BMC redundancy

[Ratan Gupta]

Hi Andrew,


On Friday 02 February 2018 06:18 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
>> https://www.freedesktop.org/wiki/Software/DBusRemote/.
> 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:
>
> 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.
>
> [1] 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.
How it would be beneficial sending dbus packets over ssh v/s current 
REST architecture,where url is mapped with the Dbus objects?
>
>> - 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?
>
> Cheers,
>
> Andrew
>
Regards
Ratan