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All the sites and VPN Infras needs a set of inputs respectively. In Casablanca release, SDC is not capable to support multiple sets of inputs in one service template so that we have to design the sites and VPN infra as a service and use 3 service templates to describe each kinds of node. The CCVPN service is created by mean of separate multiple Service Orders , with one service orderItem for each of the services that makes up the CCVPN connectivity Service.
Such solution, on the one hand, obviously, violates the idea of using one service template to create a CCVPN service. A CCVPN service consists of several site service and VPN service which in fact should be resource; On the other hand, Customers couldn't choose which site or VPN Infra to be included when instantiating a real service because all these resources are regarded as a service.
But if the service template could support multiple instances inputs, we can design all the Site, SOTN and SD-WAN as resources into one service, which would be more reasonable.
Requirements
- Modeling team accepts multiple node design in service template template instances in service template (which means to provide the List type of inputs so that multiple sets of inputs can be supported in one service template
Note:
1）TOSCA service templates specify a set of nodes that need to be created at service deployment time. Some service templates may include multiple nodes that perform the same role. For example, a template that models an SD-WAN service might contain multiple VPN Site nodes, one for each location that accesses the SD-WAN. Rather than having to create a separate service template for each possible number of VPN sites, it would be preferable to have a single service template that allows the number of VPN sites to be specified at deployment time.
2) According to our discussion with Tosca team, the List type of inputs is also one of the needs of TOSCA 1.2.
(Anatoly Katzman Hui Deng Andy Mayer Former user (Deleted) ) - SDC supports multiple node design of List inputs in TOSCA service template (Ofir Sonsino )
1) On Design interface List type of resources can be provided
2) Tosca parser supports parsing of List type of inputs
3) Database supports store List type of inputs - SO support List input interface(Seshu Kumar Mudiganti )
The ideal solution should be that a CCVPN service can be instantiated by using one service template and customers can decide the number of resources when creating a service.
TOSCA working group also pays attention to this problem and they came up with an improved service templates which can satisfy our needs:
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Keyname
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Required
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Type
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Constraints
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Description
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occurrences
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no
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range of integer
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when not specified, defaults to [1,1]
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The optional minimum and maximum number of instances that can be created from this node template. If not specified, only one single instance can be created.
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instance_count
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no
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integer
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when not specified, defaults to the lower bound of the range specified by the ‘occurrences’ keyname
The requested number of runtime instance of the node template.
To satisfy this needs, an optimization on service template– List type of inputs should be supported
see Reference:
1, TOSCA Enhancements to Support Multiple Node Template Instances
2, SOTN VPN Infra Service CSAR File in C release
3. CCVPN ONS Demo in 2018 ONS-RU