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Redundancy: Failover.
| Posted by TheITAdvisory, 10-11-2009, 12:55 AM |
| Hello All,
We are moving to a new office, and in this office we are going to need to host new high availability web/mail/dns servers. I Know we need fail over, and I know how to build a fail over box.
Our setup;
1 server (for ease of explaining)
Business class cable (5 static IPs)
Fios for the secondary fail over line
DirectAdmin running on the server
main connection
ns1.company.com -> xxx.xxx.xxx.21
ns2.company.com -> xxx.xxx.xxx.22
company.com (shared IP) xxx.xxx.xxx.23
FIOS Backup:
ns3.company.com -> xxx.xxx.xxx.100
ns4.company.com -> xxx.xxx.xxx.101
company.com (shared IP) xxx.xxx.xxx.102
Now, I guess what I am asking is how is dns going to work? I mean what are we going to have to setup in directadmin? Just add the ns3 and ns4 w/ IP's in DA? How is the main shared IP going to work? Can you add another shared IP in DA to become primary if the main ISP goes down? We are using just one box. I Guess it's new to me to do this with a DA server. Usually I build failovers for inet access, that's it.
Sorry if it sounds like gibberish, it's late, and I am very tired.
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| Posted by TheITAdvisory, 10-11-2009, 01:10 AM |
| I Just want everything to failover automatically so we don't have to mess around with it.
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| Posted by DJMizt73, 10-11-2009, 02:21 AM |
| just curious ..does your FIOS line will also route your 5 static IPs (Business Cable) or are you using separate IPs for this upstream?
Have you thought about doing the failover at the router level and not at the host level?
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| Posted by TheITAdvisory, 10-11-2009, 02:23 AM |
| Business cable has 5 IP's and I believe FIOS will too.
When my business cable goes out, I want the fios to take over.
I want to do it at the router level, and not the host, but wont I need to configure the web server to reflect those new IPs from verizon?
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| Posted by UNIXy, 10-11-2009, 02:33 AM |
| I have experience with cPanel failover but I suspect DA is as rigid when it comes to making it work that way. You will need some custom httpd.conf entries as well DNS failover (easy part). By the way, is your secondary node in-office or located off-site?
Regards
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| Posted by TheITAdvisory, 10-11-2009, 02:36 AM |
| That's the thing. It's not failng over to another server. I need just IP failover, so if the Business cable goes offline, things will automatically failover and use the FiOS connection. ns3 and ns4 would be setup with the fios IP's.
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| Posted by UNIXy, 10-11-2009, 02:44 AM |
| DA comes with a script that can migrate domains to a set of new IP(s). For example, you could run the IP migration script based on a particular event (failure of business cable). The script should be under /usr/local/directadmin/scripts.
Regards
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| Posted by TheITAdvisory, 10-11-2009, 03:05 AM |
| Thanks. I am aware of this script. I was hoping to not have to do that .
How do the larger data centers do it? When a link goes down, they fail over, and you still use the same IP's, like nothing happened? Unless I am under a misunderstanding about how that all works?
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| Posted by TheITAdvisory, 10-11-2009, 10:56 AM |
| Anyone? It's just failing over to the same physical server.
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| Posted by UNIXy, 10-11-2009, 01:28 PM |
| That would be difficult to do with network failover (one server). It's going to be a lot of configuration hacks, which are probably unsupported by DA.
Network engineers implement network failover at the BGPv4 level. The heart of the failover consists of route re-distribution / re-advertising through a secondary or "failover" transit or AS exit to the rest of the Internet. This process has a delay between 5-20 minutes depending on the number of advertised routes and router processing power (router has to receive an updated list of internet routes again). It's hardly a real-time failover. It's a last resort solution.
Anyway, in your case, you could do name-based virtual hosts. make sure Apache is listening on 0.0.0.0.
Regards
Regards
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| Posted by Steven, 10-11-2009, 01:49 PM |
| Personally what I would do in this situation is...
Setup a box to act as a router (linux/freebsd can do it).
Put the Directadmin box in a NAT with the router
Have ips from both isps hit the NAT
Use a failover dns service such as dnsmadeeasy to fail over to fios when a failure on the cable line is detected.
This requires no special configuration on the da box and can act as a firewall.
All in all.. your not going to have the HA you can at a reputable datacenter such as Gigenet
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| Posted by hdsrob, 10-11-2009, 03:07 PM |
| In my experience with both cable and FiOS, I'd run the FiOS as the primary connection. The fiber has been far more reliable than cable ever was, and the upstream bandwidth on FiOS is far better than anything we ever had on cable.
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| Posted by DJMizt73, 10-11-2009, 03:36 PM |
| In this case i would do as Steven suggested ..move the failover on the router and not the host ..move your DNS outside (some registrar will provide free DNS) and just create a round robin entry. The drawback is the dns round-robin will still rely on the TTL of the A record so you maybe unreachable by those that cached the IPs from the failed ISP.
you can use an old pc laying around or you can get an appliance like a soekris or alix and just load something like monowall or pfsense.
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