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Moving Between CDN Providers

Moving Between CDN Providers

Switching between CDN (Content Delivery Network) providers is a significant operation, but with the right planning, it can be done smoothly, with zero downtime and full business continuity. Whether you're:

  • A new GlobalDots customer migrating to a new CDN,

  • An ex-customer transitioning away, or

  • A third-party handling your own transition,

this guide outlines key considerations and steps to ensure a successful switchover.

πŸ” Pre-Migration Checklist

βœ… Verify the Configuration

Different CDNs come with unique default behaviors, such as:

  • Cache duration settings

  • Gzip compression

  • Query string caching rules

These variations can lead to unexpected performance or behavior changes. It is essential to test the new CDN in a staging or limited-production environment before the full rollout. GlobalDots engineers assist our customers during this critical validation phase.

πŸ”§ Modify Your Web Code (If Needed)

If your setup uses CDN-provided domains like:

  • a123456.cloudfront.net

  • abc.akamaized.net

then changing CDNs means updating those links in your code.

Best Practice:

Use custom domain names (e.g., cdn.yourdomain.com) that act as CNAMEs to the CDN. This way, future CDN changes won’t require code updates.

πŸ” Prepare SSL Certificates

Depending on your CDN agreement, you may need to:

  • Upload your own SSL certificate, CA bundle, and private key, or

  • Approve inclusion of your domain in a CDN-managed SAN certificate (typically via an email to admin@yourdomain.com).

Ensure this is handled before final deployment to avoid HTTPS issues.

πŸ§ͺ Testing and Cutover Process

πŸ”„ Concurrent CDN Operation (Minimum 3 Days)

To ensure a smooth transition:

  • Keep both CDNs active simultaneously.

  • This buffers against slow TTL propagation and lingering traffic on the old CDN.

πŸ“‰ Reduce DNS TTL

Lower the TTL of your CNAME records to a few minutes 24–48 hours before switching. This allows for rapid rollback if needed.

πŸ“ˆ Prepare for Origin Server Load Spike

New CDN caches are cold. Expect a spike in origin traffic until cache warm-up completes. Make sure your backend can handle this temporary load.

πŸ” Perform the DNS CNAME Switch

Once everything is validated:

  • Point your custom CNAMEs to the new CDN.

  • Use your reduced TTL setting to monitor and, if needed, roll back quickly.

πŸ“Š Post-Migration Monitoring

πŸ‘€ Monitor New CDN

Watch for:

  • 4xx errors (usually misconfigurations)

  • 5xx errors (origin or connectivity issues)

Leverage GlobalDots monitoring tools to identify and resolve issues quickly.

🧭 Monitor Old CDN

Confirm that traffic is tapering off. Persistent traffic may indicate:

  • Clients ignoring DNS TTLs

  • Hardcoded references to old CDN hostnames

Investigate and update as necessary.

⏱️ Restore DNS TTL to Normal

Once the new CDN is stable and traffic patterns are normal:

  • Increase TTL to improve caching and reduce DNS query costs.

πŸŽ‰ Final Note

Congratulations on completing your CDN migration! With these steps, you’ve ensured minimal disruption and maximum performance continuity. If you’re a GlobalDots customer, our engineers are here to guide you through every stage.