Current QAPI 'migrate' command design (for initiating a migration
stream) contains information regarding different migrate transport mechanism
(tcp / unix / exec), dest-host IP address, and binding port number in form of
a string. Thus the design does seem to have some design issues. Some of the
issues, stated below are:
1. Use of string URIs is a data encoding scheme within a data encoding scheme.
QEMU code should directly be able to work with the results from QAPI,
without resorting to do a second level of parsing (eg. socket_parse()).
2. For features / parameters related to migration, the migration tunables needs
to be defined and updated upfront. For example, 'migrate-set-capability'
and 'migrate-set-parameter' is required to enable multifd capability and
multifd-number of channels respectively. Instead, 'Multifd-channels' can
directly be represented as a single additional parameter to 'migrate'
QAPI. 'migrate-set-capability' and 'migrate-set-parameter' commands could
be used for runtime tunables that need setting after migration has already
started.
The current patchset focuses on solving the first problem of multi-level
encoding of URIs. The patch defines 'migrate' command as a QAPI discriminated
union for the various transport backends (like socket, exec and rdma), and on
basis of transport backends, different migration parameters are defined.
(uri) string --> (channel) Channel-type
Transport-type
Migration parameters based on transport type
-----------------------------------------------------------------------------
Author Het Gala (5):
migration: Updated QAPI format for 'migrate' qemu monitor command
migration: HMP side changes for modified 'migrate' QAPI design
migration: Avoid multiple parsing of uri in migration code flow
migration: Modified 'migrate-incoming' QAPI and HMP side changes on
the destination interface.
migration: Established connection for listener sockets on the dest
interface
migration/migration.c | 133 +++++++++++++++++++++++++++++----------
migration/socket.c | 31 +--------
migration/socket.h | 5 +-
monitor/hmp-cmds.c | 101 ++++++++++++++++++++++++++++-
qapi/migration.json | 143 ++++++++++++++++++++++++++++++++++++++++--
softmmu/vl.c | 2 +-
6 files changed, 344 insertions(+), 71 deletions(-)
--
2.22.3
