Hi Tang,
Tang Yong wrote:
> Hello KM,
> Hello GF)Dev Teams,
>
> I have a problem related "rendezvousWithDAS" of NodeAgent.
>
> According to the content of "rendezvousWithDAS" method in CreateNodeAgentCommand.java,
> I found that If the created NodeAgent is at the same machine as the DAS, the NodeAgenet will not
> rendezvous with the local DAS until the nodeagent has been starting up.However, if the NodeAgent
> is at the remote machine and will be controlled by the central DAS, the remote NodeAgent will rendezvous
> with the central DAS when the remote NodeAgent is created.
>
I think you are referring to the code that has a specialized path for
installer (localRendezvous for installer-created DAS and NA. Installer
team would know better why they chose create a parallel for available
api. The javadoc above the method does acknowledge the risk of this
specific path.)
Other than that there is no segregation of response to local/remote DAS.
> So, I am eager to want to know that why the remote NodeAgent needs to rendezvous with the central DAS
> when the remote NodeAgent is created? Why did not the process of "rendezvous with the central DAS" put in
> the remote NodeAgent startup?
>
> In addition,I have some considerations about the problem:
> 1 If when the remote NodeAgent is created, the remote NodeAgent will not rendezvous with the central DAS,
> then,the remote NodeAgent can still finish the action of rendezvous during the nodeagent's startup.After all,the
> central DAS's MBeanServer's ConnectionInfo can be aquried during the nodeagent's startup.
>
> 2 Whether or not the design is based on the performance of nodeagent startup?
>
> 3 What differences (or advantage) are the two modes(rendezvous with the central DAS in "creating phase " vs "starting phase")?
>
Rendezvous is the process of handshake. Earlier the handshake, earlier
the binding between nodeagent and DAS.
So an attempt is made during nodeagent creation to check if DAS is
running at the co-ords specified during create-node-agent and if so a
handshake is attempted.
It is ok if nodeagent cannot rendezvous at this point.
Starting phase rendezvous is a must. Before starting (for the first
time) NA has to know which DAS to sync from (it does not have its config
without that)
So this rendezvous is mandatory (if it has not happened before).
Rendezvous does not happen twice. Sync happens n times.
I wouldn't hint at performance improvement by pushing rendezvous during
create (it's not a heavy operation unlike sync). It's an attempt to know
bindings at the earliest chance (especially when there is no t much
performance hit in doing so)
Nandini
> Could you please to help me solve the above problems?
>
> thanks very much!
>
> Best Regard!
>
> ----------Mike.Tang
>