You may encounter some errors during migration. The following table helps you troubleshoot and resolve them.

ErrorTroubleshooting 
Not enough disk spaceIncrease the disk space that is allocated to ElasticSearch.
Migration logs indicate a failure
  1. Analyse the logs of the particular index to identify the reason for the failure.
  2. Reinitiate the data migration. See Migrate Events Service Data Using the Cutover Strategy.
    The migration restarts from the last successful point.

Socket errors or server unavailable 

This occurs when the source or destination cluster is down. This can also happen if a node restarts during the migration process.

Ensure that the source and destination cluster is healthy, then reinitiate the migration steps.

migration_output_Final* or metadata_migration_output* file is not generated

This can happen because of runtime errors.

  1. Analyse the logs to identify the reason for the failure.
  2. If the issue is related to source or destination cluster health, ensure source and destination cluster is healthy.
  3. Reinitiate the data migration. See Migrate Events Service Data Using the Cutover Strategy.
    The migration restarts from the last successful point.
Destination cluster state is red due to node left before cutover
  1. Reset ElasticSearch Destination Cluster including data.
  2. Reset Migration.
  3. Reinitiate the data migration. See Migrate Events Service Data Using the Cutover Strategy.

Key Questions

Why Should I Create a New Cluster with New Nodes?

To ensure that you retain the Controller configuration during migration, we recommend that you create a new Events Service 23.x cluster with the same configuration as that of the Events Service 4.5.x cluster. This ensures that all data is migrated seamlessly to Events Service 23.x.

You must maintain the cluster till the migration is complete.

How to Minimise Data Inconsistency on the New Cluster?

Ensure that you repeat the delta migration commands till the delta in Events Service 4.5.x is minimum.

Use logs to determine how much time each iteration takes to migrate the delta. If the total time taken for the iteration is significantly lesser than the previous iterations, it indicates that the delta in Events Service 4.5.x cluster has reduced. You can stop the iterations if the last two iterations take almost the same time to migrate.

For example, if the iteration takes 30 seconds and the previous iteration also took almost 30 seconds, you can consider that the delta is at minimum. Reduce the time gap between delta migration and post cutover migration. It ensures that the data to migrate after cutover is minimum and therefore, there is minimal data inconsistency.

What Data Is Migrated by Using the Utility Tool?

The migration tool utility migrates the following Events Service data:

  • End User Monitoring
  • Database Visibility
  • Synthetic Monitoring
  • Analytics

However, the Controller data is not migrated.

What Should I do If the Migration Fails?

  1. Troubleshoot the issue.
  2. Reinitiate the migration steps.
    The migration restarts from the last successful point.

Can I Undo Any Changes During the Migration Process?

If you want to undo any changes during migration and start afresh, Reset the Migration.

What Is Wildcard CA and Why Do I Need It? 

A wildcard Certificate Authority (CA) refers to a type of SSL/TLS certificate that uses a wildcard character (*) in the domain name section of the certificate. SSL/TLS certificates ensure that the data exchanged between the browser and the web server is secure and private.

When a wildcard character is used in a certificate, it allows the certificate to cover not only a single domain, but all subdomains under a specific domain. For example, if you have a wildcard certificate for "*.example.com," it would secure www.example.com, mail.example.com, blog.example.com, and so on. You need not obtain and renew certificates for each subdomain individually.

How to Generate CA with Multiple DNS Names?

There are many tools and methods to generate a CA with multiple DNS names (also known as Subject Alternative Names or SANs). One common approach is to use OpenSSL. Generate a Certificate Signing Request certificate and submit it for CA validation.

You must have a valid SSL certificate signed by a valid Certificate Authority (such as, Symantec, Digicert).

Apply a new certificate generated and trusted by CA vendor for newly created Events Service 23.x cluster. Update the application load balancer to trust both certificates to ensure all components work seamlessly after migration cutover process.

How Do I Backup Data Before Starting ES8 Data Migration?

See Back Up Events Service Data.

How Long Does the Utility Take to Migrate Data from Events Service 4.5.x to 23.x?

The speed and time for the migration varies depending on the system configuration, such as CPU, storage, memory, and network capabilities.

Consider that you have an Events Service 4.5.x cluster in AWS m4.4x large(16 vCPU * 64 GB Memory) with six nodes and each node has the disk space of 2 TB. And, you have created the Event Service 23.x cluster with the same configuration. The utility takes 72 hours to migrate 7 TB data from Events Service 4.5.x to 23.x cluster.

Do I Need to Enable SSL and Business Journey in the Events Service 23.x Cluster?

We recommend you to mirror the Events Service 4.5.x configurations in the Events Service 23.x. If you have SSL and Business Journey enabled in Events Service 4.5.x, enable them in the Events Service 23.x cluster too.