The cloud-native vision is becoming the foremost approach in application development, embracing DevOps, containerization, and the deployment of microservices (typically one microservice per container). Microservices have many merits compared to traditional monolithic architecture, with benefits including scalability, portability, flexibility, and resiliency. However, it is important to understand the role of the operating system (OS) in containerization, and we focus here on the Linux OS.
Containers cannot be moved around without consideration to the OS
Containers cannot simply be moved around without consideration to the OS and version the microservice was built on and the container host OS and version. This stems from consideration of the container's user space libraries (the base image) on which the microservice was built. The problem arises when these user space libraries are compiled on different kernel releases from different Linux vendors that implemented different functionality in the kernel.
Ovum discussed the issues faced by independent software vendors (ISVs) as they move to cloud-native technologies with Tal Barenboim and Zeev Likwornik at Amdocs.
Tal Barenboim, technology evangelist, Amdocs Cloud Center of Excellence, said: "Following a thorough investigation with leading industry firms and key stakeholders it became clear to us that a) Linux container user space libraries (base image) have potential incompatibilities running on top of different kernel releases of multiple Linux distributions, b) Linux distribution vendors have no real support model for the above in containers in production use, further preventing container portability and adoption, c) the GPL license was not designed for the container world, and d) some container SDN fabrics are immature for production use of mission-critical applications due to lack of required capabilities and performance impact."
Zeev Likwornik, who leads Amdocs Cloud Center of Excellence, said: "It is clear to us that container portability is overhyped in the current stage of technology maturity. This is one of the key reasons why hardly any ISVs are distributing commercial off-the-shelf software (COTS) over containers. We are collaborating closely with leading communications service providers and vendors to overcome the current portability challenges and clear the way for use of containers."
To read about this issue and how to resolve it, see the Ovum Research Note, "Patterns of container usage: the role of the OS and portability."
Ovum thanks Tal Barenboim and Zeev Likwornik at Amdocs for sharing the challenges faced by ISVs.
"Patterns of container usage: the role of the OS and portability," IT0022-000989 (June 2017)
Michael Azoff, Principal Analyst, Ovum Infrastructure Solutions Group