Compatibility across services is still an open issue, compromising further advance of inter-cloud service provisioning. Cloud market leaders are yet to widely adopt any standardization efforts, but multi-cloud may be the market force that pushes that adoption, breaking down current vendor lockin. ▶ Multi-cloud environments increase the complexity of service level agreements since providers rely on diverse services from a more complex cloud ecosystem. Existing contracts will need to be analyzed and extended so chains of contractual relationships can be automatically established across multiple and heterogeneous cloud providers. ▶ Multi-cloud environments will need virtual networks to be set up across multiple cloud providers. Network performance is still a roadblock for wider cloud adoption, while cloud federation requires extensions to the concept, techniques and primitives of cloud networking. ▶ The constant changes in security parameters enabled by dynamic multicloud management models is amplifying current security concerns.