Look beyond

Comments

Post a Comment

Popular posts from this blog

How to include CSS, JS and Image in Liferay Portlet JSP

Image
In Init.jsp,  add the following plug-ins to enable CSS and JS to be loaded inside a portlet. <%-- CSS, JS --%> <link href="/o/contact-us-portlet/css/portlet-main.css" rel="stylesheet" /> <script src="/o/contact-us-portlet/js/portlet-main.js"></script> The path starting with /o/(portlet-name)/  is automatically appended to main url (ex. localhost:8080/o/..) /o/(portlet-name)/  represents resources/META-INF/resources One thing to keep in mind is that the above initialization should be done after <liferay-theme:defineObjects /> <portlet:defineObjects /> I DO NOT KNOW WHY ... In view.jsp. can get path through request src="<%=request.getContextPath()%>/images/form-icon.png" Prerequisite: In bnd.bnd Web-ContextPath: /contact-us-portlet  should be set . ------------------------------------------------------------------------- Today's trouble sh...
Read more

AWS Web App 3-tier Architecture

Image
1. A user will query Route 53 for an alias record. 2. Using the alias record, the user will go straight to Elastic Load Balancer which is in the public subnet as it has to be accessible from the World Wide Web(WWW). 3. Behind the ELB, There is the Auto Scaling Group. In order for the ASG to be highly available, it is split between two Availability Zones. The ASG spins up EC2 instances (4 instances and two in each AZ in the diagram). 4. The ELB spreads out the load onto each instance. Instances can be added as scale-out or removed as scale-in which allows the ASG to be responding to high traffic or low traffic. 5. The instances usually talk directly to RDS (Relational Database Service) database to do some operations. For resilience to failure, RDS master has RDS slave (standby replica) using cross-AZ replication. If the master RDS db fails, the application automatically fall over to RDS slave. 6. ElastiCache cluster (mainly Redis) allow the application to read stuff o...
Read more