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Discussion: Can we bind multiple domains to the same bridges?
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 chandu.komali |
Can we bind multiple domains to the same bridges?
Mar 28 2008, 2:17 AM EDT Have question here. Say, eth0 is bound to xenbr0, eth1 is to xenbr1 and eth2 is to xenbr2. Can I create multiple domains where each domain accessing to all the bridges? For eg, xen1 points to eth0, xen1-vlan1 points to eth1 xen1-vlan2 points to xenbr2 with three different IP addresses. Now, can I create xen2 on the same VM server by using all the eth cards binding to xen2, xen2-vlan1 and xen2-vlan2 all pointing to a different set of IP addresses? In short, my VM has got three Ethernet cards. I would like to create 5-6 domains all use the same Ethernet cards. Is this possible? 0 out of 1 found this valuable. Do you? |
 martin_foster |
RE: Can we bind multiple domains to the same bridges?
Apr 10 2008, 1:33 AM EDT In short, yes. Note that there are (were?) limits in the xen code which prohibited having more than 3 network interfaces per virtual machine. This generally isn't an issue if you're using trunks to access multiple vlans. You can disable the use of the xenbr## named devices, and xen's interference with networking altogether. From a design and maintenance perspective, having two scripts (the OS's and xend's) vying to alter the system's networking can lead to configuration collisions and unexpected behaviour. The xen scripts should simply connect virtual interfaces to per-vlan bridges, or trunked interfaces on the host and leave the generation of these bridges/interconnects/etc to the OS's networking scripts. for details, see: http://wiki.oracle.com/page/Oracle+VM+Server+Configuration-+bonded+and+trunked+network+interfaces Note that VM manager 2.1.0 & 2.1.1 won't see bridges that aren't named xenbr##. This limitation is quite arbitary and due to the OVS agent code on the dom0 systems. It can be removed by editing /opt/ovs-agent-2.2/OVSXXenStore.py: [root@virtual5 ovs-agent-2.2]# diff -Naru OVSXXenStore.py-ORIG OVSXXenStore.py --- OVSXXenStore.py-ORIG 2008-04-10 23:45:18.000000000 +1000 +++ OVSXXenStore.py 2008-04-10 23:44:10.000000000 +1000 @@ -339,7 +339,7 @@ is_mgmnt_if = True if netdev in d: vif_num = re.search("[0-9]+", netdev).group() #0 - bridge = "xenbr%s" % vif_num #xenbr0 + bridge = "%s" % vif_num #xenbr## restriction REMOVED if bridge in d: if is_mgmnt_if: bm.insert(0, "%s=%s" % (bridge, d[netdev])) 0 out of 1 found this valuable. Do you? |
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fontec938 fontec938 |
RE: Can we bind multiple domains to the same bridges?
May 16 2008, 10:43 AM EDT I have a quick example where this is not working correctly. To start I have disabled the network-bridges script from /etc/xen/xend-config.sxp file. I followed the instructions in another forum. I basically replaced the line (network-script network-bridges) with (network-script network-dummy). This allows me to create my own bridge below. I have two devices eth0 and eth1. I assign 0.0.0.0 to the two devices and then bridge them to joesb. I assign a public ip address to joesb and then bring up eth0 and eth1. I am then able to ping a server (192.168.0.1) that has ovm installed and I get a response back. Below is the following commands I use to accomplish this. brctl addbr joesb ifconfig eth0 0.0.0.0 ifconfig eth1 0.0.0.0 brctl addif joesb eth0 brctl addif joesb eth1 ifconfig joesb 192.168.0.100 netmask 255.255.255.0 up ifconfig eth0 up ifconfig eth1 up ping 192.168.0.1 I then edit the /opt/ovs-agent*/OVSXXenStore.py the way you have specified it above. After rebooting or stopping the ovs-agent and restarting it I am still unable to see the bridge joesb in the drop down list. A few questions: Where and when do the functions xen_get_network_bridges and xen_get_network_bridges2 get called? Why do you not use the system command brctl show to identify what bridges have been created on the system? Is it necessary to have a peth device because it seems there are numerous if statements in the python code that search for a device that starts with the letter p? I have heard that the python code in the agent will change to allow system administrators to create their own network scripts and devices. This will allow us to name our bridges anything we want. Is this code complete yet for the new release? If so can we pilot it? Do you find this valuable? |