Podman Secret Removal Issue: Missing Storages

Dec 3, 2025 by Alex Johnson 46 views

Introduction

In this comprehensive guide, we'll delve into a peculiar issue encountered while using Podman, a powerful container management tool. Specifically, we'll address the problem of failing to remove secrets when the inspected storages, particularly those associated with the pass driver, no longer exist. This issue can be quite frustrating, especially when you need to clean up and manage your secrets effectively. We will explore the root cause of this problem, provide a step-by-step guide to reproduce it, and discuss potential solutions and workarounds. By the end of this article, you'll have a solid understanding of this Podman secret removal issue and how to tackle it.

Understanding the Podman Secret Removal Issue

When working with Podman, you might encounter a scenario where you're unable to remove a secret that was initially created using the --driver=pass option. This typically occurs when the gnupg and password-store storages, which are essential for managing secrets with the pass driver, are no longer present. In essence, Podman loses the necessary context to perform the removal operation, leading to a failure. This can be a significant issue, especially in environments where secrets are frequently created and removed as part of automated processes or testing.

The problem arises because Podman relies on the underlying storage directories to manage the lifecycle of secrets. When these directories are deleted or become inaccessible, Podman is unable to locate and remove the secret, resulting in an error. The error message typically indicates that the secret cannot be removed because the necessary storage components are missing. This behavior can lead to a buildup of orphaned secrets, which can clutter your system and potentially pose a security risk if not properly addressed.

To better understand this issue, let's consider a practical example. Imagine you're developing an application that uses secrets to access external resources. You create a Podman secret using the pass driver, store it securely, and then deploy your application. Later, you decide to remove the secret, but in the meantime, the storage directories associated with gnupg and password-store have been deleted or moved. When you attempt to remove the secret using podman secret rm, the operation fails because Podman cannot locate the necessary storage information. This leaves the secret in a state of limbo, neither accessible nor removable, which can be problematic for system administrators and developers alike.

Reproducing the Issue: A Step-by-Step Guide

To fully grasp the Podman secret removal issue, it's helpful to reproduce it in a controlled environment. The following steps outline how to reproduce this issue using nested Podman containers, providing a safe and isolated testing ground.

Set up the Environment: Begin by setting up a Podman environment where you can create and manage containers. If you're using a Linux system, you can install Podman using your distribution's package manager. For example, on Fedora, you can use the command sudo dnf install podman.
Run a Privileged Container: Execute a privileged Podman container using the following command:

podman run -it --rm --privileged secret-test /bin/bash ```

This command launches a new container named `secret-test` in interactive mode with elevated privileges, allowing you to perform the necessary operations to reproduce the issue.

Create a Test Script: Inside the container, create a bash script named /tmp/proof.sh with the following content:

#!/usr/bin/env bash
set -e

pushd $(pwd) > /dev/null
trap "popd > /dev/null" EXIT

# Podman secret name
PODMAN_SECRET_NAME="${1:-driver_pass_test}"

# GPG key ID used by `pass`

GPG_KEY_EMAIL="local@local.secret" ## Name for the new key if the ID does not exist GPG_KEY_NAME="Podman Secret"

# Configure `gpg`: GPG key directory (will be created if it does not exist)
GNUPGDIR="$(pwd)/.gnupg-podman"

# Configure `pass`:
## `pass` storage directory (sub-dir "podman"). (will be created if it does not exist)
PASSWORD_STORE_DIR="$(pwd)/.password-store-podman/podman"
## `gpg` options used by `pass` when getting keys
PASSWORD_STORE_GPG_OPTS="--homedir $GNUPGDIR"

# Export for `pass` usage
export PASSWORD_STORE_DIR
export PASSWORD_STORE_GPG_OPTS

# gpg wrapper with --homedir

gpg() { command gpg --homedir " $GNUPGDIR" "$ @" }

# Create example credentials file
cat << EOF > "$(pwd)/cred-example.json"
{
  "id": 1,
  "pass": "secret_pass"
}
EOF

# Ensure the GPG key exists (create if necessary)
if ! gpg --list-keys "$GPG_KEY_EMAIL" &>/dev/null; then
  mkdir -m 700 "$GNUPGDIR"
  # These options set a blank password and inhibit the prompt: --batch --yes --pinentry-mode loopback --passphrase ""
  if gpg --batch --yes --pinentry-mode loopback --passphrase "" --quick-gen-key "$GPG_KEY_NAME <$GPG_KEY_EMAIL>"; then
    echo "Key successfully created in $GNUPGDIR"
  fi
else
  echo "Key already exists for $GPG_KEY_EMAIL in $GNUPGDIR"
fi

# Ensure `pass` storage exists
if ! pass ls &> /dev/null; then
  # The PASSWORD_STORE_DIR directory will be created if it does not exist
  # Initialize the `pass` storage, assigning a "gpg-id" to a specific "podman" sub-storage
  pass init "$GPG_KEY_EMAIL" 2> /dev/null
fi

# Create a podman secret protected by `pass` (--driver=pass) from the credentials file.
# The `pass` driver considers the GNUPGDIR and PASSWORD_STORE_DIR settings for the GPG_KEY_EMAIL key
podman secret create --replace --driver=pass \
  "--driver-opts=root=$PASSWORD_STORE_DIR" \
  "--driver-opts=gpghomedir=$GNUPGDIR" \
  "--driver-opts=key=$GPG_KEY_EMAIL" \
  "$PODMAN_SECRET_NAME" /tmp/cred-example.json

# End of script
```

This script automates the process of creating a secret using the `pass` driver.

Make the Script Executable: Grant execute permissions to the script using the command:
```
chmod +x /tmp/proof.sh
```
Install Dependencies: Install the necessary packages within the container using the following commands:

dnf install -y podman pass gnupg2 pinentry sudo tee /etc/containers/storage.conf > /dev/null << EOVFS [storage] driver = "vfs" EOVFS podman system reset -f ```

These commands install Podman, the `pass` utility, GnuPG, and other dependencies required for the test.

Prepare the Tests: Navigate to the /tmp directory and create two secrets using the script:
```
cd /tmp
./proof.sh "secret-1" > /dev/null
./proof.sh "secret-2" > /dev/null
```
This will create two secrets, secret-1 and secret-2, using the pass driver.
Run the Tests: Execute the following commands to test the secret removal functionality:

echo; echo ".......... Tests .........."; echo

podman secret exists "secret-1" && log_success "Secret exists: secret-1" || log_error "Secret not exists: secret-1 " podman secret rm "secret-1" &> /dev/null && log_success "Can remove secret: secret-1" || log_error "Can not remove secret: secret-1" ! podman secret exists "secret-1" && log_success "Secret no more exists: secret-1" || log_error "Secret still exists: secret-1"

podman secret exists "secret-2" && log_success "Secret exists: secret-2 " || log_error "Secret not exists: secret-2 " rm -rf /tmp/.gnu* /tmp/.pass* > /dev/null && log_success "Success to remove: /tmp/.gnu* /tmp/.pass*" || log_error "Fail to remove: /tmp/.gnu* /tmp/.pass*" podman secret rm "secret-2" &> /dev/null && log_success "Can remove secret: secret-2" || log_error "Can not remove secret: secret-2" ! podman secret exists "secret-2" && log_success "Secret no more exists: secret-2 " || log_error "Secret still exists: secret-2 " ```

These commands perform the following actions:

*   Check if `secret-1` exists and remove it.
*   Check if `secret-2` exists.
*   Remove the `gnupg` and `password-store` directories.
*   Attempt to remove `secret-2`.
*   Verify if `secret-2` still exists.

Observe the Results: You'll notice that while secret-1 is successfully removed, the removal of secret-2 fails after the storage directories are deleted. This demonstrates the Podman secret removal issue.

By following these steps, you can reproduce the issue and observe the behavior firsthand. This understanding is crucial for developing effective solutions and workarounds.

Expected vs. Actual Results

When attempting to remove a Podman secret after the associated storage directories have been deleted, the expected outcome is that the secret should be successfully removed. However, the actual result often deviates from this expectation. Let's break down the expected and actual results to better understand the issue.

Expected Results

In an ideal scenario, the sequence of operations and their expected outcomes would be as follows:

Secret Exists: Verify that the secret exists in Podman's secret store. The expected result is that the secret is found and confirmed to exist.
Remove Secret: Attempt to remove the secret using the podman secret rm command. The expected result is that the command executes successfully, and the secret is removed from Podman's secret store.
Secret No Longer Exists: After the removal attempt, verify that the secret no longer exists in Podman's secret store. The expected result is that the secret is not found, confirming its successful removal.

Actual Results

However, the actual results when the storage directories are missing paint a different picture:

Secret Exists: The secret is initially found to exist in Podman's secret store, as expected.
Remove Secret Fails: The attempt to remove the secret using the podman secret rm command fails. This is the core of the issue. Podman is unable to remove the secret because the necessary storage directories (i.e., gnupg and password-store) are missing.
Secret Still Exists: After the failed removal attempt, the secret still exists in Podman's secret store. This indicates that the removal operation was unsuccessful, and the secret remains orphaned.

This discrepancy between the expected and actual results highlights the problem. The inability to remove secrets when storage directories are missing can lead to several issues, including orphaned secrets, potential security vulnerabilities, and difficulties in managing secrets effectively.

Analyzing the Root Cause

The root cause of the Podman secret removal issue lies in the way Podman's pass driver manages secrets and its dependency on the underlying storage directories. To fully understand the issue, let's break down the key components and how they interact.

Podman Secrets and Drivers

Podman uses a driver-based architecture to manage secrets. The driver is responsible for storing, retrieving, and removing secrets. The pass driver, specifically, leverages the pass utility, which in turn uses GnuPG (GNU Privacy Guard) to encrypt and store secrets. This setup provides a secure way to manage sensitive information, but it also introduces dependencies on external tools and storage locations.

The Role of `gnupg` and `password-store`

The pass utility relies on two primary storage locations:

gnupg Directory: This directory (~/.gnupg by default) stores GPG keys and configuration files. GPG keys are used to encrypt and decrypt secrets, ensuring their confidentiality.
password-store Directory: This directory (~/.password-store by default) stores the encrypted secrets themselves. The pass utility organizes secrets in a hierarchical directory structure within this location.

When a secret is created using the pass driver, Podman instructs the pass utility to store the secret in the password-store directory, encrypted using a GPG key from the gnupg directory. The metadata about the secret, including its name and driver-specific options, are stored within Podman's internal database.

The Removal Process

When a secret is removed using podman secret rm, Podman attempts to use the driver to delete the secret. In the case of the pass driver, this involves the following steps:

Lookup Metadata: Podman retrieves the metadata associated with the secret from its internal database. This metadata includes the driver type (pass) and any driver-specific options, such as the paths to the gnupg and password-store directories.
Invoke pass Utility: Podman invokes the pass utility to delete the secret. It passes the necessary parameters, including the secret name and the storage directory paths.
Storage Dependency: The pass utility then attempts to delete the secret from the password-store directory. However, if the gnupg or password-store directories are missing or inaccessible, the pass utility will fail, and Podman will be unable to remove the secret.

The Core Issue

The core issue arises because Podman's secret removal process with the pass driver is tightly coupled with the existence and accessibility of the gnupg and password-store directories. If these directories are removed or become inaccessible after the secret is created, Podman loses the necessary context to perform the removal operation. This dependency creates a vulnerability where secrets can become orphaned and unremovable, leading to potential management and security challenges.

Potential Solutions and Workarounds

Addressing the Podman secret removal issue requires a combination of understanding the root cause and implementing appropriate solutions and workarounds. While there isn't a single magic bullet, several strategies can help mitigate the problem and ensure effective secret management.

1. Preventative Measures: Ensuring Storage Persistence

The most straightforward approach to avoid this issue is to prevent the storage directories from being inadvertently deleted or moved. This involves implementing policies and procedures to ensure the persistence of the gnupg and password-store directories.

Backup and Restore: Regularly back up the gnupg and password-store directories. In case of accidental deletion or corruption, these backups can be used to restore the storage directories, allowing Podman to remove the secrets.
Persistent Storage: Consider using persistent storage volumes for the gnupg and password-store directories. This ensures that the directories are not lost when containers are stopped or removed. Persistent volumes can be mounted to containers, providing a stable storage location for secrets.
Access Controls: Implement strict access controls on the storage directories. Limit access to authorized users and processes only, reducing the risk of accidental or malicious deletion.

2. Manual Removal: A Hands-On Approach

In situations where the storage directories are missing, manual removal of the secret may be necessary. This involves directly interacting with the pass utility and Podman's internal database.

Recreate Storage: If possible, recreate the gnupg and password-store directories. This may involve restoring from a backup or reinitializing the pass storage. Once the directories are in place, Podman should be able to remove the secret.
Manual Deletion with pass: If recreating the storage is not feasible, you can attempt to manually delete the secret using the pass utility. This involves identifying the secret's entry in the password-store directory and deleting the corresponding file.
Database Cleanup: In some cases, metadata about the secret may remain in Podman's internal database even after the storage is gone. You may need to manually clean up the database to remove these orphaned entries. This typically involves using Podman's API or command-line tools to inspect and delete secrets.

3. Error Handling: Graceful Failure and Recovery

Robust error handling can help manage the issue more gracefully. This involves implementing checks and recovery mechanisms in your scripts and applications.

Check for Storage: Before attempting to remove a secret, check if the gnupg and password-store directories exist and are accessible. If not, log an error or implement an alternative removal strategy.
Retry Mechanism: Implement a retry mechanism that attempts to remove the secret multiple times. This can help in cases where the storage directories are temporarily unavailable.
Fallback Strategy: If removal fails, consider a fallback strategy, such as logging the secret and its metadata for manual removal later.

4. Podman Enhancements: Potential Future Improvements

Ultimately, a long-term solution may involve enhancements to Podman itself. The Podman community is actively working on improving secret management, and future releases may include features to address this issue.

Force Removal: A --force option for the podman secret rm command could allow users to forcibly remove secrets even if the storage directories are missing. This would provide a way to clean up orphaned secrets.
Driver Independence: Decoupling the secret removal process from the storage directories could make Podman more resilient to this issue. This might involve storing additional metadata about the secret within Podman's internal database, allowing it to remove secrets even if the storage is gone.
Storage Management: Improved storage management features within Podman could help prevent the accidental deletion of storage directories. This might include features like automatic backups or alerts when storage is at risk.

Is there no way to force removal (`--force` ...?)?

As of now, Podman does not offer a --force option or similar mechanism to forcibly remove secrets when the underlying storage directories are missing. This limitation is a key aspect of the issue we've been discussing. The absence of a force removal option means that when Podman loses access to the gnupg and password-store directories, it cannot proceed with the secret removal operation, leading to the problem of orphaned secrets.

However, the need for such a feature has been recognized by the Podman community, and there is ongoing discussion about potential improvements in future releases. A --force option would provide a way to bypass the storage dependency, allowing users to clean up secrets even when the storage context is lost. This would be a valuable addition to Podman's secret management capabilities, enhancing its robustness and ease of use.

In the meantime, users are limited to the workarounds and manual methods described earlier, such as recreating the storage directories or manually deleting the secret entries. While these methods can be effective, they require additional effort and may not be suitable for all situations. The potential introduction of a --force option in future Podman versions represents a significant step towards addressing this issue and providing a more seamless secret management experience.

Conclusion

The Podman secret removal issue, which arises when inspected storages are missing, presents a notable challenge in container management. This article has explored the intricacies of this issue, providing a detailed understanding of its root cause, steps to reproduce it, and a range of potential solutions and workarounds. By ensuring storage persistence, employing manual removal techniques, implementing robust error handling, and anticipating future Podman enhancements, you can effectively mitigate this problem.

The absence of a --force option in the current version of Podman underscores the need for proactive secret management strategies. However, the ongoing discussions within the Podman community signal a commitment to addressing this limitation in future releases. As Podman continues to evolve, we can expect to see more robust and user-friendly secret management capabilities.

By staying informed and adopting best practices, you can ensure that your secrets are not only securely stored but also effectively managed throughout their lifecycle. Remember to always prioritize the security and integrity of your secrets, and choose the solutions that best fit your specific environment and requirements.

For more in-depth information on Podman secrets and best practices, refer to the official Podman documentation and community resources. Podman Documentation often provides the most up-to-date information and guidance on using Podman features.