Re: [libvirt PATCH 8/9] qemu: Allow migration over UNIX socket

On Tue, Aug 25, 2020 at 17:12:59 +0100, Daniel P. Berrangé wrote: > On Tue, Aug 25, 2020 at 05:53:32PM +0200, Jiri Denemark wrote: > > On Tue, Aug 25, 2020 at 07:47:14 +0200, Martin Kletzander wrote: > > > - /* RDMA and multi-fd migration requires QEMU to connect to the destination > > > - * itself. > > > - */ > > > - if (STREQ(uribits->scheme, "rdma") || (flags & VIR_MIGRATE_PARALLEL)) > > > - spec.destType = MIGRATION_DEST_HOST; > > > - else > > > - spec.destType = MIGRATION_DEST_CONNECT_HOST; > > > - spec.dest.host.protocol = uribits->scheme; > > > - spec.dest.host.name = uribits->server; > > > - spec.dest.host.port = uribits->port; > > > + if (STREQ(uribits->scheme, "unix")) { > > > + if (flags & VIR_MIGRATE_TLS) { > > > + virReportError(VIR_ERR_OPERATION_UNSUPPORTED, "%s", > > > + _("Migration over UNIX socket with TLS is not supported")); > > > + return -1; > > > + } > > > + if (flags & VIR_MIGRATE_PARALLEL) { > > > + virReportError(VIR_ERR_OPERATION_UNSUPPORTED, "%s", > > > + _("Parallel migration over UNIX socket is not supported")); > > > + return -1; > > > + } > > > > Is there a reason for not supporting TLS and multi-fd with unix sockets? > > >From libvirt's POV this should be fairly trivial (can be a follow-up > > patch, though): introduce MIGRATION_DEST_SOCKET in addition to > > MIGRATION_DEST_CONNECT_SOCKET and use it to instruct QEMU to connect > > using unix: URI (unless this support was removed from QEMU). > > multi-fd is certainly desirable to support and I don't see any reason > to block that. > > TLS is more problematic, at least if you are using x509 credentials then > you need to tell QEMU what hostname to use for validation. This would > require us to accept a hostname parameter in the URI giving the UNIX > socket. We already support this generally regardless on the transport via VIR_MIGRATE_PARAM_TLS_DESTINATION parameter.