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author | Daniel P. Berrange <berrange@redhat.com> | 2010-11-02 12:43:44 +0000 |
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committer | Daniel P. Berrange <berrange@redhat.com> | 2011-05-16 15:09:19 +0100 |
commit | 65043d2dffa6529c9dcc6f8e0808ce1d4d504e6f (patch) | |
tree | e98bf30545ec63b3b64d691525481aacb015ebb3 /src/libvirt_internal.h | |
parent | Automatically generate the hvsupport.html.in file from source files (diff) | |
download | libvirt-65043d2dffa6529c9dcc6f8e0808ce1d4d504e6f.tar.gz libvirt-65043d2dffa6529c9dcc6f8e0808ce1d4d504e6f.tar.bz2 libvirt-65043d2dffa6529c9dcc6f8e0808ce1d4d504e6f.zip |
Introduce yet another migration version in API.
Migration just seems to go from bad to worse. We already had to
introduce a second migration protocol when adding the QEMU driver,
since the one from Xen was insufficiently flexible to cope with
passing the data the QEMU driver required.
It turns out that this protocol still has some flaws that we
need to address. The current sequence is
* Src: DumpXML
- Generate XML 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
- Kill off VM if successful, resume if failed
* Dst: Finish
- Wait for recv completion and check status
- Kill off VM if unsuccessful
The problems with this are:
- Since the first step is a generic 'DumpXML' call, we can't
add in other migration specific data. eg, we can't include
any VM lease data from lock manager plugins
- Since the first step is a generic 'DumpXML' call, we can't
emit any 'migration begin' event on the source, or have
any hook that runs right at the start of the process
- Since there is no final step on the source, if the Finish
method fails to receive all migration data & has to kill
the VM, then there's no way to resume the original VM
on the source
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.
Diffstat (limited to 'src/libvirt_internal.h')
-rw-r--r-- | src/libvirt_internal.h | 66 |
1 files changed, 66 insertions, 0 deletions
diff --git a/src/libvirt_internal.h b/src/libvirt_internal.h index 1c4fa4f24..81d0c56e9 100644 --- a/src/libvirt_internal.h +++ b/src/libvirt_internal.h @@ -66,6 +66,13 @@ enum { * perform step is used. */ VIR_DRV_FEATURE_MIGRATION_DIRECT = 5, + + /* + * Driver supports V3-style virDomainMigrate, ie domainMigrateBegin3/ + * domainMigratePrepare3/domainMigratePerform3/domainMigrateFinish3/ + * domainMigrateConfirm3. + */ + VIR_DRV_FEATURE_MIGRATION_V3 = 6, }; @@ -115,4 +122,63 @@ int virDomainMigratePrepareTunnel(virConnectPtr dconn, unsigned long resource, const char *dom_xml); + +char *virDomainMigrateBegin3(virDomainPtr domain, + char **cookieout, + int *cookieoutlen, + unsigned long flags, + const char *dname, + unsigned long resource); + +int virDomainMigratePrepare3(virConnectPtr dconn, + const char *cookiein, + int cookieinlen, + char **cookieout, + int *cookieoutlen, + const char *uri_in, + char **uri_out, + unsigned long flags, + const char *dname, + unsigned long resource, + const char *dom_xml); + +int virDomainMigratePrepareTunnel3(virConnectPtr dconn, + virStreamPtr st, + const char *cookiein, + int cookieinlen, + char **cookieout, + int *cookieoutlen, + unsigned long flags, + const char *dname, + unsigned long resource, + const char *dom_xml); + + +int virDomainMigratePerform3(virDomainPtr dom, + const char *cookiein, + int cookieinlen, + char **cookieout, + int *cookieoutlen, + const char *uri, + unsigned long flags, + const char *dname, + unsigned long resource); + +int virDomainMigrateFinish3(virConnectPtr dconn, + const char *dname, + const char *cookiein, + int cookieinlen, + char **cookieout, + int *cookieoutlen, + const char *uri, + unsigned long flags, + int cancelled, /* Kill the dst VM */ + virDomainPtr *newdom); + +int virDomainMigrateConfirm3(virDomainPtr domain, + const char *cookiein, + int cookieinlen, + unsigned long flags, + int restart); /* Restart the src VM */ + #endif |