePrepareTunnel3ParamsEnsureACL(dconn, def) < 0)
> +        goto error;
> +
> +    if (libxlDomainMigrationPrepareTunnel3(dconn, st, &def, cookiein,
> +                                           cookieinlen, flags) < 0)
> +        goto error;
> +
> +    return 0;
> +
> + error:
> +    virDomainDefFree(def);
> +    return -1;
> +}
> +
> +static int
>  libxlDomainMigratePrepare3Params(virConnectPtr dconn,
>                                   virTypedParameterPtr params,
>                                   int nparams,
> @@ -6033,7 +6088,7 @@ libxlDomainMigratePerform3Params(virDomainPtr dom,
>      if (virDomainMigratePerform3ParamsEnsureACL(dom->conn, vm->def) < 0)
>          goto cleanup;
>  
> -    if (flags & VIR_MIGRATE_PEER2PEER) {
> +    if ((flags & (VIR_MIGRATE_TUNNELLED | VIR_MIGRATE_PEER2PEER))) {
>          if (libxlDomainMigrationPerformP2P(driver, vm, dom->conn, dom_xml,
>                                             dconnuri, uri, dname, flags) < 0)
>              goto cleanup;
> @@ -6518,6 +6573,7 @@ static virHypervisorDriver libxlHypervisorDriver = {
>      .nodeDeviceReset = libxlNodeDeviceReset, /* 1.2.3 */
>      .domainMigrateBegin3Params = libxlDomainMigrateBegin3Params, /* 1.2.6 */
>      .domainMigratePrepare3Params = libxlDomainMigratePrepare3Params, /* 1.2.6 */
> +    .domainMigratePrepareTunnel3Params = libxlDomainMigratePrepareTunnel3Params, /* 3.1.0 */
>      .domainMigratePerform3Params = libxlDomainMigratePerform3Params, /* 1.2.6 */
>      .domainMigrateFinish3Params = libxlDomainMigrateFinish3Params, /* 1.2.6 */
>      .domainMigrateConfirm3Params = libxlDomainMigrateConfirm3Params, /* 1.2.6 */
> diff --git a/src/libxl/libxl_migration.c b/src/libxl/libxl_migration.c
> index 7beabd2..6bd8983 100644
> --- a/src/libxl/libxl_migration.c
> +++ b/src/libxl/libxl_migration.c
> @@ -44,6 +44,7 @@
>  #include "libxl_migration.h"
>  #include "locking/domain_lock.h"
>  #include "virtypedparam.h"
> +#include "fdstream.h"
>  
>  #define VIR_FROM_THIS VIR_FROM_LIBXL
>  
> @@ -554,6 +555,95 @@ libxlDomainMigrationPrepareAny(virConnectPtr dconn,
>  }
>  
>  int
> +libxlDomainMigrationPrepareTunnel3(virConnectPtr dconn,
> +                                   virStreamPtr st,
> +                                   virDomainDefPtr *def,
> +                                   const char *cookiein,
> +                                   int cookieinlen,
> +                                   unsigned int flags)
> +{
> +    libxlMigrationCookiePtr mig = NULL;
> +    libxlDriverPrivatePtr driver = dconn->privateData;
> +    virDomainObjPtr vm = NULL;
> +    libxlMigrationDstArgs *args = NULL;
> +    virThread thread;
> +    bool taint_hook = false;
> +    libxlDomainObjPrivatePtr priv = NULL;
> +    char *xmlout = NULL;
> +    int dataFD[2] = { -1, -1 };
> +    int ret = -1;
> +
> +    if (libxlDomainMigrationPrepareAny(dconn, def, cookiein, cookieinlen,
> +                                       &mig, &xmlout, &taint_hook) < 0)
> +        goto error;
> +
> +    if (!(vm = virDomainObjListAdd(driver->domains, *def,
> +                                   driver->xmlopt,
> +                                   VIR_DOMAIN_OBJ_LIST_ADD_LIVE |
> +                                   VIR_DOMAIN_OBJ_LIST_ADD_CHECK_LIVE,
> +                                   NULL)))
> +        goto error;
> +
> +    *def = NULL;
> +    priv = vm->privateData;
> +
> +    if (taint_hook) {
> +        /* Domain XML has been altered by a hook script. */
> +        priv->hookRun = true;
> +    }
> +
> +    /*
> +     * The data flow of tunnel3 migration in the dest side:
> +     * stream -> pipe -> recvfd of libxlDomainStartRestore
> +     */
> +    if (pipe(dataFD) < 0)
> +        goto error;
> +
> +    /* Stream data will be written to pipeIn */
> +    if (virFDStreamOpen(st, dataFD[1]) < 0)
> +        goto error;
> +    dataFD[1] = -1; /* 'st' owns the FD now & will close it */
> +
> +    if (libxlMigrationDstArgsInitialize() < 0)
> +        goto error;
> +
> +    if (!(args = virObjectNew(libxlMigrationDstArgsClass)))
> +        goto error;
> +
> +    args->conn = dconn;
> +    args->vm = vm;
> +    args->flags = flags;
> +    args->migcookie = mig;
> +    /* Receive from pipeOut */
> +    args->recvfd = dataFD[0];
> +    args->nsocks = 0;
> +    if (virThreadCreate(&thread, false, libxlDoMigrateReceive, args) < 0) {
> +        virReportError(VIR_ERR_OPERATION_FAILED, "%s",
> +                       _("Failed to create thread for receiving migration data"));
> +        goto error;
> +    }
> +
> +    ret = 0;
> +    goto done;
> +
> + error:
> +    VIR_FORCE_CLOSE(dataFD[1]);
> +    VIR_FORCE_CLOSE(dataFD[0]);
> +    virObjectUnref(args);
> +    /* Remove virDomainObj from domain list */
> +    if (vm) {
> +        virDomainObjListRemove(driver->domains, vm);
> +        vm = NULL;
> +    }
> +
> + done:
> +    if (vm)
> +        virObjectUnlock(vm);
> +
> +    return ret;
> +}
> +
> +int
>  libxlDomainMigrationPrepare(virConnectPtr dconn,
>                              virDomainDefPtr *def,
>                              const char *uri_in,
> @@ -734,9 +824,143 @@ 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.
> +typedef struct _libxlTunnelMigrationThread libxlTunnelMigrationThread;
> +struct _libxlTunnelMigrationThread {
> +    virStreamPtr st;
> +    int srcFD;
> +};
> +#define TUNNEL_SEND_BUF_SIZE 65536
> +
> +/*
> + * The data flow of tunnel3 migration in the src side:
> + * libxlDoMigrateSend() -> pipe
> + * libxlTunnel3MigrationFunc() polls pipe out and then write to dest stream.
> + */
> +static void libxlTunnel3MigrationFunc(void *arg)
> +{
> +    libxlTunnelMigrationThread *data = (libxlTunnelMigrationThread *)arg;
> +    char *buffer = NULL;
> +    struct pollfd fds[1];
> +    int timeout = -1;
> +
> +    if (VIR_ALLOC_N(buffer, TUNNEL_SEND_BUF_SIZE) < 0)
> +        return;
> +
> +    fds[0].fd = data->srcFD;
> +    for (;;) {
> +        int ret;
> +
> +        fds[0].events = POLLIN;
> +        fds[0].revents = 0;
> +        ret = poll(fds, ARRAY_CARDINALITY(fds), timeout);
> +        if (ret < 0) {
> +            if (errno == EAGAIN || errno == EINTR)
> +                continue;
> +            virReportError(errno, "%s",
> +                           _("poll failed in libxlTunnel3MigrationFunc"));
> +            goto cleanup;
> +        }
> +
> +        if (ret == 0) {
> +            VIR_DEBUG("poll returned 0");
> +            break;
> +        }
> +
> +        if (fds[0].revents & (POLLIN | POLLERR | POLLHUP)) {
> +            int nbytes;
> +
> +            nbytes = read(data->srcFD, buffer, TUNNEL_SEND_BUF_SIZE);
> +            if (nbytes > 0) {
> +                /* Write to dest stream */
> +                if (virStreamSend(data->st, buffer, nbytes) < 0) {
> +                    virStreamAbort(data->st);
> +                    goto cleanup;
> +                }
> +            } else if (nbytes < 0) {
> +                virReportError(errno, "%s",
> +                               _("tunnelled migration failed to read from xen side"));
> +                    virStreamAbort(data->st);
> +                    goto cleanup;
This is here since v1 and went unnoticed (in make syntax-check too), but the
indentation is off here. It should be 4 spaces to the left. But hopefully that
could be adjusted upon commit if no more comments are brought up?

> +            } else {
> +                /* EOF; transferred all data */
> +                break;
> +            }
> +        }
> +    }
> +
> +    ignore_value(virStreamFinish(data->st));
> +
> + cleanup:
> +    VIR_FREE(buffer);
> +
> +    return;
> +}
> +
> +struct libxlTunnelControl {
> +    libxlTunnelMigrationThread tmThread;
> +    virThread thread;
> +    int dataFD[2];
> +};
> +
> +static int
> +libxlMigrationStartTunnel(libxlDriverPrivatePtr driver,
> +                          virDomainObjPtr vm,
> +                          unsigned long flags,
> +                          virStreamPtr st,
> +                          struct libxlTunnelControl *tc)
> +{
> +    libxlTunnelMigrationThread *arg = NULL;
> +    int ret = -1;
> +
> +    if (VIR_ALLOC(tc) < 0)
> +        goto out;
> +
> +    tc->dataFD[0] = -1;
> +    tc->dataFD[1] = -1;
> +    if (pipe(tc->dataFD) < 0) {
> +        virReportError(errno, "%s", _("Unable to make pipes"));
> +        goto out;
> +    }
> +
> +    arg = &tc->tmThread;
> +    /* Read from pipe */
> +    arg->srcFD = tc->dataFD[0];
> +    /* Write to dest stream */
> +    arg->st = st;
> +    if (virThreadCreate(&tc->thread, true,
> +                        libxlTunnel3MigrationFunc, arg) < 0) {
> +        virReportError(errno, "%s",
> +                       _("Unable to create tunnel migration thread"));
> +        goto out;
> +    }
> +
> +    virObjectUnlock(vm);
> +    /* Send data to pipe */
> +    ret = libxlDoMigrateSend(driver, vm, flags, tc->dataFD[1]);
> +    virObjectLock(vm);
> +
> + out:
> +    /* libxlMigrationStopTunnel will be called in libxlDoMigrateP2P to free
> +     * all resources for us. */
> +    return ret;
> +}
> +
> +static void libxlMigrationStopTunnel(struct libxlTunnelControl *tc)
> +{
> +    if (!tc)
> +        return;
> +
> +    virThreadCancel(&tc->thread);
> +    virThreadJoin(&tc->thread);
> +
> +    VIR_FORCE_CLOSE(tc->dataFD[0]);
> +    VIR_FORCE_CLOSE(tc->dataFD[1]);
> +    VIR_FREE(tc);
> +}
> +
> +/* This function is a simplification of virDomainMigrateVersion3Full and
> + * restricting it to migration v3 with params since it was the first to be
> + * introduced in libxl.
>   */
>  static int
>  libxlDoMigrateP2P(libxlDriverPrivatePtr driver,
> @@ -761,6 +985,9 @@ libxlDoMigrateP2P(libxlDriverPrivatePtr driver,
>      bool cancelled = true;
>      virErrorPtr orig_err = NULL;
>      int ret = -1;
> +    /* For tunnel migration */
> +    virStreamPtr st = NULL;
> +    struct libxlTunnelControl *tc = NULL;
>  
>      dom_xml = libxlDomainMigrationBegin(sconn, vm, xmlin,
>                                          &cookieout, &cookieoutlen);
> @@ -788,29 +1015,40 @@ libxlDoMigrateP2P(libxlDriverPrivatePtr driver,
>  
>      VIR_DEBUG("Prepare3");
>      virObjectUnlock(vm);
> -    ret = dconn->driver->domainMigratePrepare3Params
> -        (dconn, params, nparams, cookieout, cookieoutlen, NULL, NULL, &uri_out, destflags);
> +    if (flags & VIR_MIGRATE_TUNNELLED) {
> +        if (!(st = virStreamNew(dconn, 0)))
> +            goto cleanup;
> +        ret = dconn->driver->domainMigratePrepareTunnel3Params
> +            (dconn, st, params, nparams, cookieout, cookieoutlen, NULL, NULL, destflags);
> +    } else {
> +        ret = dconn->driver->domainMigratePrepare3Params
> +            (dconn, params, nparams, cookieout, cookieoutlen, NULL, NULL, &uri_out, destflags);
> +    }
>      virObjectLock(vm);
>  
>      if (ret == -1)
>          goto cleanup;
>  
> -    if (uri_out) {
> -        if (virTypedParamsReplaceString(&params, &nparams,
> -                                        VIR_MIGRATE_PARAM_URI, uri_out) < 0) {
> -            orig_err = virSaveLastError();
> +    if (!(flags & VIR_MIGRATE_TUNNELLED)) {
> +        if (uri_out) {
> +            if (virTypedParamsReplaceString(&params, &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;
>          }
> -    } 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 (flags & VIR_MIGRATE_TUNNELLED)
> +        ret = libxlMigrationStartTunnel(driver, vm, flags, st, tc);
> +    else
> +        ret = libxlDomainMigrationPerform(driver, vm, NULL, NULL,
> +                                          uri_out, NULL, flags);
>      if (ret < 0)
>          orig_err = virSaveLastError();
>  
> @@ -848,6 +1086,11 @@ libxlDoMigrateP2P(libxlDriverPrivatePtr driver,
>                   vm->def->name);
>  
>   cleanup:
> +    if (flags & VIR_MIGRATE_TUNNELLED) {
> +        libxlMigrationStopTunnel(tc);
> +        virObjectUnref(st);
> +    }
> +
>      if (ddomain) {
>          virObjectUnref(ddomain);
>          ret = 0;
> diff --git a/src/libxl/libxl_migration.h b/src/libxl/libxl_migration.h
> index 8a074a0..fcea558 100644
> --- a/src/libxl/libxl_migration.h
> +++ b/src/libxl/libxl_migration.h
> @@ -29,6 +29,7 @@
>  # define LIBXL_MIGRATION_FLAGS                  \
>      (VIR_MIGRATE_LIVE |                         \
>       VIR_MIGRATE_PEER2PEER |                    \
> +     VIR_MIGRATE_TUNNELLED |                    \
>       VIR_MIGRATE_PERSIST_DEST |                 \
>       VIR_MIGRATE_UNDEFINE_SOURCE |              \
>       VIR_MIGRATE_PAUSED)
> @@ -53,6 +54,14 @@ libxlDomainMigrationPrepareDef(libxlDriverPrivatePtr driver,
>                                 const char *dname);
>  
>  int
> +libxlDomainMigrationPrepareTunnel3(virConnectPtr dconn,
> +                                   virStreamPtr st,
> +                                   virDomainDefPtr *def,
> +                                   const char *cookiein,
> +                                   int cookieinlen,
> +                                   unsigned int flags);
> +
> +int
>  libxlDomainMigrationPrepare(virConnectPtr dconn,
>                              virDomainDefPtr *def,
>                              const char *uri_in,
> 


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