1. A computer system, comprising: one or more processors; system memory; and one or more computer-readable storage media having stored thereon computer-executable instructions that are executable by the one or more processors to configure the computer system to manage applications using service groups, including computer-executable instructions that are executable to configure the computer system to perform at least the following: receive an indication of one or more application dependencies and a plurality of application characteristics to be implemented on a distributed host computer system, the one or more application dependencies describing at least a required computing environment, and the plurality of application characteristics defining a plurality of desired runtime behaviors; based at least on receiving the indication of the one or more application dependencies and the plurality of application characteristics, identify, at the one or more processors, a plurality of applications, from a set of available applications, that are executable within the required computing environment and that each exhibit at least one of the plurality of desired runtime behaviors, wherein the one or more application dependencies include an application dependency defining that at least a first application of the plurality of applications is dependent on a second application of the plurality of applications such that the second application needs to be running for the first application to run; create, at the one or more processors, a manifest that defines a plurality of service groups for implementing the plurality of application characteristics on the required computing environment and within the distributed host computer system, the plurality of service groups including a first service group that executes a first subset of the plurality of applications on the required computing environment within the distributed host computer system to exhibit a first subset of the plurality of desired runtime behaviors, and a second service group that executes a second different subset of the plurality of applications on the required computing environment within the distributed host computer system to exhibit a second different subset of the plurality of desired runtime behaviors; and send the manifest to the distributed host computer system, for loading the first subset of the plurality of applications on one or more first available nodes of the distributed host computer system as part of the first service group, and for loading the second subset of the plurality of applications on one or more second available nodes of the distributed host computer system as part of the second service group.