CI/CD: Continuous Integration, Continuous Delivery

Telecom operational environments are multifaceted and unique to each operator. Each CSP has a different mix of legacy systems, proprietary software, and multi-vendor hardware platforms and interfaces. Widely used in more uniform, less complex IT and webscale networks, DevOps needs to be adapted to deliver software in telco multiple domain environments where third-party software and hybrid cloud environments are typical.
Realizing the benefits of DevOps-style, iterative software development in the telecommunications environment calls for a different many-to-many delivery and operations process that Nokia refers to as DelOps (delivery and operations). Like DevOps, DelOps uses agile processes to reduce time to market for new products and features, but it uses a different integration process for each environment or platform, with design, deploy, test and operate phases.

One of the drivers for adopting software-driven networks with cloud-native cores is enabling CSPs to roll out services faster, while minimizing operational risk. Improving reliability and efficiency, while managing the complexity of frequent micro-services changes in a telecom network, would be a close to impossible task without automating the software lifecycle, which we refer to as CI/CD.

CI/CD requires an evolution in thinking. The uniqueness and complexity of CSP networks call for closer cooperation between vendor and operator than ever before. Flexibility and openness are required on both sides to adjust strategy, processes and organizations to allow CI/CD to realize its promised benefits.

It encompasses the software development steps of plan, develop (or code), build and test phases of software development, which taken together represent the CI (continuous integration) phase.

Software delivery, network and service planning and design, and the deploy, integrate and test stages constitute the CD (continuous delivery) phase. The CI and CD stages are interlinked and closely follow each other as they move into the operations stage. Regardless of vendor, key common tools in a CI/CD pipeline include a software repository, a lifecycle management and orchestration tool, and a test manager.

One of the most critical yet time-consuming phases of software development and deployment is testing. Following product testing, which is executed at the software development stage, validation and acceptance testing is performed prior to software deployment to the customer’s live network. This is the stage when the software is finally tested in the CSP’s pre-production environment.

Traditionally, testing was performed manually needing a longer period of time to execute often risking human errors. Automating testing is key to delivering the time-to-market and reliability benefits of CI/CD. At Nokia, we distinguish four distinct validation test cases: lifecycle management validation, functional regression testing, capacity benchmarking and robustness testing. These test cases can be executed sequentially in an automated manner mostly using real user equipment to ensure service quality.