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Showing posts from February, 2017

Time Warp: Business Cycle Testing

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"Let's do the time warp again..." Video A video version of this blog Business Cycle with Time dependencies? What is a business cycle and why do I need to test it?  I'm really talking about any type of business process that has time based business rules.  The rules can periodic in that they fire on a regular basis or they can one-time based on some time based criteria.  Most of the ones I've worked with are contract oriented or billing cycle oriented. Examples include telecom contracts, home mortgage servicing systems, term based insurance to just name a few.   They usually have some time based sequence of operations, date based rules and may have some type of state machine.   Testing is complicated by the fact that data may need to be of a certain age before processing begins.  Loan payments may need to be delinquent.  An insurance policy may start the renewal process some time before expiration.  Collateralize debt may have payment, reimbursement  an

AWS Relationships between EC2, ELB and ASG

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This post describes the basic relationships of ELBs (now ALBs), EC2 instances and ASGs.  I used AWS for over a year before I realized how Auto Scaling Groups actually interacted with ELBs and EC2 instances. Terms EC2: An Amazon virtual machine used to host applications and services.  EC2 instances can be pooled for scale or failover.  EC2 instances can be based on any of the Amazon EC2 machine types. Elastic Load Balancer (ELB): The basic load balancer provided by Amazon.  They are used as a reverse proxy servers for pools of EC2 instances.   ELBs determine instance health via basic health check operations. Auto Scaling Group (ASG): A control mechanism that manages how many EC2 instances make up a pool. ASGs will create new EC2 instances based on configured pool sizes. They can also auto-scale up and auto-scale down the pool sizes based on load.  ASGs can register created EC2 instances with associated ELBs. Availability Zones (AZ): An Amazon region is made up of variou