Ubuntu 26.04 LTS – cloud-init hangs and instance provisioning never completes – Fix & Prevention

📖 ~1 min read

Table of contents

1. Symptom & Impact
2. Environment & Reproduction
3. Root Cause Analysis
4. Quick Triage
5. Step-by-Step Diagnosis
6. Solution – Primary Fix
7. Solution – Alternative Approaches
8. Verification & Acceptance Criteria
9. Rollback Plan
10. Prevention & Hardening
11. Related Errors & Cross-Refs
12. References & Further Reading

Symptom & Impact

Instance remains in initializing state and automation dependent on cloud-init never runs.

Environment & Reproduction

Seen with datasource detection issues, malformed user-data, or unreachable metadata endpoints.

cloud-init status --long
systemctl status cloud-init cloud-config --no-pager
cat /etc/cloud/cloud.cfg
journalctl -u cloud-init -n 120 --no-pager

Root Cause Analysis

cloud-init cannot complete datasource fetch or module execution sequence due to input or networking faults.

Quick Triage

Check datasource detection and module stage where execution stops.

cloud-init query ds
cloud-init analyze show
cloud-init analyze blame

Step-by-Step Diagnosis

Validate user-data and replay cloud-init logs to locate parsing or timeout errors.

sudo cloud-init schema --system
sudo cat /var/log/cloud-init.log | tail -n 200
curl -s http://169.254.169.254/latest/meta-data/ || true

Solution – Primary Fix

Correct cloud-config syntax, clean state, and rerun initialization safely.

sudo cloud-init clean --logs
sudo cloud-init init
sudo cloud-init modules --mode=config
sudo cloud-init modules --mode=final

Solution – Alternative Approaches

Pin datasource list explicitly when auto-detection is unreliable.

printf 'datasource_list: [ Ec2, None ]
' | sudo tee /etc/cloud/cloud.cfg.d/90-dslist.cfg
sudo cloud-init clean --logs
sudo reboot

Verification & Acceptance Criteria

Accepted when cloud-init reports done and expected provisioning artifacts exist.

cloud-init status --wait
cloud-init status --long
systemctl is-active cloud-final

Rollback Plan

Restore previous cloud-init config snippets if explicit datasource settings regress behavior.

sudo rm -f /etc/cloud/cloud.cfg.d/90-dslist.cfg
sudo cloud-init clean --logs
sudo reboot

Prevention & Hardening

Validate user-data in CI and test cloud image behavior per provider template.

cloud-init devel schema --config-file user-data.yaml
cloud-init analyze show

Related Errors & Cross-Refs

Related errors include datasource timeout, invalid cloud-config, and cloud-final service failed.

Related tutorial: View the step-by-step tutorial for Ubuntu 26.04 LTS.

View all Ubuntu 26.04 LTS tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

cloud-init docs, Ubuntu cloud image guidance, and provider metadata service references.