Rebooting an application

[Kevin Shallenberger]

Hello all,
I have a client/server program where I'd like to be able to "reboot" the
server without losing the client connections and some of the objects.
Essentially I'd like to be able to update the server code without bringing
it down. It takes ~5 min to startup so it'd be nice if I could maintain the
larger objects. How would I be able to work this out?

Thanks,
Kevin

 

[VK]

Serialization

 

[Kevin Shallenberger]

That takes care of transferring the objects. Now how do I move the client's
socket connection over to the newly started app without disconnecting?

 

[ak]

Hello all,
I have a client/server program where I'd like to be able to "reboot" the
server without losing the client connections and some of the objects.
Essentially I'd like to be able to update the server code without bringing
it down.

Write your own ClassLoader, and update the server code without rebooting

 

[Chris Uppal]

That takes care of transferring the objects. Now how do I move the
client's socket connection over to the newly started app without
disconnecting?

Probably your best bet is to re-engineer the communication protocol so that
clients understand that the server will sometimes disconnect, and will
reconnect automatically when they need to.

-- chris

 

[Andy Fish]

the key to this is making the design as stateless as possible. Have all the
paraphernalia asssociated with a particular connection separated out and
made serializable

you can't reconnect an actual tcp/ip socket, so you will need to make your
communication protocol connectionless (or semi-connectionless) and pass
something akin to an HTTP cookie backwards and forwards when reconnecting

if you don't want the client to disconnect after every request, I would
prefer having the client volunteer to disconnect after a certain amount of
idle time rather than force the server to shutdown with the TCP connections
still active. That way when you want to shut the server down you don't need
to worry about one of the clients being in the middle of a transaction - you
can disallow new connections and wait for all the existing clients to
timeout.

Andy