It is not automated, because it requires that your servers perform specific, coordinated actions under conditions of your choosing. Linode gives you the ability to do it, you just have to do it when the time is right. (Something like Heartbeat and Pacemaker can automate this nicely.)

Also, you'd want to shut the "main server" down before bringing it up on the standby server, since all hell breaks loose if the same IP is on two servers at once. Also, it can help to originate a packet or two from the failed-over IP address, since routers tend to cache IP-to-MAC mappings for some time.

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I mean the re-pointing of the IP address to the new server is automatic, once the main server shuts down? Or is that why I run the command "ip addr add"? I didn't run this. Or is adding it to eth0:0 like this OK and rebooting? https://library.linode.com/networking/c ... interfaces

And to confirm, I assume when the main one comes back up I should remove the Ip address from the standby server again? As you say, you cant have multiple servers using the same IP? If this is true then thats a shame, I was hoping I could leave them in there. I was hoping a failover could work if the server goes down for unplanned maintenance without me doing anything.

Thanks

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Web Development Agency in South Wales

It's just like having two servers on a traditional Ethernet network: they can't both have the same IP address at the same time. An IP address maps to exactly one MAC address.

If you want more than one server sharing an IP address... well, that's what Nodebalancers are for. If it were as easy as just setting up the same IP address on two different servers, then Nodebalancers wouldn't need to exist...

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No I understand thats fine. Setting up the failover will still be much quicker than messing with DNS manually. I shall give it a go next time I think.

May I ask one more question... do you know if I need to reboot the standby server in question? So when I shutdown the main linode, and add the IP address to the standby one, do I need to reboot that one? Just trying to estimate downtime as it sounds like there will be downtime between the IP address being re-assigned.

Thanks

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Web Development Agency in South Wales

No reboot is necessary -- any Linode that is set up to bring that IP up can bring it up at any time, as long as no more than one Linode has it at any time.

I'd recommend firing up a couple Linodes and practicing...

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