One of the most frequent topics that comes up when I am discussing ACI with customers, is, “How can we better operationalize ACI?”. In other words, how can we take what we have with ACI, and make it simpler to consume for not only ourselves, but for our Ops staff?
Operationalizing and maintaining contracts between EPGs inside of ACI can be a daunting task, especially if we move beyond Network-Centric deployments and into true Application Modeling with our ACI logical policy configurations. And while we have made vast improvements in the UI in regards to visualizing ACI Contracts between EPGs after APIC Code 3.0, the larger number of Contracts and EPGs for an app, the harder it is to effectively visualize the app and the contract/EPG relationships inside of the application.
The Contract Viewer Application, located in the Cisco ACI App Center. was built to simplify and enhance the ability to view relationships between EPGs and Contracts in your Tenant. Contract Viewer is available for installation on your APIC beginning with the APIC 2.2(1k) Code.
What benefits do I get from Contract Viewer?
Let’s take the EPIC EMR application as an example. For this application, we have built out the application EPGs in App-Centric mode, and have contracts defined, which are consumed and provided appropriately.
Note – Since 3.0, the GUI has given you the ability to simplify and isolate EPG to Contracts by selecting the “on click” button natively, but in my experience, the Contract Viewer App is still superior in the simplification process.
The following screenshot is from the APIC GUI itself. While this is a nice high-level overview of our EPIC application, it becomes difficult to understand which contract is being consumed and provided from which EPG, especially as the number of EPGs and Contracts increase.
The Contract Viewer App
Once the Contract viewer application has been installed, you won’t access the App from the “Apps” Tab in the APIC; you will access the Contract Viewer app from instead of your respective Tenants (Tenant > Tenant EPIC3 > Contract Viewer.
Below is a view of the same EPGs and Contracts for the EPIC application using the Contract Viewer Application.
- On the left side we have the Source EPG; this represents the EPG whereby the Contract is consumed
- The Contracts for Application sit in the middle
- On the right we have the Destination EPGs; this represents the EPG whereby the Contract is being provided
Contract Viewer gives you the ability to highlight a single source EPG, Contract, or Destination to reduce the clutter even further as shown below. I have highlighted just the ClientAccess EPG in order to determine exactly which contracts it is consuming, and which EPGs are providing those contracts.