Google Colab TPU suddenly not found anymore

Question

Issue

Since Monday or Thuesday this week (10.03.2025) the Google Colab TPUs are not found anymore.

Can someone help me please?

I am using

• TensorFlow Version: 2.18.1
• Keras-Tuner Version: 1.4.7

These are my resources

Sie haben Colab Pro abonniert. Weitere Informationen
Verfügbar: 55.47 Recheneinheiten
Nutzungsrate: ca. 3.66 pro Stunde
Sie haben 4 aktive Sitzungen.

This is my code

# TPU Strategy Setup
try:
    print("Connecting to TPU...")
    tpu = tf.distribute.cluster_resolver.TPUClusterResolver()  # Resolving TPU cluster
    tf.config.experimental_connect_to_cluster(tpu)
    tf.tpu.experimental.initialize_tpu_system(tpu)
    print("TPU initialized successfully!")
    strategy = tf.distribute.TPUStrategy(tpu)  # TPU strategy definition
except ValueError:
    print("TPU not found. Falling back to CPU/GPU strategy.")
    strategy = tf.distribute.get_strategy()  # Default CPU/GPU strategy

# Confirm strategy definition
if 'strategy' not in locals():
    raise RuntimeError("TPU strategy setup failed. Please check TPU initialization.")

# Log TPU Configuration
print(f"Using distribution strategy: {strategy.__class__.__name__}")
print(f"Number of replicas: {strategy.num_replicas_in_sync}")

tf.debugging.set_log_device_placement(True)

# Enable Mixed Precision for TPU optimization
policy = mixed_precision.Policy('mixed_bfloat16')
mixed_precision.set_global_policy(policy)
print("Mixed Precision enabled: ", policy)

Output: Connecting to TPU... TPU not found. Falling back to CPU/GPU strategy. Using distribution strategy: _DefaultDistributionStrategy Number of replicas: 1 Mixed Precision enabled: <DTypePolicy "mixed_bfloat16">

I tried dto switch the run time types back- and forward including saving them, restarting the sessions, logging in and out of the Google colab account.

I except to get the TPU found and up and running like last week.

Answer 1

This solution works for me:

!pip install tensorflow==2.18.0
!pip install tensorflow-tpu==2.18.0 --find-links=https://storage.googleapis.com/libtpu-tf-releases/index.html

import tensorflow as tf

try:
    tpu = tf.distribute.cluster_resolver.TPUClusterResolver(tpu='local')
    tf.config.experimental_connect_to_cluster(tpu)
    tf.tpu.experimental.initialize_tpu_system(tpu)
    strategy = tf.distribute.TPUStrategy(tpu)
    print("TPU is running:", tpu.master())
except ValueError as e:
    print("TPU is not avaible:", e)