How to create relations between application services based on Dynamic CI Groups

[Amar_Be]

Hi,

I need to create a dependency relation between 2 application services.  But from the Application Services creation wizard, it is not possible to select application services based on Dynamic CI Groups as parent of the current service.

The only solution I've found is to create manually the relations in the cmdb_rel_ci and svc_ci_assoc forms.

Is there a cleaner way of doing it? And does someone have an explanation about this limitation?

I'm in the use case where I've  to represent the dependency of the "windows servers" technical service on the "network" technical service. I think it's not a so uncommon case.

[Barry Kant]

hi Amer_Be

I fail to understand to be honest. 
The discussion starts with Application Services and in the 2nd part you give an example about:
Windows servers technical services and network technical service. 
I assume the technical service (offerings) have a dynamic CI group related containing a number of CIs.
Not sure what the dependency between dynamic CI groups will look like. Would you like to create a depending relation between dynamic CI group with another dynamic CI group?

If you want to understand dependencies between services or offerings then you can use a Service Portfolio view or SPM advanced view inservices or offerings were you can see Service I depends on / Service depending on me related lists. This is also available in Service Builder. 

BR,
Barry

[Amar_Be]

Hi Barry,

It is indeed dynamic ci groups (which are a type of application services )  related to technical service offerings.

I want a dependency between 2 application services where one of them, at least, is based on a dynamic ci group. The idea is to be able to represent the fact that if the network is down, then it is no more possible to access and administer the servers.

On paper, using a CSDM schema, it is a relation depends on/used by between the dynamic ci groups (application services)  "Windows servers"  and "Network". But it is not possible to easily create this relation in ServiceNow.

[SteveMacWWT]

@Amar_Be While Application Services can be comprised of Dynamic CI Groups, not all Dynamic CI Groups are Application Services. What you are referring to aligns to a Technical Service Offering, 

Taken from that perspective, in the Service Builder application you can designate dependencies between Service Offerings. 

I will add a warning for what I believe you are trying to do. A CI should only ever be part of one Dynamic CI Group, otherwise there will be conflicts when the TSO's attributes are cascaded to the CIs.

For example if you have a Server in a Dynamic CI Group (defined by, for example, all CIs of class Server (including it's subclasses)) with the Support Group set to "Global Server Admins", all CIs matching the definition of that Dynamic CI group will get the Support Group automatically assigned as soon as it is added to the CMDB. 

You also have a separate Dynamic CI group set up for Windows Servers in China (class is Windows Server, Location is China) because all servers in China are locked down for regulatory reasons. This set of servers gets their Support Group automatically set to "China Server Admins". 

Now there is a conflict between the two Dynamic CI Groups, and you will have issues with the automatic setting of Support Group. 

This is a long explanation to say: It is not a best practice and can be dangerous to create a Dynamic CI Group that is overly broad, such as you mentioned in your example of servers depending on network. By going that broadly, you've limited one of the best capabilities of Dynamic CI Groups - automatic setting of attributes.

I also have a question: do all your servers depend on any part of the network? If you have one switch go bad, does that necessarily mean all servers are affected? As I read your example, that is what I see resulting from your desire to set up the dependency between the two Dynamic CI Groups. 

Finally, I may be in the minority with this, but I would not model the type of dependency you are asking about. If you are doing this to try to get all dependencies on the network automatically added to an Incident when the network is down, it is probably better to handle that manually.

[Amar_Be]

Thank you Steve for your detailed answer.

The CMDB is currently still empty.  The discovery project as just started. So the purpose of this model is to provide a first overview of the dependencies between the services.

The specific relations between the CIs (servers and routeur for instances) and impacts propagation are going to be managed in the applications maps.

But I agree that it is not because one router is down that the whole network or servers services are  impacted.

So, if I understood correctly, you are recommending creating a relationship between the service offerings to represent, at a high level, the fact that server management requires having network services available?

But again, how can this be done easily (without having to go the the CI relationship form and then filter on the CIs to get the offerings) ?