Re: [libvirt] [PATCH 02/16] Introduce yet another migration version in API.

Migration just seems togo from bad to worse. We already had to

This patch attempts to introduce a version 3 that uses the improved 5 step sequence * Src: Begin - Generate XML to pass to dst - Generate optional cookie to pass to dst * Dst: Prepare - Get ready to accept incoming VM - Generate optional cookie to pass to src * Src: Perform - Start migration and wait for send completion - Generate optional cookie to pass to dst * Dst: Finish - Wait for recv completion and check status - Kill off VM if failed, resume if success - Generate optional cookie to pass to src * Src: Confirm - Kill off VM if success, resume if failed

The API is designed to allow both input and output cookies in all methods where applicable. This lets us pass around arbitrary extra driver specific data between src & dst during migration. Combined with the extra 'Begin' method this lets us pass lease information from source to dst at the start of migration Moving the killing of the source VM out of Perform and into Confirm, means we can now recover if the dst host can't successfully Finish receiving migration data.

+ * Src: Begin + * - Generate XML to pass to dst + * - Generate optional cookie to pass to dst + * + * Dst: Prepare + * - Get ready to accept incoming VM + * - Generate optional cookie to pass to src + * + * Src: Perform + * - Start migration and wait for send completion + * - Generate optional cookie to pass to dst + * + * Dst: Finish + * - Wait for recv completion and check status + * - Kill off VM if failed, resume if success + * - Generate optional cookie to pass to src + * + * Src: Confirm + * - Kill off VM if success, resume if failed + * + */ +/* + * Not for public use. This function is part of the internal + * implementation of migration in the remote case. + */ +char * +virDomainMigrateBegin3(virDomainPtr domain, + char **cookieout, + int *cookieoutlen, + unsigned long flags, + const char *dname, + unsigned long bandwidth) +{ + virConnectPtr conn; + + VIR_DOMAIN_DEBUG(domain, "cookieout=%p, cookieoutlen=%p, " + "flags=%lu, dname=%s, bandwidth=%lu", + cookieout, cookieoutlen, flags, + NULLSTR(dname), bandwidth); + + virResetLastError(); + + if (!VIR_IS_CONNECTED_DOMAIN (domain)) {

+++ b/src/libvirt_private.syms @@ -547,6 +547,12 @@ virDomainMigratePerform; virDomainMigratePrepare2; virDomainMigratePrepare; virDomainMigratePrepareTunnel; +virDomainMigrateBegin3; +virDomainMigratePrepare3; +virDomainMigratePrepareTunnel3; +virDomainMigratePerform3; +virDomainMigrateFinish3; +virDomainMigrateConfirm3;