Hello, I have been reading up on cloudmin and found that it has a feature to start a virtualmin instance if current instance is overloaded. Would I also be able to use this to migrate all traffic to a second Virtualmin instance should the first fail? What I am trying to accomplish is to have some sort of fail over and/or possibly a load balance scenario for my Virtualmin domains. I have already moved the necessary MySQL DB's to separate hardware to allow replication. Also, Since CentOS does not have drivers for the motherboard RAID that I am using in my Xen servers (running OpenSuSE 12.1) will cloudmin function as a guest on an existing XEN host? I could get new hardware to run cloudmin but would prefer not to as I already have several servers running XEN. Thank You, JohnM
Howdy,
Cloudmin has two different features in that regard.
If you have a shared storage devices, such as a SAN, you can put your VM images on that SAN... and if the server itself ever dies, Cloudmin can launch the VM using a different server. That's described here:
http://www.virtualmin.com/documentation/cloudmin/vm/failover
Alternatively, if you have two systems that are kept in sync, you can use Cloudmin's RoundRobin feature. You would tell Cloudmin about all the RoundRobin hosts... and would describe what conditions Cloudmin should remove a host from the RoundRobin group. That feature is described here:
http://www.virtualmin.com/documentation/cloudmin/vm/roundrobin
Cloudmin can work with no problem on a guest of another host. The only question would be how you hope to use it... I don't know that you'd be able to use Cloudmin to create a Xen guest within the Xen guest.
But, Cloudmin within a Xen guest can control other systems with no problem.
-Eric
Thank You for the response Eric, this is great news. As far as creating a Xen guest withing a Xen guest, i will not be trying that.
So, just for my clarification, I should create a master and slave cloudmin so that it is not a single point of failure, build my two Virtualmin servers using shared storage, and then round robin the virtualmins through cloudmin, Correct?
As a follow up, I currently have a license for Virtualmin for 50 domains, my assumption is I will need to get a second similar license for the second virtualmin. With Cloudmin I am not sure if I will need to ten instance licenses to start or if one ten instance license will cover the master and the slave cloudmin? The boss just jumped the gun on me and bought a cloudmin for physical systems license, I "think" that would not be br what we need, am I correct? Thanks, JohnM
So, just for my clarification, I should create a master and slave cloudmin so that it is not a single point of failure
You could setup a Master/Slave set of Cloudmin instances if you like, that does indeed provide additional redundancy.
Cloudmin calls those "replicas", their setup is described here:
http://www.virtualmin.com/documentation/cloudmin/repl
build my two Virtualmin servers using shared storage, and then round robin the virtualmins through cloudmin, Correct?
That question depends on how you wish to do the failover.
The simplest failover is the one using shared storage. If you have a SAN device, then Cloudmin can launch your VM's using another server if the server they're on fails.
But, that requires having such shared storage... not everyone has that, and it's not always cheap :-)
If you prefer round robin style failover -- that does not require shared storage, but it involves a more complex setup.
The round robin failover assumes that you have N servers setup, and that you have a way to keep all N servers in sync with each other. All Cloudmin does is test those N servers, and if one goes down, it removes it from the group.
As a follow up, I currently have a license for Virtualmin for 50 domains, my assumption is I will need to get a second similar license for the second virtualmin.
Only if it's serving requests.
If it's acting as a spare, and not actively serving requests, there's no need to buy a new license.
So if you go with the failover method that uses the shared storage, and not round robin, you wouldn't need an additional license.
With Cloudmin I am not sure if I will need to ten instance licenses to start or if one ten instance license will cover the master and the slave cloudmin?
That's a fine question! I'll have to ask how that works :-)
Certainly in the meantime, while you're setting things up, feel free to use your one license on both systems... but I'll get clarification on whether using a master/slave setup means you'd need another license.
The boss just jumped the gun on me and bought a cloudmin for physical systems license, I "think" that would not be br what we need, am I correct?
It might be able to do the Round Robin failover. You could see if that option is available in System Monitoring -> Roundrobin DNS Records.
It wouldn't work for the shared-storage style failover, since that requires using Xen guests. Cloudmin for Physical Systems can access Virtualmin on a Xen guest, but it can't manage the Xen instance itself (which is what you'd need for the shared-storage failover to function).
Does that all make sense?
-Eric
Okay, Jamie tells me that you do not need a second Cloudmin license for a replica/slave Cloudmin instance.
-Eric
Thank You for the quick follow up. I will start with what I have and see if i can manage the round robin fail over with the Cloudmin for physical servers. If that doesn't work I will push for the upgrade to the 10 instance license. JohnM