Re: Single virtual tomcat application which serves multiple contexts
On 20/01/2012 15:56, Egor Samarkhanov wrote: Hello ! I have multiple clients: client 1 - 40 users client 2 - 50 users client 3 - 60 users And I have a web application that is supposed to serve the clients. The application is deployed into Tomcat. Each client has it's own database. What I want to implement is the single web application instance which servers all the clients. The client (and the database to connect to) is identified by the context path from the URL. I.e. I imply the following scenario: 1. Some user requestes the http://mydomain.com/client1/ 2. Tomcat invokes a single instance of my application (no matter which context is requested) 3. My application processes the rest of the request thinking that it's deployed to /client1 context path, i.e. all redirect or relative URLs should be resolved against http://mydomain.com/client1/ When the client 2 requests the http://mydomain.com/client2/, I want my application (the same instance) now process it just like if it was deployed to /client2 context path. Is this possible in Tomcat? No, it's not. If you want to build a multi-tenant application, you should: 1. Make your application the ROOT application. 2. Then use the first part of the path to determine which tenant. 3. Use the path data to select a configuration as required. What is the benefit in making it one application? p -- [key:62590808] signature.asc Description: OpenPGP digital signature
Re: Single virtual tomcat application which serves multiple contexts
Egor Samarkhanov wrote: Hello ! I have multiple clients: client 1 - 40 users client 2 - 50 users client 3 - 60 users And I have a web application that is supposed to serve the clients. The application is deployed into Tomcat. Each client has it's own database. What I want to implement is the single web application instance which servers all the clients. The client (and the database to connect to) is identified by the context path from the URL. I.e. I imply the following scenario: 1. Some user requestes the http://mydomain.com/client1/ 2. Tomcat invokes a single instance of my application (no matter which context is requested) 3. My application processes the rest of the request thinking that it's deployed to /client1 context path, i.e. all redirect or relative URLs should be resolved against http://mydomain.com/client1/ When the client 2 requests the http://mydomain.com/client2/, I want my application (the same instance) now process it just like if it was deployed to /client2 context path. Is this possible in Tomcat? Personal opinion: By putting some considerable effort into it, it is certainly possible to do something like that, by rewriting URLs and/or proxying and/or making all your pages refer to the context etc.. But the question is : why ? If - you have many, many clients - or you application is so big that having multiple copies of it totally fills your disk - or your application for client1 needs to share data with the application for client2 then it may be worth thinking about this. But otherwise, you probably would immensely simplify your life by using a separate virtual host for each client, and have for each virtual host a separate appBase, in which you just deploy a copy of your application. Think of the security issues otherwise, to avoid one client being ever able to access the data of another; or think of what happens when one of these clients in the future asks you for that little change just for him.. etc.. - To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
Re: Single virtual tomcat application which serves multiple contexts
André, Thanks for your notes! Please see my comments inline. AW Personal opinion: AW By putting some considerable effort into it, it is certainly possible to do something like AW that, by rewriting URLs and/or proxying and/or making all your pages refer to the context AW etc.. AW But the question is : why ? AW If AW - you have many, many clients Yes, I do have really many clients, and hope to get even more. And in future I'd like to implement a failover solution with Tomcat cluster. If i have these many applications deployed, then they will be deployed on all nodes. I guess it would be much better if one node contains a single application which can serve any client (plus session replication). This way the cluster would be more effective. AW - or you application is so big that having multiple copies of it totally fills your disk It's pretty big, but the disk space is not the real concern, but the memory. Many deployments of the same application consume lots of PermGen. AW - or your application for client1 needs to share data with the application for client2 No, it doesn't. AW then it may be worth thinking about this. AW But otherwise, you probably would immensely simplify your life by using a separate virtual AW host for each client, and have for each virtual host a separate appBase, in which you just AW deploy a copy of your application. By the way, I was thinking about virtual hosts, but I didn't find any solution yet to add new virtual hosts at runtime (to tomcat, or to apache httpd). AW Think of the security issues otherwise, to avoid one client being ever able to access the AW data of another; Good point. AW or think of what happens when one of these clients in the future asks you AW for that little change just for him.. etc.. Yes, thinking about it all the time. But we didn't have such cases for 2 years, and if it happens - we would deploy the customized version to some other, separate environment. So, where do I start if I decide to go with the single virtual application? Did someone try doing such things? -- Best regards, Egor Samarkhanov (ego...@actimind.com) Actimind, Inc. - To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
Re: Single virtual tomcat application which serves multiple contexts
Egor Samarkhanov wrote: André, Thanks for your notes! Please see my comments inline. AW Personal opinion: AW By putting some considerable effort into it, it is certainly possible to do something like AW that, by rewriting URLs and/or proxying and/or making all your pages refer to the context AW etc.. AW But the question is : why ? AW If AW - you have many, many clients Yes, I do have really many clients, and hope to get even more. And in future I'd like to implement a failover solution with Tomcat cluster. If i have these many applications deployed, then they will be deployed on all nodes. I guess it would be much better if one node contains a single application which can serve any client (plus session replication). This way the cluster would be more effective. AW - or you application is so big that having multiple copies of it totally fills your disk It's pretty big, but the disk space is not the real concern, but the memory. Many deployments of the same application consume lots of PermGen. AW - or your application for client1 needs to share data with the application for client2 No, it doesn't. AW then it may be worth thinking about this. AW But otherwise, you probably would immensely simplify your life by using a separate virtual AW host for each client, and have for each virtual host a separate appBase, in which you just AW deploy a copy of your application. By the way, I was thinking about virtual hosts, but I didn't find any solution yet to add new virtual hosts at runtime (to tomcat, or to apache httpd). AW Think of the security issues otherwise, to avoid one client being ever able to access the AW data of another; Good point. AW or think of what happens when one of these clients in the future asks you AW for that little change just for him.. etc.. Yes, thinking about it all the time. But we didn't have such cases for 2 years, and if it happens - we would deploy the customized version to some other, separate environment. So, where do I start if I decide to go with the single virtual application? Did someone try doing such things? In that case, I would start with an Apache httpd front-end, connected to Tomcat via mod_proxy and mod_proxy_ajp, or via mod_jk. You could then easily proxy any request to your single webapp running under Tomcat. E.g. http://front-end.company.com/client1/webapp - tomcat:/single_webapp http://front-end.company.com/client2/webapp - tomcat:/single_webapp ... http://front-end.company.com/clientn/webapp - tomcat:/single_webapp and use combinations of Proxy rules, Rewrite rules, SetHeaders rules etc.. to make sure that when your webapp returns pages, they correctly continue to refer to client1, client2 etc.. You just have to make sure then that your webapp always has enough information available, to know for which client it is being called. You can also do this with virtual hosts at the Apache level, all proxying to the same back-end tomcat. And there are tricks at the Apache level to handle dynamic virtual hosts. - To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
