Manual Failover Settings

dash-dns
#1

Please excuse my inexperience. I have two servers with mirror sites - I have this for fail-over when one server has an outage. My experience with changing A-records is that some ISP’s take ages to update and so I get issues with different people seeing different things - so changing A Records does not do it.

I know CF has load balancing/auto fail-over but my question is - can I set-up DNS to have two servers in a way that allows me to switch between them with zero propagation in CF - immediate switch for everyone to see? Basically this is manual fail-over.

Thanks.

AJB

#2

If you really want to do it manually, set the TTL to 2 minutes. You can change the IPs manually on the fly. Almost.

You could also point your domain to two different IPs, you just need to ensure to delete the record of a failed service immediately.

Some programming knowledge might help to automate this process. In case server A fails, a script could change the destination IP via the API.

But I’d recommend to use Cloudflare LB if you want your service HA at 24/7.

2 Likes
#3

Hey Mark - thanks for the info. I have a fundamental question. Do ISP’s etc. cashe only the DNS name (bob.cloudflare.com) or the entire zone record (a, mx, ftp etc. etc.)?

I recently changed an a-record (on another DNS manager) without changing DNS and one client in mid-west took 3 days to see the new server. I saw it in 30 minutes - so TTL was different for users.

The reason I ask is that if TTL is set at 2 minutes, but my client in Tulsa’s ISP only updates every 3 days - it wouldn’t work for failover. the ISP in Tulsa only cashes the DNS (point to CloudFlare) and this doesn’t change, there’s no issue as CF can change the IP’s in 2 minutes and all is good.

Sorry to be a pest - I would love to understand this better. Even a link to a properly explained page would be great.

A.

#4

Each record separately, not the entire zone.

Who needs standards? :roll_eyes:

Cloudflare could be an advantage here. If your DNS records are set to :orange: they will show Cloudflare addresses to their visitors which usually only change depending on the location. You can’t change the TTL for orange clouded records and IIRC they are set to two or three minutes by default.
In this case, the TTL is ‘internal’ and a visitor or their ISPs wouldn’t recognize the change in the background. And they don’t need to.

Meh. Don’t do this again! :slight_smile:

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closed #5

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