  Holographic models for the pure gauge QCD vacuum are explored. The
holographic renormalization of these models is considered as required by a
phenomenological approach that takes the $\beta$-functions of the models as the
only input. This approach is done taking the dilaton as the coordinate
orthogonal to the border. This choice greatly simplifies the analysis and gives
a geometrical interpretation for the fixed points of the renormalization group
flow. Examples are constructed that present asymptotic freedom, confinement of
static quarks, either with vanishing or non-vanishing gluon condensate $G_{2}$.
The latter models require an extension of the dilaton-gravity models already
considered in the literature. This extension is also determined by the only
input, i.e. the $\beta$-function. In addition the restrictions imposed by the
trace anomaly equation are studied. In doing so a holographic derivation of
this equation is presented.
