Is it possible to have a running backup DHCP server
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This has to be possible right? I haven't had to ever look into this, but a conversation came up about the concern of what happens if we lose access to our DHCP server, and I thought that there has to be some kind of a backup mechanism...
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Windows does have a way to do this, but I've never set it up.
Unsure about Linux DHCP servers.
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@dafyre a redundant, ready and waiting DHCP server with existing leases etc. Right?
I was told there is no such thing, and thought it incredibly strange that there wasn't.
"So everyone in the world is only use 1 DHCP server per range... get real" was my thought.. but I have no idea what the solution is.
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Maybe what was meant was "there is no such thing here, in your org".
Which, then begs the question. Why not?
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Linux DHCP servers are often just using flat files which could be placed into a git repo or maybe rsynced to a backup machine. Now, you just need to wait for a failing server and start the service / daemon on the backup machine. Icinga with a custom check / action plugin could do this, for example.
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In Windows, it's set up as a Failover Cluster... (https://technet.microsoft.com/en-us/library/ee405263(v=ws.10).aspx) article is for 2008, but I'd expect something similar or totally different for 2012, lol.
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@DustinB3403 said in Is it possible to have a running backup DHCP server:
This has to be possible right? I haven't had to ever look into this, but a conversation came up about the concern of what happens if we lose access to our DHCP server, and I thought that there has to be some kind of a backup mechanism...
Of course. Like most things you can...
- Do it at the platform level.
- Do it at the OS level.
- If the app supports it, do it at the app level.
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@DustinB3403 said in Is it possible to have a running backup DHCP server:
Maybe what was meant was "there is no such thing here, in your org".
Which, then begs the question. Why not?
No because, who cares? Not important to have DHCP fail over. You can go a long time with zero impact. Getting a new DHCP Server up is SO trivial. You'd need a special case to justify running one just for DHCP.
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@scottalanmiller said in Is it possible to have a running backup DHCP server:
@DustinB3403 said in Is it possible to have a running backup DHCP server:
Maybe what was meant was "there is no such thing here, in your org".
Which, then begs the question. Why not?
No because, who cares? Not important to have DHCP fail over. You can go a long time with zero impact. Getting a new DHCP Server up is SO trivial. You'd need a special case to justify running one just for DHCP.
At my last job, we used a Linux one and I can count the number of times it had issues on one hand... and i was there 10 years.
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In Server 2012 failover cluster is pretty easy to set up.
If you have a lot of reservations, it's not as trivial to set one up from scratch, but if you can restore your server from backups quickly, that works.
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@thwr said in Is it possible to have a running backup DHCP server:
Linux DHCP servers are often just using flat files which could be placed into a git repo or maybe rsynced to a backup machine. Now, you just need to wait for a failing server and start the service / daemon on the backup machine. Icinga with a custom check / action plugin could do this, for example.
You can also do corosync and pacemaker between the two, but it's a million percent easier to just spin up from a saved snapshot.
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@stacksofplates said in Is it possible to have a running backup DHCP server:
@thwr said in Is it possible to have a running backup DHCP server:
Linux DHCP servers are often just using flat files which could be placed into a git repo or maybe rsynced to a backup machine. Now, you just need to wait for a failing server and start the service / daemon on the backup machine. Icinga with a custom check / action plugin could do this, for example.
You can also do corosync and pacemaker between the two, but it's a million percent easier to just spin up from a saved snapshot.
Exactly. This is the OS cluster method.
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Interesting. I did not know this was a thing but it makes sense.
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@wirestyle22 said in Is it possible to have a running backup DHCP server:
Interesting. I did not know this was a thing but it makes sense.
It's how we always did these things before we had platform level failover techniques.
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@wirestyle22 and it is still how things like NAS and SAN failover.
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Server 2012 (maybe R2?) added the ability to have a backup/failover DHCP server in the Windows world.
But this is a waste of time.
Make a backup of your DHCP server config manually if you are worried about the VM hosting the service going south but not being restored.
