[lttng-dev] lttng-relayd---->lttng-relayd communication

[Jonathan Rajotte-Julien]

Hi,

On Sat, Feb 03, 2018 at 05:08:25AM +0000, Ramith Shetty wrote:
> 
> If we have a setup as below. Can we stream the logs to host SystemA  from TargetB below?
> 
> Here TargetA and TargetB are part of a private network. Only TargetA has connectivity to SystemA. We need to stream data from TargetB to SystemA.
> 
> [    TargetB----->TargetA    ]------->[SystemA]

This seems like a perfect match for ssh tunneling via TargetA.

On System A:
    Start lttng-relayd.
      The default ports are as follow:
        Control port: tcp://0.0.0.0:5342
        Data port: tcp://0.0.0.0:5343
        Live port: tcp://localhost:5344

On Target B:
    Create a ssh tunnel via Target A:
      ssh -nNT -L 9990:SystemA:5342 -L 9991:SystemA:5343 targetA

    Setup live session correctly:
      lttng create --set-url net://localhost:9990:9991 --live
      lttng ...

At that point you should be able to attach locally a babeltrace to SystemA.
Note that the ssh tunnel needs to be up for everything to work. It might require
some adjustment depending on your network configuration etc.

I tested it locally with 3 VMs and everything seems to work fine.

Cheers