生成jvm大小，如果小于1G，默认1G.

NewStatefulSet returns a StatefulSet object configured for a name.

PodAffinity returns podAffinity options for the pod.

EnvPodName and EnvPodIP are injected as env var into the ZK pod at runtime, to be referenced in ZK configuration file.

prepareFilesystemContainerName is the name of the container that prepares the filesystem.

PodDownwardEnvVars inject the runtime Pod Name and IP as environment variables.