Hetzner Cloud CLI Authentication Bug: Temporary SSH Key Removal

by Mei Lin 64 views

Hey guys! Today, we're diving deep into a tricky bug encountered while deploying PostgreSQL HA clusters on Hetzner Cloud using the Autobase CLI. This issue revolves around authentication failures when trying to remove a temporary SSH key, and we're going to break it down step-by-step. Let's get started!

Bug Description

So, here’s the deal: when you're trying to deploy a PostgreSQL HA cluster on Hetzner Cloud using the Autobase CLI (specifically, the autobase/automation:2.2.0 or :latest docker images), the playbook hits a snag. It throws an “unable to authenticate” error when it tries to remove a temporary SSH key on the Hetzner API. This is super frustrating because the same API token works just fine when you test it with curl against the /servers and /ssh_keys endpoints. Plus, the token has full Read & Write permissions in the project. The weird part? A UI-based deployment works (though it's missing backup/S3 and PgBouncer options), but the CLI consistently errors out at the “Remove temporary SSH key” task.

This bug is a major pain point for those who rely on the Autobase CLI for automated deployments. Imagine setting up a complex PostgreSQL cluster, only to have the process grind to a halt because of an authentication issue. It's like trying to unlock a door with the right key, but the lock just won't budge. This issue highlights the importance of consistent behavior across different deployment methods. While the UI deployment might succeed, the CLI's failure indicates a deeper problem with how the authentication is handled in the automated scripts. This inconsistency not only disrupts workflows but also erodes trust in the automation tool itself. To effectively address this, we need to understand the underlying mechanisms of authentication in the Autobase CLI and how it interacts with the Hetzner Cloud API. By identifying the root cause, we can ensure that future deployments proceed smoothly and reliably, regardless of the deployment method used.

The ability to automate infrastructure deployment is crucial for maintaining efficiency and consistency in modern cloud environments. The fact that the CLI consistently fails at the same task—removing the temporary SSH key—suggests a specific issue with the script's logic or its interaction with the Hetzner Cloud API during this particular step. It could be related to how the API token is being passed, how the request is being formatted, or even a timing issue where the key removal is attempted before the key is fully recognized by the system. The successful UI deployment further complicates the matter, as it implies that the API token itself is valid and has the necessary permissions. This means the problem is more likely confined to the CLI's execution environment or its internal processes. Understanding the specific steps the CLI takes to remove the SSH key, and comparing them with the successful UI deployment, can provide valuable insights into where the discrepancy lies. By addressing this, users can regain confidence in the Autobase CLI and fully leverage its automation capabilities for their PostgreSQL HA clusters.

To further complicate matters, the missing backup/S3 and PgBouncer options in the UI deployment highlight the importance of the CLI for those requiring comprehensive configuration. These features are often critical for production environments, emphasizing the need for a reliable and fully functional CLI. The authentication issue not only blocks the initial deployment but also potentially hinders future management and scaling operations. The temporary SSH key removal, while seemingly a minor task, is a crucial part of the deployment process. If it fails, the entire workflow is disrupted, leaving the system in an incomplete state. This can have cascading effects, making it difficult to troubleshoot and resolve related issues. Therefore, resolving this authentication problem is not just about fixing a bug; it's about ensuring the integrity and reliability of the entire deployment pipeline. By focusing on this core issue, developers and users can build a more robust and trustworthy system for managing PostgreSQL HA clusters on Hetzner Cloud. The long-term benefits include reduced downtime, improved operational efficiency, and a greater ability to leverage the full range of features offered by the Autobase CLI.

Expected Behavior

Ideally, the CLI playbook should successfully authenticate to the Hetzner Cloud API using the project-scoped API token. It should then remove its temporary SSH key and continue provisioning all resources—servers, load balancer, backups, PgBouncer—without any authentication errors. This smooth process is what we're aiming for, ensuring a hassle-free deployment experience.

When the CLI playbook operates as expected, it automates the deployment process seamlessly, reducing the manual effort required and minimizing the potential for human error. This automation is particularly critical in cloud environments where resources are dynamically provisioned and managed. The ability to authenticate to the Hetzner Cloud API and remove the temporary SSH key without issues is a foundational step in this process. The API token serves as the key to accessing and manipulating cloud resources, so any authentication failure can halt the entire deployment. A successful deployment not only creates the necessary infrastructure components but also configures them correctly, ensuring that the PostgreSQL HA cluster is secure, reliable, and ready for production use. This includes setting up load balancing, configuring backups, and integrating essential services like PgBouncer. When the CLI works as intended, it simplifies these complex tasks, allowing administrators to focus on higher-level concerns, such as application optimization and scaling strategies.

Furthermore, the expected behavior includes a consistent and reliable experience across different environments and deployment scenarios. Whether the user is deploying a test cluster or a production-ready setup, the CLI should perform predictably and without authentication hiccups. This reliability is crucial for building confidence in the automation tool and ensuring that it can be used effectively in various contexts. The successful removal of the temporary SSH key is not just a technical step; it also contributes to the security posture of the deployed infrastructure. Temporary SSH keys are often used for initial access and configuration, but they should be removed once the deployment is complete to reduce the risk of unauthorized access. A properly functioning CLI ensures that this security best practice is followed automatically, without requiring manual intervention. This is particularly important in environments where security compliance is a concern. By adhering to these standards, the CLI provides an additional layer of protection, safeguarding the deployed resources and the data they contain. In essence, the expected behavior of the CLI is to act as a dependable and secure automation tool, streamlining the deployment process and ensuring that the infrastructure is set up correctly and securely.

Steps to Reproduce

To recreate this bug, follow these steps:

  1. Generate a project-scoped Hetzner API token with Read & Write permissions and S3 Key too.

  2. Verify the token works:

    curl -H "Authorization: Bearer <HCLOUD_TOKEN>" https://api.hetzner.cloud/v1/servers
curl -H "Authorization: Bearer <HCLOUD_TOKEN>" https://api.hetzner.cloud/v1/ssh_keys

  3. Export the token:

    export HCLOUD_TOKEN=<HCLOUD_TOKEN>

  4. Prepare inventory:

    mkdir -p inventory

  5. Run the CLI deployment (replace placeholders):

    docker run --rm -it \
     -v "$HOME/.ssh:/root/.ssh" \
     -v "$PWD/inventory:/autobase/inventory" \
     -e ANSIBLE_SSH_ARGS="-F none" \
     -e HCLOUD_TOKEN \
     autobase/automation:latest \
     ansible-playbook deploy_pgcluster.yml --extra-vars "\
cloud_provider=hetzner \
hcloud_token=$HCLOUD_TOKEN \
cloud_load_balancer=true \
server_count=3 \
server_type=cx21 \
server_image=ubuntu-22.04 \
server_location=ash \
volume_size=100 \
ssh_public_keys='<SSH_PUB_KEY>' \
postgresql_version=17 \
patroni_cluster_name=meu-cluster \
pgbouncer_install=true \
pgbackrest_install=true \
wal_g_install=false \
hetzner_object_storage_name=dbstorage \
hetzner_object_storage_region=fsn1 \
hetzner_object_storage_access_key=<S3_ACCESS_KEY> \
hetzner_object_storage_secret_key=<S3_SECRET_KEY> \
database_public_access=false"

  6. Observe failure at “Remove temporary SSH key”:

    TASK [… Remove temporary SSH key 'ssh_key_tmp_xxxxx' …]
APIException: unable to authenticate (unauthorized, xxxxx)

By following these steps, you can reliably reproduce the authentication issue. This systematic approach to reproducing the bug is essential for identifying the root cause and developing an effective solution. Each step in the process is designed to isolate the variables and pinpoint the exact moment the failure occurs. The initial steps verify that the API token is valid and has the necessary permissions by querying the Hetzner Cloud API directly using curl. This ensures that the problem is not simply a matter of an invalid or misconfigured token. The export of the token makes it available to the Docker container, which is the environment in which the Autobase CLI operates. The preparation of the inventory directory is a standard step for Ansible playbooks, ensuring that the necessary configuration files are in place. The core of the reproduction process is the execution of the docker run command, which launches the Autobase CLI with the specified parameters. This command includes a complex set of extra variables that define the deployment configuration, such as the cloud provider, server specifications, database version, and backup settings. The final step is to observe the output of the CLI, specifically looking for the “unable to authenticate” error at the “Remove temporary SSH key” task. By consistently reproducing the bug, developers and users can have confidence that the issue is well-understood and that any proposed fixes can be thoroughly tested. This methodical approach is crucial for maintaining the reliability of the automation tool and ensuring that it can be used effectively in different deployment scenarios.

Installation Method

This issue was encountered using the command line.

The installation method plays a crucial role in understanding the context of the bug. By identifying that the issue occurs via the command line, we can narrow down the potential causes and focus on the CLI-specific aspects of the problem. The command-line interface often involves direct interaction with the system's environment and configuration, making it susceptible to issues related to environment variables, file permissions, and command syntax. Unlike a graphical user interface (GUI), which provides a more abstracted and controlled environment, the CLI relies on precise commands and configurations. This means that even a minor discrepancy in the command or the environment setup can lead to unexpected errors. In this case, knowing that the bug occurs in the CLI context allows us to examine the specific commands used, the environment variables set, and the overall execution flow of the script. This detailed analysis is essential for pinpointing the root cause of the authentication failure. It also helps differentiate the problem from potential issues that might arise in other installation methods, such as a GUI-based deployment, where the underlying mechanisms and interaction points are different. By understanding the nuances of the command-line environment, we can better tailor our troubleshooting efforts and develop targeted solutions that address the specific challenges associated with CLI-based deployments.

Furthermore, the command-line environment often provides more granular control and visibility into the deployment process, which can be advantageous for debugging. The ability to inspect logs, trace execution steps, and modify configurations directly makes it easier to identify the source of the problem. For instance, in this case, the command-line approach allows users to execute individual curl commands to test the API token separately, which is a valuable diagnostic step. This level of control is typically not available in GUI-based systems, where the deployment process is often more opaque. The transparency of the CLI environment also enables the use of various debugging tools and techniques, such as setting breakpoints, tracing function calls, and analyzing memory usage. These tools can provide deeper insights into the behavior of the script and help uncover subtle issues that might be hidden in a more abstracted environment. By leveraging the capabilities of the command-line interface, developers and users can effectively troubleshoot and resolve complex problems like the authentication failure described in this bug report. This targeted approach ensures that the solutions are aligned with the specific characteristics of the CLI deployment method, resulting in a more robust and reliable automation tool.

System Info

Here’s the system info:

  • Host OS: Ubuntu 22.04 (or macOS/WSL2)
  • Docker version: 24.x
  • Autobase image: autobase/automation:2.2.0 and latest
  • Hetzner token: project-scoped, Read & Write

Having detailed system information is crucial for diagnosing and resolving the bug. The host operating system, whether it's Ubuntu 22.04, macOS, or WSL2, can influence how the Docker containers interact with the underlying system and the network. Different operating systems have varying configurations and security settings that may affect the behavior of the Autobase CLI. For example, file permission issues or network configuration problems might manifest differently across these platforms. Knowing the Docker version, specifically 24.x, helps ensure compatibility and identify any known issues associated with that version. Docker's behavior and API can change between versions, so understanding the specific version in use is essential for troubleshooting. The Autobase image version, both 2.2.0 and latest, is critical because different versions of the image may contain different code and dependencies. By testing with both versions, we can determine if the bug is specific to a particular release or if it persists across multiple versions. This information helps narrow down the potential causes of the problem and focus on the relevant codebase.

The details about the Hetzner token, such as it being project-scoped and having Read & Write permissions, are also vital. Project-scoped tokens have specific restrictions compared to global tokens, and understanding these restrictions can help identify potential authorization issues. The Read & Write permissions ensure that the token should have the necessary privileges to perform the required actions, including removing the temporary SSH key. However, the fact that the authentication fails despite these permissions suggests that there might be a different underlying issue, such as how the token is being used or interpreted by the API. By collecting and analyzing this system information, developers can create a comprehensive picture of the environment in which the bug occurs. This holistic view is essential for identifying patterns, ruling out potential causes, and developing targeted solutions. It also ensures that the fixes are tested and validated in a representative environment, reducing the risk of encountering the same issue in production. In essence, detailed system information is the foundation for effective bug diagnosis and resolution, enabling a more efficient and reliable development process.

Additional Info

Here’s the full error snippet:

TASK [vitabaks.autobase.cloud_resources : Hetzner Cloud: Remove temporary SSH key 'ssh_key_tmp_hdkzcwn' from cloud (if any)] ***************************************************************
An exception occurred during task execution. To see the full traceback, use -vvv. The error was: ansible_collections.hetzner.hcloud.plugins.module_utils.vendor.hcloud._exceptions.APIException: unable to authenticate (unauthorized, 719348e023203785)
fatal: [localhost]: FAILED! => {"changed": false, "failure": {"code": "unauthorized", "details": null, "message": "unable to authenticate"}, "msg": "unable to authenticate (unauthorized, 719348e023203785)"}

PLAY RECAP *********************************************************************************************************************************************************************************
localhost                  : ok=7    changed=1    unreachable=0    failed=1    skipped=191  rescued=0    ignored=0

~

The snippet confirms the error occurs during the removal of the temporary SSH key, specifically within the vitabaks.autobase.cloud_resources Ansible task. The error message, unable to authenticate (unauthorized, 719348e023203785), clearly indicates an authentication problem. The unauthorized code provides a specific error identifier, which can be helpful for further debugging and tracking within the Hetzner Cloud API logs. The fatal: [localhost]: FAILED! message indicates that the task failure caused the entire playbook execution to halt. The recap section provides a summary of the playbook execution, showing that out of numerous tasks, one failed, and many were skipped due to the failure. This highlights the cascading effect of the authentication error, preventing the successful completion of the deployment process. Analyzing the error snippet in detail helps to pinpoint the exact location and nature of the problem, which is crucial for developing an effective solution. The error message's clarity allows developers to focus on the authentication process within the Ansible task, specifically the interaction with the Hetzner Cloud API during SSH key removal. This targeted approach is more efficient than a general investigation of the entire playbook or deployment process.

Furthermore, the error snippet's context within the Ansible task execution provides additional insights. The task name, Hetzner Cloud: Remove temporary SSH key 'ssh_key_tmp_hdkzcwn' from cloud (if any), indicates that the task is designed to remove the temporary SSH key if it exists. This implies that the task is idempotent, meaning it should not cause an error if the key is not present. Therefore, the authentication failure is likely not related to the key's existence but rather to the process of authenticating with the API to perform the removal. The inclusion of the (if any) clause in the task name also suggests that the task is non-critical, meaning that its failure should not necessarily halt the entire deployment. However, the fatal error message indicates that Ansible is treating this failure as critical, which might be a configuration issue within the playbook itself. By understanding these nuances, developers can explore different avenues for resolving the problem, such as adjusting the playbook's error handling or investigating the specific authentication mechanism used by the Ansible task. This comprehensive analysis ensures that the solution not only addresses the immediate authentication failure but also improves the overall robustness and reliability of the deployment process.

The fact that the token works via curl, but the CLI deploy fails (even though the UI deploy succeeds but lacks backup/S3 and PgBouncer options), points to a potential issue in how the CLI handles authentication specifically during the SSH key removal task. This discrepancy suggests that the problem is not with the token itself or the overall API connectivity, but rather with the way the CLI is using the token in this particular context. It could be related to how the token is passed to the API, how the request is formatted, or even a timing issue where the API call is made before the token is fully recognized by the system. The successful UI deployment further complicates the matter, as it implies that the underlying API functionality is working correctly. This means that the problem is likely confined to the CLI's execution environment or its internal processes. By focusing on the differences between the CLI and UI deployments, and by examining the specific steps the CLI takes to remove the SSH key, we can gain valuable insights into where the discrepancy lies. This targeted approach is crucial for identifying the root cause and developing a fix that addresses the specific issue within the CLI.

Repair Input Keyword

  • Why unable to authenticate when removing temporary SSH key on Hetzner Cloud via CLI?
  • What is the bug description?
  • What is the expected behavior?
  • What are the steps to reproduce the bug?
  • What is the installation method used?
  • What is the system information?
  • What is the full error snippet?

Conclusion

So, there you have it, guys! A deep dive into the authentication bug when removing temporary SSH keys on Hetzner Cloud via the CLI. We've covered the bug description, expected behavior, steps to reproduce, system info, and the full error snippet. Hopefully, this breakdown helps in finding a solution and getting those PostgreSQL HA clusters deployed smoothly. Stay tuned for more updates and happy deploying! ✨