Creating Mixed Cluster Tests With State-Transfer For OIDC Flows In Keycloak

This document outlines the need for and the methodology to create mixed cluster tests with state-transfer capabilities for OpenID Connect (OIDC) flows within Keycloak. These tests are crucial to ensure the smooth operation of Keycloak clusters during rolling upgrades, where different nodes within the cluster may be running different versions of the software. By simulating these scenarios, we can identify and address potential compatibility issues, ensuring no data loss or service interruption occurs during upgrades. This article will delve into the specifics of the testing procedure, the motivations behind it, and the importance of such tests in maintaining a robust and reliable Keycloak deployment.

Background and Motivation

Keycloak, a leading open-source Identity and Access Management solution, is often deployed in clustered environments to ensure high availability and scalability. In these setups, multiple Keycloak instances work together to serve authentication and authorization requests. A common maintenance task is upgrading the Keycloak version, which is typically done via a rolling update. This process involves upgrading nodes one at a time to minimize downtime. However, this introduces a period where the cluster operates in a mixed-version mode, with some nodes running the old version and others running the new version.

During a rolling upgrade, state-transfer mechanisms are critical. Keycloak uses Infinispan, a distributed caching solution, to share data between nodes. If the Infinispan patch version changes between Keycloak versions, compatibility issues can arise, potentially leading to data loss or inconsistencies. The existing clustered OIDC test, ClusteredOAuthClientTest, verifies OIDC flows in a fully formed cluster but does not account for the complexities of state-transfer during a rolling upgrade. This gap necessitates the creation of new tests that specifically address mixed-version scenarios to guarantee a seamless upgrade process. Ensuring state-transfer compatibility is paramount for the integrity and reliability of Keycloak clusters.

Problem Statement

The core challenge lies in verifying the correct behavior of OIDC flows during a rolling upgrade of a Keycloak cluster. The risk is that state-transfer incompatibilities between different Keycloak versions could disrupt OIDC flows, leading to authentication failures or data corruption. This scenario is not adequately covered by existing tests, which primarily focus on homogeneous clusters. The absence of specific tests for mixed-version clusters leaves a critical gap in our testing strategy. Therefore, it's imperative to develop tests that can effectively simulate and validate the state-transfer process during rolling upgrades, particularly concerning OIDC flows. This involves creating a test environment that accurately mimics a mixed-version cluster and executing OIDC flows to observe their behavior under these conditions. By identifying and addressing potential issues early, we can prevent disruptions during real-world upgrades.

Proposed Solution: Mixed Cluster Tests with State-Transfer

To address the identified gap, we propose creating a series of mixed cluster tests that specifically target state-transfer during rolling upgrades. These tests will simulate the scenario where a Keycloak cluster is undergoing a rolling upgrade, with nodes running different versions of the software. The primary goal is to ensure that OIDC flows continue to function correctly throughout the upgrade process. This approach provides a practical and effective way to validate the state-transfer mechanism and identify any compatibility issues between Keycloak versions. By simulating real-world upgrade scenarios, these tests offer a high degree of confidence in the reliability of the upgrade process. The tests will focus on the critical aspects of state-transfer, such as session replication, client registration, and user data synchronization, ensuring that these essential functions are not compromised during the upgrade.

The workflow of the proposed tests is as follows:

1. Initial Cluster Setup: Create a Keycloak cluster consisting of two nodes, denoted as [a, b], both running the initial version (v1) of Keycloak. This setup mirrors a typical clustered deployment before an upgrade.
2. Environment Configuration: Configure the cluster by creating realms, users, and other necessary entities. This step ensures that the cluster has a realistic dataset to work with, including OIDC clients and user accounts. The realms will represent different security domains, and the users will have various roles and permissions, reflecting the diversity of a real-world Keycloak deployment.
3. First Node Upgrade: Shut down node b and replace it with an instance running the target version (v2) of Keycloak. This creates a mixed-version cluster, represented as [a, b'], where a is running v1 and b' is running v2. This is a critical stage for testing state-transfer, as data needs to be synchronized between the two different versions.
4. OIDC Flow Verification (Stage 3): At this stage, initiate OIDC flows and ensure they work as expected. This involves testing various OIDC flows, such as authorization code flow, implicit flow, and hybrid flow, to cover different use cases. Interactions should be initiated at both nodes (a and b') to verify that requests are correctly handled regardless of which node receives them. This step is crucial to validate that the mixed-version cluster can correctly process authentication and authorization requests.
5. Second Node Upgrade: Shut down node a and replace it with an instance running the v2 version, resulting in a fully upgraded cluster [a', b']. This completes the rolling upgrade process.
6. OIDC Flow Verification (Stage 4): Repeat the OIDC flow verification process as in step 4. This ensures that the cluster functions correctly after all nodes have been upgraded. Interactions should be initiated at both nodes (a' and b') to confirm that the upgraded cluster is fully operational and that no issues have been introduced during the upgrade.

By following this workflow, the tests will provide comprehensive coverage of the rolling upgrade process, ensuring that OIDC flows remain functional and that state-transfer occurs seamlessly. This rigorous testing approach is essential for maintaining the reliability and security of Keycloak deployments.

Detailed Test Scenarios and Implementation

To ensure comprehensive testing, various OIDC flows should be tested at stages 3 and 4 of the workflow. These flows include:

• Authorization Code Flow: This is the most common and recommended OIDC flow, involving the exchange of an authorization code for an access token. It is crucial to test this flow thoroughly, as it underpins many web applications.
• Implicit Flow: This flow is simpler but less secure and is often used for single-page applications. Testing this flow ensures compatibility for legacy applications.
• Hybrid Flow: This flow combines aspects of both the authorization code flow and the implicit flow, offering a balance between security and simplicity. It is important to test this flow to cover a range of use cases.

For each flow, the following aspects should be verified:

• Authentication: Ensure that users can successfully authenticate against the cluster, regardless of which node they are directed to.
• Authorization: Verify that access tokens are correctly issued and that users are granted the appropriate permissions based on their roles.
• Session Management: Confirm that user sessions are correctly maintained and replicated across the cluster, even during the mixed-version phase.
• Token Handling: Validate that tokens are correctly refreshed, revoked, and validated throughout the OIDC flow.

In implementing these tests, it is essential to use an automated testing framework. This will allow for repeatable and consistent test execution, as well as easy integration with continuous integration and continuous deployment (CI/CD) pipelines. The tests should be designed to be easily configurable, allowing for different Keycloak versions and cluster configurations to be tested. The use of containers (e.g., Docker) is highly recommended, as it provides a consistent and isolated environment for each Keycloak instance. This approach simplifies the setup and teardown of the test environment and ensures that the tests are not affected by external factors.

The tests should also include detailed logging and reporting capabilities. This will make it easier to identify and diagnose any issues that arise during the tests. The logs should capture relevant information about the OIDC flows, such as request and response payloads, token contents, and session state. The reports should provide a clear summary of the test results, including any failures or errors that were encountered. This level of detail is crucial for effective debugging and ensures that any issues are promptly addressed.

Benefits and Expected Outcomes

The implementation of mixed cluster tests with state-transfer for OIDC flows will provide several significant benefits:

• Improved Upgrade Reliability: The tests will ensure that Keycloak upgrades can be performed with confidence, minimizing the risk of downtime or data loss.
• Early Issue Detection: By simulating mixed-version scenarios, the tests will identify compatibility issues early in the development cycle, allowing for timely fixes.
• Enhanced Security: The tests will help to ensure that OIDC flows remain secure during and after upgrades, protecting sensitive data and user identities.
• Increased Confidence: The tests will provide greater confidence in the stability and reliability of Keycloak deployments, particularly in clustered environments.

Expected outcomes from these tests include:

• Identification of State-Transfer Issues: The tests will uncover any potential issues with state-transfer between different Keycloak versions, particularly those related to Infinispan compatibility.
• Validation of OIDC Flow Functionality: The tests will confirm that OIDC flows continue to function correctly throughout the upgrade process, ensuring that authentication and authorization services remain available.
• Comprehensive Test Suite: The tests will contribute to a more comprehensive test suite for Keycloak, covering a critical aspect of cluster operations.

These outcomes will significantly enhance the quality and reliability of Keycloak, making it a more robust and dependable solution for identity and access management. The investment in these tests is a proactive measure that will pay dividends in the form of smoother upgrades, reduced downtime, and increased user satisfaction. Ultimately, the goal is to provide a seamless and secure experience for Keycloak users, even during complex operations such as rolling upgrades.

Conclusion

The creation of mixed cluster tests with state-transfer for OIDC flows is a crucial step in ensuring the reliability and stability of Keycloak clusters during rolling upgrades. These tests will provide valuable insights into the behavior of OIDC flows in mixed-version environments, allowing for the early detection and resolution of compatibility issues. By simulating real-world upgrade scenarios, these tests will give Keycloak administrators the confidence to perform upgrades without fear of disrupting authentication and authorization services. The proposed testing methodology, with its focus on detailed test scenarios, automated execution, and comprehensive reporting, will contribute to a more robust and resilient Keycloak platform. This investment in testing is essential for maintaining the high standards of quality and security that Keycloak users expect. The long-term benefits of these tests will be seen in reduced downtime, improved upgrade experiences, and enhanced overall system reliability.