SOL Logging

Stewart Smith stewart at
Mon Sep 10 16:52:46 AEST 2018

Ed Tanous <ed.tanous at> writes:
> On 09/04/2018 05:07 PM, Emily Shaffer wrote:
>> I wonder if there's a different and more useful way we can provide the 
>> console scrollback. Thinking about this, it's not just a GUI issue, 
>> right - we deliver our console over TCP to a client elsewhere and would 
>> have the same dedupe issues if we needed to start providing backlog.  
> Correct, this isn't _just_ a webui issue.  It happens on all the 
> available interfaces (SSH, HTML5, and obmc-console-client)
>> Speaking with almost no experience implementing server-side sockets, is 
>> it possible for us to keep that ring buffer in the console socket as well?
> obmc-console already keeps a ring-buffer style log of all the previous 
> characters.  The easiest to implement answer, which is probably good 
> enough for most cases, would be to simply make obmc-console barf up the 
> saved console log ring buffer when any new client connects.  This will 
> have problems if your control characters have run off the end of the 
> buffer, and the console would appear to quickly replay your last X 
> characters worth of interactions, which isn't desired.
> I could also imagine a case where this isn't the desired behavior if 
> you're using automation to interact with SSH/SOL, so it might need to be 
> selectable by the client or have some kind of reasonable workaround.

Yeah, if we got some random amount of previous console text over IPMI
SoL or SSH host console, I can imagine that all my CI scripts would
pretty spectacularly blow up.

For the Web UI though, I can see that keeping something like a tmux
session would be good though.
Stewart Smith
OPAL Architect, IBM.

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