Best option for a cluster on a dedicated server

[Diogo Jesus]

Hello, currently we have 2 servers hosted in SoYouStart, only problem is that they're not in a cluster and if one server fails then the services running inside go down.

For this matter we've been studying the best option to create a proxmox cluster.

So far we have 2 options, the first one (and cheapest), is to keep our servers at SoYouStart, buy a 3rd server and a cloud vps somewhere to host a VPN server. Then connect all these 3 servers to the VPN and create a cluster.
This option problem is that each server only has 250mbps upload/download, and I wonder how much I would need to keep the servers connected to the vpn and also provide fast connection to our applications.

Our second option is to use OVH with their vRack option which basicly is the same as the first one but their VPN is internal which allows me to connect each server to a 1gbps local network and 1gbps extra for external network (per server).

Obviously the 2nd option sounds better but is it really necessary? How much internet speed do we really need to connect all three servers between them?

Thank you

 

[aaron]

Besides bandwidth considerations you really need to take latency into account if you want to set up a cluster.
Corosync needs low latency (<5ms) to work properly.

What do you plan regarding HA? You will either need a shared storage or storage replication to be able to start a VM on another node if one goes down.

 

[Diogo Jesus]

Besides bandwidth considerations you really need to take latency into account if you want to set up a cluster.
Corosync needs low latency (<5ms) to work properly.

I see, if using vRack provided by OVH i'm the sure latency will be really small because it uses the same OVH network behind.

What do you plan regarding HA? You will either need a shared storage or storage replication to be able to start a VM on another node if one goes down.

Didn't thought about this yet, I thought that I could replicate the containers/VMs storage between different nodes without having a storage dedicated server. If that's the case then I need to see other options containing a server for dedicated storage

 

[aaron]

I see, if using vRack provided by OVH i'm the sure latency will be really small because it uses the same OVH network behind.

I don't have any experience with that so I cannot say if it will work or not.

I thought that I could replicate the containers/VMs storage between different nodes without having a storage dedicated server.

If you use ZFS as storage you can run replication between the nodes. In case of a failure on the source node you will lose data according to the intervals you set the replication to.

 

[Diogo Jesus]

If you use ZFS as storage you can run replication between the nodes. In case of a failure on the source node you will lose data according to the intervals you set the replication to.

yes right now we have 2 servers under ZFS but they're not connected between them. The idea was having a 3rd server in "standby" which would turn on the different containers / VMs in case of a server failure on the nodes 1 or 2

 

[Diogo Jesus]

sorry for double posting but couldn't find this info anywhere online.
Is there an option to don't change the network settings of containers when they move from one host to another? For example we have an IP range alocated to our server1 and another IP range to our server2, since we're running mail server inside proxmox if server1 fails and the VMs/CTs are moved to server2, they will assign the same public IPs from server1 and that won't work, so basicly I need to setup new IPs for each VM/CT and work on a loadbalance behind it

 

[aaron]

Is there an option to don't change the network settings of containers when they move from one host to another?

Check if your hosting provider offers floating or failover IPs.

 

[Diogo Jesus]

Check if your hosting provider offers floating or failover IPs.

They do provide failover IPs but under 1 server, for example if a failover IP 1.2.3.4 is signed to server1, I need to manually transfer it to server2 to make it usable, this could be reached by API (need some reading) but it still takes some minutes for it to take effect, so it's not the most viable option.


Another option that I was thinking was to assign my IPs to the OVH vRack, I guess that's an option but I would need some testing to it. Basicly vRack allows me to connect different servers to the same internal network, and if I assign my IPs to the vRack then maybe I could use them on my both servers. Just need to test it to see if the servers recognize the IPs