How A/B Testing Supports VNF CI/CD

3/5/2019

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As a consumer of information and communications technology and services, software updates are an occasional annoyance, at worst requiring a device restart. For a network or IT administrator software updates are a more onerous undertaking and often have to be carried out at night when user activity is low. As network infrastructure becomes increasingly virtualized the cadence of software updates will accelerate, with vendors striving to make security patches and new features available to their customers in a stream of continuous releases. The network operator will then face the challenge of how to continuously deliver these updates to the production network.

We explore this topic in the latest Heavy Reading white paper: "Simplifying Continuous Deployment with A/B Test: A Phased Approach to VNF Upgrades." As operators start to launch 5G networks they are also preparing for the migration to cloud-native technology. In order to keep up with ever-increasing customer expectations, operators are looking to adopt agile software development to shorten time to market. To improve software quality and increase cost efficiency they are also embracing DevOps, breaking down the barriers between software engineering and operations. The incremental updates associated with DevOps require a concomitant adoption of Continuous Integration and Continuous Delivery/Deployment (CI/CD) so that any quality issues can be quickly identified and fixed.

As the ETSI draft report on CI/CD and DevOps for NFV (ETSI GS NFV-TST006) notes: "Smaller, incremental releases of VNFs and VNFCs can be rapidly promoted through a continuous integration/delivery pipeline …. The use of discrete functions and APIs help to promote rapid evolution and delivery of services in a complex, multi-vendor environment. To recognize the full benefits of DevOps, significant process retooling may be required."

The Heavy Reading white paper explores various approaches to Continuous Delivery/Deployment in the telecom domain, in particular A/B Testing which enables hitless upgrades with fewer resources (e.g. virtual machines) than other methods. As software upgrades move from two or fewer per year to ten or more, there needs to be a significant simplification in the planning and preparation process so that this can be reduced from months to a matter of days. Because software upgrades will be much more frequent (and potentially contemporaneous), operators will want to minimize the amount of resources (VMs and staff) during the upgrade process.

The phased approach of A/B Test holds several benefits over the current industry norm for VNF upgrading. Service downtime can be eliminated. Upgrades can be done gradually during the day when more of the operations team is available to deal with any unexpected problems. Fewer redundant resources (VMs) are required during the upgrade window. The upgrade process itself is highly automated reducing the amount of staff needed to manage it.

Another advantage of A/B Testing, according to the ETSI draft report on CI/CD and DevOps for NFV, is the continuous feedback it provides: "Real production data is used to guide development and operations practices and priorities. Feature flags can be used to present alternate versions of a feature to different users, providing a way to compare their usefulness and value (A/B testing). This moves software development from the guessing associated with traditional requirements to the real world feedback of how the system is used." To find out more, download the Heavy Reading white paper here.

This blog is sponsored by Huawei.

— James Crawshaw, Senior Analyst, Intelligent Networks and Automation, Heavy Reading