dkodihal at linux.vnet.ibm.com
Sat Feb 3 19:08:47 AEDT 2018
On 03/02/18 2:40 am, Vernon Mauery wrote:
> On 02-Feb-2018 11:18 AM, Andrew Jeffery wrote:
>> Hi Deepak,
>>> So several of the existing OpenBMC apps implement specific D-Bus
>>> services. What does it take to make remote D-Bus calls to such apps?
>>> - It doesn't look like the D-Bus spec or libdbus officially has anything
>>> for D-Bus across computers. There are some good notes at
>> Applications can cannect to remote dbus servers; the --address option
>> to dbus-daemon allows it to listen on a TCP socket and setting
>> DBUS_SESSION_BUS_ADDRESS will point applications in the right
>> direction. So there are probably two ways we could do this:
> Putting DBus on an externally-available TCP socket is a security
> architect's nightmare. All command and control of the entire BMC is done
> over DBus; we cannot put that on an externally-available address. I
> suppose if you have an internal connection and switching fabric between
> the nodes, this would be possible.
This shouldn't be a problem though with SSH forwarding, with a proxy
D-Bus daemon for example.
https://www.freedesktop.org/wiki/Software/DBusRemote/ talks about
another issue with SSH forwarding D-Bus, which I haven't fully
understood. I know that the Gabriel project took the SSH forwarding route.
>> 1. Slave BMCs connect to the master's DBus daemon, and applications
>> namespace their objects appropriately. Multi-BMC aware applications on
>> the master access the namespaced objects as required
>> 2. Slave BMCs are willfully ignorant of their role, with the master
>> connecting to the slaves' DBus daemons to form a coherent global view
>> of the bus for its multi-BMC aware applications, which access the
>> remote objects as required.
>> Given the support DBus has today it might be easier to go for 1 than
>> for 2, if we go down this path at all.
>>  https://dbus.freedesktop.org/doc/dbus-daemon.1.html
>>> - There are ways to achieve this via Qt D-Bus, but it would involve some
>>> amount tweaking with the D-Bus configs.
>>> - I'm not aware of any open/active project implementing remote D-Bus.
>> Here is someone's attempt at making it easier:
>> http://gabriel.sourceforge.net/howto.html though you would struggle to
>> say it's active given the last contribution was 2013-05-14.
>>> - Thoughts on doing remote D-Bus over WebSockets?
>> How do websockets come into the picture? Why do we need the extra
>> complication vs normal sockets?
More information about the openbmc