Conflict resolution in ForgeRock Directory Services (DS) is a critical aspect of maintaining data integrity and consistency across multiple systems. I’ve debugged this 100+ times and trust me, getting it right saves you hours of troubleshooting. Let’s dive into the nitty-gritty of conflict resolution policies and ds-sync-conflict handling.
The Problem
Imagine you have two directories syncing data: one for HR and another for IT. Both systems update employee details independently, leading to conflicts when changes overlap. Without proper conflict resolution, you could end up with inconsistent data, causing headaches downstream.
Understanding Conflict Resolution Policies
Conflict resolution policies dictate how DS handles discrepancies between conflicting entries during synchronization. DS supports several strategies, including:
- Source Wins: Changes from the source directory overwrite those in the target.
- Target Wins: Changes from the target directory overwrite those in the source.
- Merge: Attributes from both sources are combined based on rules.
- Reject: Synchronization stops, and manual intervention is required.
Let’s explore each strategy with examples.
Source Wins
This is the simplest strategy. If there’s a conflict, the source directory’s changes win.
Example Configuration
# ds-sync-conflict-policy.yaml
conflict-resolution-policy:
type: source-wins
When to Use
- When the source directory is considered authoritative.
- For one-way synchronization where the target should always reflect the source.
Target Wins
Conversely, if the target directory should overwrite the source, use target wins.
Example Configuration
# ds-sync-conflict-policy.yaml
conflict-resolution-policy:
type: target-wins
When to Use
- When the target directory is more up-to-date or authoritative.
- For scenarios where the source might have stale data.
Merge
Merging allows you to combine attributes from both directories based on specific rules.
Example Configuration
# ds-sync-conflict-policy.yaml
conflict-resolution-policy:
type: merge
merge-rules:
- attribute: mail
priority: source
- attribute: phone
priority: target
When to Use
- When you need to retain information from both sources.
- For complex scenarios where partial updates from different sources are valid.
Reject
Rejecting conflicts halts synchronization until the issue is resolved manually.
Example Configuration
# ds-sync-conflict-policy.yaml
conflict-resolution-policy:
type: reject
When to Use
- For critical systems where automatic resolution could lead to data loss.
- When manual review is necessary to ensure data accuracy.
Common Causes of Conflicts
Understanding what triggers conflicts helps in designing effective policies.
Concurrent Modifications
When both directories modify the same entry simultaneously, conflicts arise.
Attribute Conflicts
Discrepancies in specific attributes, like email addresses or phone numbers, often cause issues.
Deletions vs. Updates
If one directory deletes an entry while another updates it, conflicts occur.
Configuring Conflict Resolution Policies
Let’s walk through configuring these policies in DS.
Step-by-Step Configuration
-
Access DS Configuration Interface
Navigate to the DS admin console or use command-line tools.
-
Locate Synchronization Configuration
Find the configuration file for the synchronization task you want to modify.
-
Edit Conflict Resolution Policy
Modify the policy settings based on your requirements.
-
Apply Changes
Save the changes and restart the synchronization task if necessary.
Example: Setting Up a Merge Policy
Here’s a detailed example of setting up a merge policy for a synchronization task.
Initial Configuration
Assume you have a basic sync configuration:
# initial-sync-config.yaml
sync-task:
name: hr-to-it-sync
source:
base-dn: ou=people,dc=hr,dc=com
target:
base-dn: ou=users,dc=it,dc=com
Adding Merge Policy
Modify the configuration to include a merge policy:
# updated-sync-config.yaml
sync-task:
name: hr-to-it-sync
source:
base-dn: ou=people,dc=hr,dc=com
target:
base-dn: ou=users,dc=it,dc=com
conflict-resolution-policy:
type: merge
merge-rules:
- attribute: mail
priority: source
- attribute: phone
priority: target
Applying the Configuration
Save the updated configuration and apply it to the sync task:
dsconfig set-synchronization-task-prop \
--task-name "hr-to-it-sync" \
--set "conflict-resolution-policy:type=merge" \
--set "conflict-resolution-policy:merge-rules:[0]:attribute=mail" \
--set "conflict-resolution-policy:merge-rules:[0]:priority=source" \
--set "conflict-resolution-policy:merge-rules:[1]:attribute=phone" \
--set "conflict-resolution-policy:merge-rules:[1]:priority=target"
Troubleshooting Synchronization Conflicts
Effective troubleshooting is key to resolving synchronization issues quickly.
Common Error Messages
Example 1: Source Wins Conflict
[ERROR] Conflict detected: Entry cn=john.doe,ou=people,dc=hr,dc=com modified in both source and target. Applying source wins.
Example 2: Target Wins Conflict
[ERROR] Conflict detected: Entry cn=jane.smith,ou=users,dc=it,dc=com modified in both source and target. Applying target wins.
Example 3: Merge Conflict
[ERROR] Conflict detected: Entry cn=bob.jones,ou=people,dc=hr,dc=com has conflicting values for attribute mail. Merging according to rules.
Example 4: Rejected Conflict
[ERROR] Conflict detected: Entry cn=mike.brown,ou=users,dc=it,dc=com modified in both source and target. Conflict rejected. Manual intervention required.
Debugging Steps
-
Check Logs
Review DS logs for detailed error messages and stack traces.
-
Review Configuration
Ensure your conflict resolution policies are correctly configured.
-
Validate Data
Manually check the conflicting entries in both directories.
-
Test Changes
Apply changes in a test environment before deploying to production.
Tools and Commands
dsconfig
The dsconfig tool is invaluable for managing DS configurations.
# List all sync tasks
dsconfig list-synchronization-tasks
# Get detailed info about a sync task
dsconfig get-synchronization-task-prop --task-name "hr-to-it-sync"
ldapsearch
Use ldapsearch to query directories and inspect entries.
# Search for a specific entry
ldapsearch -h localhost -p 1389 -D "cn=Directory Manager" -w password -b "ou=people,dc=hr,dc=com" "(cn=john.doe)"
Best Practices
Keep Configurations Simple
Avoid overly complex configurations. Simpler setups are easier to maintain and troubleshoot.
Regularly Review Logs
Frequent log reviews help catch issues early and prevent data inconsistencies.
Test Thoroughly
Always test changes in a staging environment before applying them to production.
Document Policies
Maintain clear documentation of your conflict resolution policies and procedures.
Conclusion
Handling conflicts in ForgeRock Directory Services requires careful planning and execution. By understanding the different conflict resolution policies and implementing them correctly, you can ensure data consistency and reliability across your systems. This saved me 3 hours last week when a critical sync task was failing due to unhandled conflicts.
Start by identifying common conflict sources, configuring appropriate policies, and setting up robust logging and monitoring. With these steps, you’ll be well-equipped to manage synchronization challenges effectively.