Distributed Denial of Service (DDoS) attacks targeted to cloud services, show serious attack consequences like heavy downtime, economic losses and both short term and long-term business and reputation losses. We present an overview of these attacks and their variants in consonance to cloud infrastructure and explain the attack dynamics. Cloud resource management using auto-scaling algorithms is used to dig the requirements of DDoS mitigation solutions. These requirements include sustainability or budget constraints, controlled auto-scaling, minimization based optimized control of attack traffic, mitigation throughput time (MTT), service quality and availability. Towards the end, we develop and propose a detailed guideline on possible solutions leading to a novel collaborative solution framework based on multi-level alert flows. We also comment on the future attacks in the DDoS space and give a novel DDoS attack variant "Detection Near Impossible (DeNy) DDoS" as an anticipated vision for future attacks to orchestrate the upcoming solutions from the community.