Bug 1280389

Description of problem:
[RFE] Provide multiplexer for multiple users to get serial-console to the same guest-VM.

The serial multiplexer allows using several serial ports over a single physical serial link connection. In case that multiple users would like to connect to the guest-VM via serial-console, they should have such capability or at least be notified that someone is already using the connection, hence proceeding will drop the active session.

Version-Release number of selected component (if applicable):

Engine:
rhevm-3.6.0.3-0.1.el6.noarch
ovirt-vmconsole-proxy-1.0.0-1.el6ev.noarch                                         
ovirt-engine-extension-aaa-jdbc-1.0.1-1.el6ev.noarch                 
ovirt-host-deploy-1.4.0-1.el6ev.noarch                                                  
ovirt-host-deploy-java-1.4.0-1.el6ev.noarch                                            
ovirt-vmconsole-1.0.0-1.el6ev.noarch

Host:
ovirt-vmconsole-host-1.0.1-0.0.master.20151105234454.git3e5d52e.el7.noarch
ovirt-release36-snapshot-001-2.noarch
ovirt-vmconsole-1.0.1-0.0.master.20151105234454.git3e5d52e.el7.noarch
ovirt-release36-001-2.noarch


How reproducible:
100%

Steps to Reproduce:
1.Try to establish several serial-console connections to one guest-VM from same IP or from different IPs.
2.
3.

Actual results:
ssh -v -t -i $HOME/.ssh/id_dsa -p 2222 ovirt-vmconsole@engine's_IP connect
If trying to initiate second serial console connection from the same IP, then receiving:
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@    WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED!     @
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!
Someone could be eavesdropping on you right now (man-in-the-middle attack)!
It is also possible that a host key has just been changed.
The fingerprint for the RSA key sent by the remote host is                                                                                        
6c:f4:1b:0e:93:7b:01:94:5b:83:d4:9b:c8:c2:65:8e.
Please contact your system administrator.
Add correct host key in /home/nsednev/.ssh/known_hosts to get rid of this message.
Offending RSA key in /home/nsednev/.ssh/known_hosts:2
RSA host key for [10.35.160.204]:2222 has changed and you have requested strict checking.
Host key verification failed.

If trying from another IP, then session is already busy and nothing actually happens:
Available Serial Consoles:
00 RHEL_7_2_VM2[3c0bb6b7-43e1-427c-9575-f58b50a72dae]
01 RHEL_7_2_VM2[3c0bb6b7-43e1-427c-9575-f58b50a72dae]
02 RHEL7_2_VM_1[ea857677-f6d2-4d16-a40a-a44222670482]
03 RHEL7_2_VM_1[ea857677-f6d2-4d16-a40a-a44222670482]
SELECT> 02



Expected results:
Each new connection should get it's own serial-console session or at least to have the ability to kick-off the active session, or to be notified that session is already occupied.

Additional info:
Problematic scenario from https://bugzilla.redhat.com/show_bug.cgi?id=1278466 was taken in consideration, while openening this RFE.