Tensorflow: Unable to Save checkpoint after every 2 global steps during training the SSD model object detection
Use the saver class:

saver = tf.train.Saver()
with tf.Session() as sess:
    # Run your ops here with sess.run()
    saver.save(sess, 'my-model', global_step=2)


This will create checkpoint files with prefix my-model at every 2 time steps.

Reference: https://www.tensorflow.org/guide/saved_model