0

Basically, here is my need : Being able to specify an IP address in the DNS Zones of my 60+ domains, and have the ability to redirect this IP to another one (and change it when needed). I'm not the kind of "network guy", so a little help would.. well...help ! ;-)

I need this because I'm managing 2 distinct dedicated servers :

  • Server #1 : Production, with public IP #1.
  • Server #2 : Emergency, in case of disaster, with public IP #2.

All my domain names DNS zones are pointing to this Server #1 (production) with IP address #1.

When My Server #1 (production) will be down (in case of Disaster), I will need to redirect all the the domain names to the Server #2 (emergency). In this case, my plan is to do the following :

  1. Manually change the DNS zones of my 60+ domain names, for them to point to the IP #2 of the Server #2 (emergency)
  2. Wait for the DNS propragation delay

Is there any better way of doing this, allowing me to have my DNS Zones always pointing to an IP, and allowing me to change only single line to have this IP redirect to IP #1, or IP #2 when I need it ? WOuld I need to manage an "external" Windows Server only dedicated to this role ? (that would be costly).. Or odes any online service allows to do this ? (but at the cost of any latency that I must absolutely avoid) ?

Please note that the public IP is used in many of places on the Windows Server : IIS Web Server, Plesk configuration etc.

Additional info : If it can help, my DNS zones are managed by OVH.

AlexLaforge
  • 206
  • 1
  • 12

2 Answers2

1

You need to get another public IP (third one) to use in DNS records. This third IP will be assigned to active server.

You need to use some high-availability software to monitor the servers and assign this third IP (VIP) to it when the other one is not available. You need to configure the production server to be the favorite one (assigned VIP by default).

For Linux systems, you can use keepalived for this purpose as HA solution. For Windows environment, this post may help you (I am not expert in Windows servers).

Community
  • 1
Khaled
  • 35,688
  • 8
  • 69
  • 98
  • This goes far from what I need :) Instead of a truly active availability monitoring switching automatically, I am just looking for a simple way to manually change the IP routing. The post you propose is interesting but seems to involve ARR mapping/configuration that will be hard to maintain on all my different websites (some serve static content, others allow upload of large files or have SSL certificates, and this type of ARR routing in IIS will certainly lead to a lot of specific cases to care about.. I think that a manual DNS switch remains the best, despite the propagation delay.. – AlexLaforge Feb 28 '17 at 19:52
1

Hmmm - I think DNS is not really the way to go, because records need to propagate.

I don't know how long the consensus is this should take, but I generally tend to think 48 hours is a reasonable - not every DNS server will accept your specified TTLs, and there are some fairly deep hierarchies out in the wild, resolvers relying on resolvers relying on more resolvers some distance away from the authoritative servers.

Have you considered using some kind of load-balancer/CDN-like?

This would allow you to specify the load-balancer IP or CDN in DNS, and be able to deal with the backend config separately.

That isn't to everyone's taste, though, so one alternative would be a pair of dedicated front-ends, with CNAMEs for your domains, to allow round-robin between the two.

You can generally dump nginx or haproxy on something like that, and be OK (but if this isn't your area, a managed front-end might be better).

Check what OVH offers - this is a common need, and they may well be able to provide you more specific advice.

iwaseatenbyagrue
  • 3,588
  • 12
  • 22