AppendEnv appends envs `b` into `a` ignoring envs whose names already exist in `b`.

GetPodOrdinals gets desired ordials of member in given TikvCluster.

IsOwnedByTikvCluster checks if the given object is owned by TikvCluster.

IsSubMapOf returns whether the first map is a sub map of the second map.

RetainManagedFields retains the fields in the old object that are managed by kube-controller-manager, such as node ports.

SortEnvByName implements sort.Interface to sort env list by name.