Containerization in Cloud Computing: performance analysis of virtualization architectures

La crescente adozione del cloud è fortemente influenzata dall’emergere di tecnologie che mirano a migliorare i processi di sviluppo e deployment di applicazioni di livello enterprise. L’obiettivo di questa tesi è analizzare una di queste soluzioni, chiamata “containerization” e di valutare nel dettaglio come questa tecnologia possa essere adottata in infrastrutture cloud in alternativa a soluzioni complementari come le macchine virtuali. Fino ad oggi, il modello tradizionale “virtual machine” è stata la soluzione predominante nel mercato. L’importante differenza architetturale che i container offrono ha portato questa tecnologia ad una rapida adozione poichè migliora di molto la gestione delle risorse, la loro condivisione e garantisce significativi miglioramenti in termini di provisioning delle singole istanze. Nella tesi, verrà esaminata la “containerization” sia dal punto di vista infrastrutturale che applicativo. Per quanto riguarda il primo aspetto, verranno analizzate le performances confrontando LXD, Docker e KVM, come hypervisor dell’infrastruttura cloud OpenStack, mentre il secondo punto concerne lo sviluppo di applicazioni di livello enterprise che devono essere installate su un insieme di server distribuiti. In tal caso, abbiamo bisogno di servizi di alto livello, come l’orchestrazione. Pertanto, verranno confrontate le performances delle seguenti soluzioni: Kubernetes, Docker Swarm, Apache Mesos e Cattle

Kubernetes as an Availability Manager for Microservice Based Applications

The architectural style of microservices has been gaining popularity in recent years. In this architectural style, small and loosely coupled modules are deployed and scaled inde-pendently to compose cloud-native applications. Microservices are maintained and tested easily and are faster at startup time. However, to fully leverage from the benefits of the archi-tectural style of microservices, it is necessary to use technologies such as containerization. Therefore, in practice, microservices are containerized in order to remain isolated and light-weight and are orchestrated by orchestration platforms such as Kubernetes. Kubernetes is an open-source platform that defines a set of building blocks which collectively provide mecha-nisms for orchestrating containerized microservices. The move towards the architectural style of microservices is well underway and carrier-grade service providers are migrating their lega-cy applications to a microservice based architecture running on Kubernetes. However, service availability remains a concern. Service availability is measured as the percentage of time the service is provisioned. High Availability (HA) is a non-functional requirement for service availability of at least 99.999%. Although the characteristics of microservice based architec-tures naturally contribute to improving the availability, Kubernetes as an orchestration plat-form for microservices needs to be evaluated in terms of availability. Therefore, in this thesis, we identify possible architectures for deploying stateless and stateful microservice based ap-plications with Kubernetes and evaluate Kubernetes from the perspective of availability it provides for its managed applications. Our experiment’s results show that the healing capabili-ties of Kubernetes are not sufficient for providing high availability, especially for stateful ap-plications. Therefore, we propose a State Controller which integrates with Kubernetes and allows for state replication and automatic service redirection to the healthy microservice instance. We conduct experiments to evaluate our solution and compare the different archi-tectures from an availability perspective and scaling overhead. The results of our investiga-tions show that our solution improves the recovery time of stateful microservice based appli-cations by 55% and even up to 99% in certain cases

NoSQL Databases in Kubernetes

With the increasing popularity of deploying applications in containers, Kubernetes (K8s) has become one of the most accepted container orchestration systems. Kubernetes helps maintain containers smoothly and simplifies DevOps with powerful automations. It was originally developed as a tool to manage stateless microservices that run seamlessly in containers. The ephemeral nature of pods, the smallest deployable unit, in Kubernetes was well-aligned with stateless applications since destroying and recreating pods didn’t impact applications. There was a need to provision solutions around stateful workloads like databases so as to take advantage of K8s. This project explores this need, the challenges associated and the available solutions for running databases in Kubernetes. Most of the current research is focused towards SQL-like databases in K8s even though the DNA of NoSQL distributed databases is more aligned with K8s. With no research being done with NoSQL databases, this project outlines the process behind setting up two famous NoSQL databases in K8s: MongoDB and Cassandra. The project also shows a representative viewpoint of the performance comparison between them using the YCSB benchmark. The project lays a foundation around the setup of these databases using K8s Operators and their benchmarking. The goal of the project is to describe the advantages of having databases in K8s, provide developers a clear path for setup and provide insights on basic benchmark performance