Who should read this?
This blog entry is intended for any person who has to develop components to be deployed in PaaS 4 SLA. This entry provides some basic ideas behind PaaS for SLA relevant for software development purposes and pointers to other documentation and resources that extend it.
PaaS for SLA intro
PaaS for SLA, based on ECloud, is a Platform as a Service, PaaS, designed to manage the life cycle events of services deployed on it.
Those services are meant to be elastic. This means that this PaaS scales up and down them at runtime in order to ensure the Quality of Service (QoS) established in the Service Level Agreement (SLA) (e.g. in terms of performance, availability, security, etc.) in front of varying conditions.
Moreover, PaaS for SLA makes transparent to the service provider -and its code the management of the resources needed to guarantee this QoS.
ECloud service model
The ECloud service model is the specification that a software application has to follow (design, implementation, deployment) in order to run it in ECloud as a service.
The current version of the service model specification -[available in the C2NET portal]- details that:
- a service is a deployed and running instance of a service application
- which is composed by several components
- that interact among themselves through channels
Information about channel types (and when to use them), how to prepare components, build a service application and prepare a service is available in the ECloud service model specification.
As you will see: a) part of preparing components, b) defining a service application c) and deploying it requires to define Manifest files. Those configuration files are used by the PaaS for SLA platform in order to know how to handle them.
Preparing components for PaaS for SLA
As software developer in C2NET project probably you will have to prepare (and may be also implement) components to be part of the C2NET service application (cloud side). Thus, you will have to:
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Prepare your software as a component. This implies several things: to define its component Manifest, implement the Component class (used by the PaaS for handling the component) making use of the declared channels...
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Test your component. Check that it is properly deployed in the cloud and that interacts as expected through channels with the components it has to.
Examples
Several examples have been generated in order to show how to prepare components. Currently available examples are:
- Clock Java example. Shows how to prepare a Java based component.
- EchoTest. Shows an example of a nodejs component.
Supporting tools and guidelines
In order to help and support you several tools and guidelines have been generated.