Distributed Tensorflow Cannot Use tf.variable

Symptom

The following error occurs when tf.variable is used across multiple machines and multiple GPUs: WARNING:tensorflow:Gradient is None for variable:v0/tower_0/UNET_v7/sub_pixel/Variable:0.Make sure this variable is used in loss computation

**Figure 1** Distributed Tensorflow unavailable

Figure 1 Distributed Tensorflow unavailable

Possible Cause

Distributed TensorFlow needs to use tf.get_variable instead of tf.variable.

Solution

Replace tf.variable in the boot file with tf.get_variable.