Tomcat 6: Evolving our server

Tomcat 6: Evolving our service Preface Debugging Valves Apache WS + Tomcat Load Balancing Clustering Monitoring

Introducing our project Mobile based online marketing project J2EE technology: scalable and robust. To serve applications we need Tomcat. Ubuntu server under three enviroments: develop, preproduction and production. Servers with external provider. Mobile Web and Proxy in the same app.

Architecture Web Proxy Backend MySQL Tomcat Server Client Server Shared Database Server

Challenge: Testing integration Qustodian Backend needs a fixed URL to connect. We develop the project with IDE and debugger. We can't emulate client conection to our system. Conclusion: Dificult to locally debug.

Solution: Remote debugging Tomcat has a connector that allows to debugger to plug in to the server. Using Java Platform Debugger Architecture (JDPA)and Java Debug Wire Protocol (JDWP) Configuring Tomcat in catalina.sh to start in debug mode adding to CATALINA_OPTS variable with export. Another script to invoke Tomcat with this options to avoid editing everytime. -Xdebug -Xrunjdwp:transport=dt_socket,server=y,address=8000

Remote debugging In NetBeans you can start remote debugger in these buttons: And configure it with:

Challenge: Following server request Service starts being bigger. Mobile applications connects to Proxy REST API. Backend request to Proxy. Is a good practice to follow users activity. In Apache Web Server we have an access log. Easy to detect bad requests or attacks.

Previous concept: Valves Valves are Tomcat components which is inserted into request processing pipeline for the associated Catalina container. Several applications in Tomcat: Access Log Remote Address or Host Filter Authentication More ...

Solution: AccessLogValve We only need to uncomment in server.xml the line: <Valve className="org.apache.catalina.valves.AccessLogValve" directory="logs" prefix="localhost_access_log." suffix=".txt" pattern="common" resolveHosts="false"/> The common pattern show log entries in this way: REMOTE_HOST - REMOTE_USER DATETIME "REQUEST_FIRST_LINE" HTTP_STATUS_CODE BYTES_SENT There are others log patterns and options to configure, as conditional logging can be found here .

Access Log applications There are many software handling the access log to show it in graphical mode improving its analysis. Some examples are: http://www.weblogexpert.com/ http://www.hping.org/visitors/

Challenge: Hide pass in request Mobile clients make the request to login. Avoid storing passwords in the log file. Hide password string from request under * characters. http://m.server.com/api/users/login?pass= **** &device_platform=200

Challenge: Better performance In our service, user activity started growing soon. We had a main critical operation: publishing campaigns to users. Campaigns to 4000 users approx. Too many connections: threads in heap memory and DB connections

Solution: Improve server We asked for RAM memory Updated OpenJDK to last Oracle JVM. Updated the Apache Tomcat version Modified Tomcat start with new memory params

Challenge: High Availability Shorten deployment time in production. Minimize impact of server down to users.

Solution: Load Balancing High Availability performance and scalability. Ask for two or more nodes with Tomcat. Apache Web Server as balancer component. Mantain session persistence across the nodes

Apache and Tomcat Apache Web Server redirecting traffic to nodes. Apache schedule the request with algorithms. Sticky sessions as solution to avoid session lost. Using mod_jk or mod_proxy connectors.

Apache as balancer with mod_proxy Copy the modules to mods-enabled directory proxy_ajp.load -> ../mods-available/proxy_ajp.load proxy.load -> ../mods-available/proxy.load proxy.conf -> ../mods-available/proxy.conf proxy_balancer.load -> ../mods-available/proxy_balancer.load Configure proxy_balancer.conf <Proxy balancer://mycluster> BalancerMember http://192.168.1.50:8080 BalancerMember http://192.168.1.51:8080 </Proxy> ProxyPass /test balancer://mycluster

BrightBox has a balancer BrightBox provides a Load Balancer highly configurable with limitations: Depends on IP:PORT Least Connection : scheduler which means connections are allocated to the server with the least number of connections 5 min Sticky Session Server can not access to balancer IP We have a fast solution and more problems ...

Architecture Web Proxy Backend MySQL Tomcat Server Client Server Database Server Web Proxy Tomcat Server Web Proxy Tomcat Server B 2 1 Balancer

Challenge:Keeping session Mobiles usually changes IP each request, so we lose session. If server goes down, you need to login again in other.

Solution: Session Replication Session replication in Tomcat cluster. Two algorithm: SimpleTcpReplicationManager DeltaManager Communication over: IP Multicast IP Sockets Session-state persistence: In memory (SimpleTcpCluster) Database persistence (JDBCManager) File-based persistence (PersistenceManager)

IP Sockets in-memory replication Application must be “ distributable ” in web.xml Stored objects in session must be serializable . All session attributes are replicated for each HTTP Request Valves to filter the replication.

Architecture Web Proxy Backend MySQL Tomcat Server Client Server Database Server Web Proxy Tomcat Server Web Proxy Tomcat Server B 2 1 Balancer Session Replication

Challenge: Monitoring Tomcat Server activity Show request time Watch server load Alerts if server goes down

Solution:Three services Monit – installed in server, to trigger actions under conditions NewRelic – installed in tomcat, to monitoring application and server memory, request … Pingdom – installed in iPhone, service that alerts you if server goes down.

Tomcat 6: Evolving our server

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Tomcat 6: Evolving our server