Re: [Xen-API] xcp-xapi bonding

[Alexandre Kouznetsov <alk@xxxxxxxxxx>]

Hi.

El 11/03/13 23:27, Carlos Reategui escribió:
>         eg:
>
>         auto eth0
>         iface eth0 inet manual
>
>         auto eth1
>         iface eth1 inet manual
>
>         Do I also need to set up the bridge in this file or will that be
>         done
>         automatically by xcp-xapi. Eg:
>
>         auto xenbr0
>         iface xenbr0 inet dhcp
>         bridge_ports eth0
>
>         auto xenbr1
>         iface xenbr1 inet dhcp
>         bridge_ports eth1
>
>     As a reference, very unrelated to Xen-API or XCP, please note that
>     this would not create any "bond", but a plain "bridge". The bonding
>     magic is done by vSwitch in XCP (and probably XenAPI). Other
>     observation is, that Debian based distribution does not need to have
>     eth0 or eth1 interface described or set up, in order to make a valid
>     bridge via /etc/network/interfaces file.
>
> Understood, but do I need to define a bridge to both eth0 and 1 in the
> interfaces file in order to bond them.  Hmm as I type that  it does not
> sound right.  If I am going to bond eth0 and 1, do I need to even bother
> setting up bridges for them?
I you use Debian's means (Ubuntu's, whatever), you would make a "bond" 
of them, then make a "bridge" and declare the bond as part of it.
If, instead, you use xe-toolstack means, it will create a bridge with 
the involved physical interfaces and use vSwitch backend to make it 
behave as bond (I have not done my homework on vSwitch yet).
>  Seems like a bridge is a "network" in xapi
> which is what I'll be creating in xe.
A "network" references a associated bridge, but they are not objects of 
the same order. Using xe-toolstack, you will normally not be referencing 
the bridges directly.
Example:
[root@xcp-node24 ~]# xe network-list name-label=DMZ
uuid ( RO)                : 35f46450-037a-1c42-d6c7-e310f19f278d
          name-label ( RW): DMZ
    name-description ( RW): Exposed network
              bridge ( RO): xapi1


>     Look at this example:
>     auto xenbr01
>     iface xenbr01 inet manual
>        bridge_ports eth1
>        bridge_stp off
>        bridge_maxwait 0
>        bridge_fd 5
>
>     This creates a bridge, set it up automatically on boot, without need
>     to declare anything about eth1 itself. After configured, ifconfig
>     shows eth1 in UP state, but there is no need for any "auto eth1" or
>     "iface eth1" lines.
>
> I guess the assumption here is that xapi picks this up when it is first
> setup, or do you add "xenbr01" as a network using xe yourself.
No, that was a example of a regular Xen configuration on Debian, without 
xapi, sorry for lack of clearance.
My only available xapi runs XCP, which is CentOS, so there is no 
/etc/network/interfaces there, and the syntax is completely different. 
the contents of /etc/sysconfig/network-scripts/ suggests there is no 
OS-level configuration for eth*, everything seems to be done by 
xe-toolstack. But, can't say for sure, not too familiar with CentOS.

>         Using xe I am guessing I would then do the following:
>
>         ETH0=`xe pif-list device=eth0 --minimal`
>         ETH1=`xe pif-list device=eth1 --minimal`
>         NETID=`xe network-create name-label=bond0`
>         BONDID=`xe bond-create network-uuid=$NETID pif-uuids=$ETH0,$ETH1`
>
>
>     Note that if your host is a part of a cluster, "xe pif-list
>     device=eth0" will return a list of PIF's instead of a single one.
>
>
>     The commands you listed should work, but they will bond your first
>     two interfaces together. Your administration interface could behave
>     funny.
>
> By administration did you mean management?  I want this bond to be my
> management and guest traffic interface.
Yes, management.

>           Would it be better to
>         not use dhcp in the interfaces file?
>
>     Yes, much better. On any server. Except, maybe, very special cases.
>
> I'm just going to use it for initial setup where it gets from a
> temporary ip pool. Then switch to static when configuring via xe.
On XCP, he change from DHCP to static (my PXE install leaves the network 
in DHCP mode) is pretty painless. In case of xapi on Ubuntu, I'm not 
sure how well would it handle the change. I would reduce variables and 
set it to static before installing xapi.
>         For my NFS network using a bond of eth2 and 3 I was thinking of
>         keeping
>         them from xcp and just telling it to "xe pif-forget" on the
>         uuids for
>         those.  Is that ok?  Im assuming as long as the host knows about
>         that
>         network it should be fine.
>
>     Making this network not to be attached to the new VM's would be enough:
>     NEWNET=`xe network-list name-label="PUT YOURS HERE" --minimal`
>     xe network-param-set uuid=${NEWNET} other-config:automatic=false
>
>     If you do pif-forget, most likely xapi will be unable to manage a
>     bond using this interface. Unless you intend to manage this
>     interfaces completely out of the scope of xapi.
>
> Yes.  That was the plan.  I was going to create an LACP bond in the
> interfaces file for my storage network since my storage switch does
> support LACP.
Since your VM's will not use this interface, you don't need to make a 
bridge of it:
iface bond1 inet static
  address XX.XX.XX.XX
  netmask YY.YY.YY.YY
  slaves eth2 eth3
  bond_miimon 100
  bond_updelay 100
  bond_downdelay 200
  bond_mode 802.3ad


Greetings.


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