On Thu, Feb 09, 2023 at 06:41:41PM +0530, Het Gala wrote: > > On 09/02/23 3:59 pm, Daniel P. Berrangé wrote: > > On Wed, Feb 08, 2023 at 09:35:56AM +0000, Het Gala wrote: > > > Existing 'migrate' QAPI design enforces transport mechanism, ip address > > > of destination interface and corresponding port number in the form > > > of a unified string 'uri' parameter for initiating a migration stream. > > > This scheme has a significant flaw in it - double encoding of existing > > > URIs to extract migration info. > > > > > > The current patch maps QAPI uri design onto well defined MigrateChannel > > > struct. This modified QAPI helps in preventing multi-level uri > > > encodings ('uri' parameter is kept for backward compatibility). > > > > > > Suggested-by: Daniel P. Berrange <berra...@redhat.com> > > > Suggested-by: Manish Mishra <manish.mis...@nutanix.com> > > > Suggested-by: Aravind Retnakaran <aravind.retnaka...@nutanix.com> > > > Signed-off-by: Het Gala <het.g...@nutanix.com> > > > --- > > > qapi/migration.json | 131 +++++++++++++++++++++++++++++++++++++++++++- > > > 1 file changed, 129 insertions(+), 2 deletions(-) > > > > > > diff --git a/qapi/migration.json b/qapi/migration.json > > > index c84fa10e86..79acfcfe4e 100644 > > > --- a/qapi/migration.json > > > +++ b/qapi/migration.json > > > @@ -1449,12 +1449,108 @@ > > > ## > > > { 'command': 'migrate-continue', 'data': {'state': 'MigrationStatus'} } > > > + > > > +## > > > +# @MigrateSocketAddr: > > > +# > > > +# To support different type of socket. > > > +# > > > +# @socket-type: Different type of socket connections. > > > +# > > > +# Since 8.0 > > > +## > > > +{ 'struct': 'MigrateSocketAddr', > > > + 'data': {'socket-type': 'SocketAddress' } } > > I'd really like this struct to go away, but if it must exist, > > then call this field 'addr', as I think 'socket-type' is overly > > verbose. > In v3 patchset, I have already changed from 'socket-type' to 'data'.
> > > + > > > +## > > > +# @MigrateExecAddr: > > > + # > > > + # Since 8.0 > > > + ## > > > +{ 'struct': 'MigrateExecAddr', > > > + 'data' : {'data': ['str'] } } > > Instead of having the field called 'data' lets me more > > descriptive, and perhaps rename the struct too: > > > > { 'struct': 'MigrateCommand', > > 'data' : {'args': ['str'] } } > > > > Any thoughts on whether we should allow for setting env varibles > > too ? > > Daniel, won't 'MigrateCommand' be too generic ? I am of the opinion that, if > its related to 'exec' transport, the struct name should reflect that ? Mostly I'm indicating that it is not really an address that we're providing, it is a command argv, so felt the struct could reflect that. We could do MigrateExecCommand. > I did not get your question allowing setting environment variables. Could > you explain it in more detail ? When spawning processes, execvp() lets use provide argv + env. If env is not provided, we inherit from QEMU. Currently we're only providing argv, so I was wondering if we should allow env too. Probably overkill, but at least having the 'MigrateCommand' struct lets us add it later. > > > > +## > > > +# @MigrateRdmaAddr: > > > +# > > > +# Since 8.0 > > > +## > > > +{ 'struct': 'MigrateRdmaAddr', > > > + 'data' : {'data': 'InetSocketAddress' } } > > InetSocketAddress is a plain struct, so I think we can use > > that directly, no ? > Yes, we can use it directly. Just to keep consistency with other transport > mechanisms, I made a separate struct even for rdma. > > > + > > > +## > > > +# @MigrateAddress: > > > +# > > > +# The options available for communication transport mechanisms for > > > migration > > > +# > > > +# Since 8.0 > > > +## > > > +{ 'union' : 'MigrateAddress', > > > + 'base' : { 'transport' : 'MigrateTransport'}, > > > + 'discriminator' : 'transport', > > > + 'data' : { > > > + 'socket' : 'MigrateSocketAddr', > > > + 'exec' : 'MigrateExecAddr', > > > + 'rdma': 'MigrateRdmaAddr' } } > > Ideally this would be > > > > 'data' : { > > 'socket' : 'SocketAddress', > > 'exec' : 'MigrateCommand', > > 'rdma': 'InetSocketAddress' } } > > > > though the first SocketAddress isn't possible unless it is easy to > > lift the QAPI limitation. > > Yes, I agree with you Daniel. If we can fix the first one - SocketAddress > one, can we also allow ['str'] to also be directly represented by modifying > QAPI ? > > ex: 'exec': ['str'] ... something like this ? No, I think it is important to use a struct for 'exec' to allow future expansion of parameters. > > > +# -> { "execute": "migrate", > > > +# "arguments": { > > > +# "channel": { "channeltype": "main", > > > +# "addr": { "transport": "socket", > > > +# "socket-type": { "type': "inet', > > > +# "host": "10.12.34.9", > > > +# "port": "1050" } } } > > > } } > > > +# <- { "return": {} } > > > +# > > > +# -> { "execute": "migrate", > > > +# "arguments": { > > > +# "channel": { "channeltype": "main", > > > +# "addr": { "transport": "exec", > > > +# "exec": ["/bin/nc", "-U", > > > +# "/some/sock" ] } } } } > > > +# <- { "return": {} } > > > +# > > > +# -> { "execute": "migrate", > > > +# "arguments": { > > > +# "channel": { "channeltype": "main", > > > +# "addr": { "transport": "rdma", > > > +# "rdma": { "host": "10.12.34.9", > > > +# "port": "1050" } } } } } > > > +# <- { "return": {} } > > > +# > > > ## > > > { 'command': 'migrate', > > > - 'data': {'uri': 'str', '*blk': 'bool', '*inc': 'bool', > > > - '*detach': 'bool', '*resume': 'bool' } } > > > + 'data': {'*uri': 'str', '*channel': 'MigrateChannel', '*blk': 'bool', > > > + '*inc': 'bool', '*detach': 'bool', '*resume': 'bool' } } > > IIRC, the intention was to allow multiple channels to be set in a > > follow up to this series. If so that would require adding yet another > > field as an array of MigrateChannel. Should we just go for the > > array straight away, and just limit it to 1 element as a runtime > > check ? eg > > > > 'data': {'*uri': 'str', '*channels': ['MigrateChannel'], '*blk': 'bool', > > '*inc': 'bool', '*detach': 'bool', '*resume': 'bool' } } > Yes, I got your point Daniel. But I feel it is better to introduce it in > follow up series along with introducing different channel types (main, data, > postcopy). It would then also make sense to introduce a list of > 'MigrateChannel'. Right, that means if we release QEMU 8.0.0 with the 'channel' parameter, and your next series doesn't get merged until 8.1.0, we're stuck supporting both 'channel' and 'channels'. With regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|