DNS management and apex domains

Using CNAME records helps prevent downtime during maintenance operations. But CNAME records can’t point to apex domains, so you need to set up a workaround. Available workarounds depend on your DNS provider.

CNAME records

Each site on Upsun is made up of a set of containers. To map incoming requests to the appropriate container, Upsun runs routers in each region. A router’s IP address can change in two cases:

• During an upgrade or maintenance operation, routers can be taken offline while changes are applied.
• During a region upscale or downscale, routers can be added or removed.

In such situations, using A records can cause downtime. A records map a domain to an IP address. When a router’s IP address changes, you need to manually update your A records. Your site remains offline until you do, or until the router is back from maintenance.

To prevent downtime, create CNAME records through your DNS provider. CNAME records map a domain to another. Set up your CNAME records to point at your project’s target URL. The DNS record for this target URL automatically resolves to the IP addresses of the routers in your project’s region. When a router’s IP address changes, the DNS record is automatically and immediately updated. This prevents downtime without intervention from you.

Note that CNAME records can’t point to apex domains. Check with your DNS provider if they offer workarounds.

Workarounds for apex domains

Although CNAME records can’t point to apex domains, most DNS providers offer workarounds. Contact your DNS provider and choose the option that works for you.

If you use a CDN, you likely already have a workaround in place, such as with Fastly and Cloudflare.

Custom records

Some DNS providers offer custom records such as ANAME, ALIAS or HTTPS records, which you can manage like CNAME records. But unlike CNAME records, these custom records can point to apex domains.

To use custom records, follow the instructions on how to set up a custom domain. When you come to configuring your DNS provider, instead of a CNAME record, add a custom record pointing from your domain to your project’s target URL.

Domain forwarding

If your DNS provider doesn’t support custom records, consider using domain forwarding.

If your domain is example.com, domain forwarding redirects all requests from example.com to www.example.com.

To use domain forwarding, follow these steps:

1. Make the www. version of your site the default (canonical) version and configure your app and routes to use the www subdomain as upstream.

2. Follow the instructions on how to set up a custom domain. When you come to configuring your DNS provider, instead of a CNAME record, add a record forwarding requests from YOUR_DOMAIN to www.YOUR_DOMAIN.

Redirection service

If your DNS provider doesn’t support custom records or domain forwarding, consider using a redirection service. If your domain is example.com, a redirection service uses an A record to redirect all requests from example.com to www.example.com.

To use a redirection service, follow these steps:

1. Make the www. version of your site the default (canonical) version and configure your app and routes to use the www subdomain as upstream.

2. Follow the instructions on how to set up a custom domain. When you come to configuring your DNS provider, instead of a CNAME record, add an A record pointing from your domain to the redirection service.

A records

If your DNS provider doesn’t support any other workaround, consider using A records, but only as a last resort. When you use A records, if a router’s IP address changes, you need to update your A records manually. Until you do, your site can appear offline because requests are lost.

To use A records, follow these steps:

1. Get the IP addresses of your project’s production environment.

2. Follow the instructions on how to set up a custom domain. When you come to configuring your DNS provider, instead of a CNAME record, add A records pointing from your domain to each of the IP addresses from step 1. When a request comes in, one of those IP addresses is used at random.