Xenserver 5.5 network setup 1

[pinkpanther56]

Hi all, can I post Citrix Xenserver questions here?


I’m reading conflicting information on the network setup for Xenserver. I have two servers with 4 network cards i'd like to have on each server, 2 bonded cards to carry VM storage traffic (iSCSI) and 2 bonded cards to carry general network traffic and the management interface. The problem is that i've seen this below in the xencenter docs.

Note that a server with its management interface on a bond will not be permitted to join a pool. You will need to reconfigure the server's management interface and move it back on to a physical NIC before it can join a pool.

but i've also seen this as well...

Citrix recommends configuring management networks using a dedicated network interface or interfaces configured in a bond. The interface may be shared with VMs if desired; however, Citrix recommends separating VM, management, and storage traffic.

So the question is if I configure a xenserver to have 2 cards for storage and another bond with 2 cards for general LAN traffic and the management interface will this cause issues when I add a second xenserver to the pool as indicated in the first quote?

Anyone got a setup like this.

Cheers.

 

[engjohn]

No, what you do is create the resource pool first.
Then add your servers. Then create the Network bonds on the primary server and all other servers will automatically create the bonds to match the primary server (Pool Master).
The pool master is the first server listed at the top.

 

[pinkpanther56]

I'll give this a try when I'm back at the box. So are you saying that I can create a pool first before adding any servers then the first added server becomes the master?

Can you also tell me the best way to bond NIC's if I create a bond in Xenserver do I need to add those ports to a LACP trunk on the switch as well or should no additional settings be required on the switch?

Thanks.

 

[pinkpanther56]

Ok I seem to of created two bonds now one includes cards 0+1 and the other 2+3. I've added both servers to the pool and they seem to be configured ok. I then added my iSCSI connection to the SAN and have a VM running on it.

The question is how do I tell which bond the iSCSI is connected on?

Thanks.

 

[engjohn]

You want to have physically separate networks for storage and management on different subnets.
Right click on your servers ad select Management Interfaces.
From there you can assign IP address to the different bonds.
Also, make sure that your storage Bond is not setup to be added to the VMs by default. Right click on you bond and select properties, under network settings make sure the check box is not checked to add to VMs automatically.

 

[pinkpanther56]

I couldn't seem to find a way to add IP addresses to bonds, i've got two bonds configured but can't see how to add an IP. I'm not at a server now to look but I remember if I just bonded the NICs that option didn't seem to be there I had to create an external network connection to add an IP.

What is the correct way to do this?

Does the iSCSI traffic have to be a seperate IP subnet or will VLAN seperation do?

Thanks for your help.

 

[engjohn]

In the xencenter, right click on your server, select management interfaces, and you can manage the ipaddress of the bonded interfaces there.

Vlan separation may work, you just need to make sure that there is NO WAY to route traffic between the VLANs to ensure that the proper interfaces are used for storage and for management.

I much Prefer to have my storage network on physically separate equipment on its own battery backup. You really do not want to loose power on your storage network!

 

[pinkpanther56]

Vlan separation may work, you just need to make sure that there is NO WAY to route traffic between the VLANs to ensure that the proper interfaces are used for storage and for management.

Ok so the only real way to make sure Xen is using the correct bond for storage is to seperate them onto a different subnet/network.

Cheers.

 

[pinkpanther56]

Will this create a problem if I wanted to present an iSCSI LUN to one of the VM's. One of the VM's might be a file server and the data will reside on the SAN. In the setup desribed above the virtual OS wouldn't be able to see the SAN directly right?

 

[engjohn]

Correct.

 

[pinkpanther56]

Can I just change the Xen settings to add the NICs that are on the private IP range to the virtual OS to allow it to map an iSCSI LUN then?

Thanks.

 

[engjohn]

You could add the iSCSI NICs as a second NIC to the VM. I would not have a gateway or anything on that NIC. You do not want any unnecessary traffic on that network.

 

[pinkpanther56]

I've discovered that I can create virtual disks on the SAN in Xen and then present them to a Windows VM to use as a D: drive and Windows just thinks it is an attached HD.