The reindex.ssl.certificate_authorities setting in Elasticsearch controls the trusted certificate authorities (CAs) used for SSL/TLS connections during reindexing operations from remote clusters. It ensures secure communication when reindexing data from external Elasticsearch clusters that use SSL/TLS encryption.
- Default value: None
- Possible values: A list of paths to PEM-encoded CA certificate files
- Recommendations: Configure this setting when reindexing from remote clusters that use SSL/TLS with certificates signed by custom CAs
This setting is crucial for maintaining security when reindexing data from remote Elasticsearch clusters that use SSL/TLS encryption. By specifying trusted CAs, Elasticsearch can verify the authenticity of the remote cluster's SSL certificate, preventing man-in-the-middle attacks and ensuring data integrity during the reindexing process.
Example
To set the reindex.ssl.certificate_authorities, you can use the cluster settings API:
PUT /_cluster/settings
{
"persistent": {
"reindex.ssl.certificate_authorities": [
"/path/to/ca1.crt",
"/path/to/ca2.crt"
]
}
}
You might want to change this setting when:
- Reindexing from a remote cluster that uses a custom CA for its SSL certificates
- Updating the list of trusted CAs after changes in your infrastructure
The effect of this change is that Elasticsearch will trust SSL certificates signed by the specified CAs when establishing connections for remote reindexing operations.
Common Issues or Misuses
- Incorrectly specified file paths leading to connection failures
- Using expired or revoked CA certificates
- Forgetting to update the setting when remote cluster CAs change
Do's and Don'ts
- Do keep your CA certificates up-to-date
- Do use absolute file paths when specifying CA certificate locations
- Do ensure that the Elasticsearch process has read access to the specified certificate files
- Don't use self-signed certificates in production environments
- Don't share or expose your CA certificates unnecessarily
Frequently Asked Questions
Q: Can I use multiple CA certificates for remote reindexing?
A: Yes, you can specify multiple CA certificate file paths in the reindex.ssl.certificate_authorities setting.
Q: What happens if the CA certificate is not specified correctly?
A: If the CA certificate is not specified correctly or is invalid, the reindexing operation will fail with SSL handshake errors.
Q: Is this setting required for all reindexing operations?
A: No, this setting is only required when reindexing from remote clusters that use SSL/TLS with certificates signed by custom CAs.
Q: Can I use environment variables in the certificate file paths?
A: No, Elasticsearch does not support environment variable expansion in this setting. Use absolute file paths instead.
Q: How often should I update the CA certificates?
A: Update the CA certificates whenever they are renewed or when there are changes in the trusted CAs for your remote clusters. Regular reviews of your SSL configuration are recommended.
