Smooth redeployment of WAR in production?

Question

I was wondering if there is a \'smooth way\' of redeploying a Java WAR to a production server (no cluster, no OSGi)?

All I can come up with is stop server, update file,

Answer 1

As ZZ Coder has already mentioned load balancer is a good solution especially for big deployments. For my own project I use reverse http proxy functionality of nginx web server. It redirects all http packets from a specified web context (seen from the Internet) to a server inside my network. Configuration is really easy:

location /best-app-ever/ { proxy_pass host-address:8080/some-app-1.1 root /home/www/some-app-1.1 }

Switching version should be smooth as well. Assuming that you have already deployed new version of application just change nginx configuration file and apply changes:

location /best-app-ever/ { proxy_pass host-address:8080/some-app-1.2 root /home/www/some-app-1.2 }

sudo nginx -t
sudo service nginx restart

Be warned that in case your web application is stateful and/or contains some running or scheduled processes, the deployment and undeployment might not be as smooth.