Elasticsearch Error: Invalid license - Common Causes & Fixes

Brief Explanation

The "Invalid license" error in Elasticsearch occurs when the cluster detects an issue with the current license. This could be due to license expiration, incorrect license type, or license validation failures.

Common Causes

1. Expired license
2. Incorrect license type for the cluster setup
3. License file corruption
4. Mismatch between the license and cluster nodes
5. Network issues preventing license validation

Troubleshooting and Resolution Steps

1. Check the license status:

   GET /_license
   

2. Verify the expiration date and license type.

3. If expired, renew the license through Elastic's website or your account manager.

4. For incorrect license types, obtain the appropriate license for your cluster setup.

5. Ensure the license file is not corrupted by re-downloading it.

6. Verify that all nodes in the cluster are compatible with the current license.

7. Check network connectivity to ensure proper license validation.

8. Apply the new or corrected license:

   PUT /_license
   {
     "license": {
       "uid": "893361dc-9749-4997-93cb-802e3d7fa4xx",
       "type": "basic",
       "issue_date_in_millis": 1411948800000,
       "expiry_date_in_millis": 1914278399999,
       "max_nodes": 100,
       "issued_to": "customer",
       "issuer": "elasticsearch",
       "signature": "AAAAAwAAAA..."
     }
   }
   

9. Restart the Elasticsearch cluster if necessary.

Best Practices

• Set up license expiration alerts to avoid unexpected issues
• Regularly review your license status and needs
• Keep your account information updated for smooth license renewals
• Consider using license management tools for larger deployments

Frequently Asked Questions

Q: Can I use Elasticsearch without a license?
A: Yes, Elasticsearch offers a free and open Basic license with limited features. For advanced features, you'll need a paid license.

Q: How do I check my current license status?
A: You can check your license status by sending a GET request to the /_license endpoint.

Q: What happens if my license expires?
A: When a license expires, you may lose access to certain features, and in some cases, the cluster may stop accepting new data.

Q: Can I downgrade my license type?
A: Yes, you can downgrade your license, but be aware that some features may become unavailable.

Q: How long does it take for a new license to take effect?
A: New licenses typically take effect immediately, but you may need to restart your cluster in some cases for all changes to apply fully.