Online config LLT interface

[joagmv]

Recently I realized that a llt interface in a cluster is not working because the nodes are in different vlans (the interface uses broadcast conf):

Node 0:

NODE0:~ # cat /etc/llttab

set-node NODE0

set-cluster 1047

set-timer peerinact:3200

link eth2 eth-00:10:18:0b:7e:12 - ether - -

link eth3 eth-00:10:18:0b:7e:13 - ether - -

link-lowpri eth0 eth-00:14:5e:7b:08:1a - ether - -

NODE0:~ # ifconfig eth0

eth0      Link encap:Ethernet  HWaddr 00:14:5E:7B:08:1A  

          inet addr:10.92.5.134  Bcast:10.92.5.255  Mask:255.255.254.0

Node 1:

NODE1:~ # cat /etc/llttab

set-node NODE1

set-cluster 1047

set-timer peerinact:3200

link eth2 eth-00:0e:0c:ba:3e:ae - ether - -

link eth3 eth-00:0e:0c:ba:41:96  - ether - -

link-lowpri eth0 eth-00:14:5e:7a:aa:3c - ether - -

NODE1:~ # ifconfig eth0

eth0      Link encap:Ethernet  HWaddr 00:14:5E:7A:AA:3C  

          inet addr:10.93.146.123  Bcast:10.93.147.255  Mask:255.255.254.0

I think I should configure eth0 as an UDP interface, shouldn't I?? I tried somethink like that and It seemed to work:

Node 0:

//Specifying the other node IP as the broadcast address

lltconfig -t eth0 -d eth0 -b udp -I 10.92.5.134 -B 10.93.146.124

Node 1:

//Specifying the other node IP as the broadcast address

lltconfig -t eth0 -d eth0 -b udp -I 10.93.146.123 -B 10.92.5.134

Is this correct?? What should I define in the llttab file??

Regards,

joagmv

[mikebounds · Accepted solution]

There is a sample llttab file for LLT over UDP at https://www-secure.symantec.com/connect/forums/if-llt-could-be-configured-over-udp-nat#comment-75424....

Note also, you can't mix LLT over UDP and LLT over Ethernet - see https://www-secure.symantec.com/connect/forums/how-configure-llt-over-udp-when-you-have-more-1-node-...

So your config will look something like:

set-node NODE0

set-cluster 1047

link hb-eth2-nat /dev/udp - udp 50100 - IP-on-eth2-on-node0 -

link hb-eth3-nat /dev/udp - udp 50101 - IP-on-eth3-on-node0 -

link-lowpri hb-eth0 /dev/udp - udp 50102 - 10.92.5.134 -

set-addr 1  hb-eth2 IP-on-eth2-on-node1

set-addr 1  hb-eth2 IP-on-eth3-on-node1
set-addr 1  hb-eth0 10.93.146.123

#disable LLT broadcasts

set-bcasthb 0

set-arp 0

I have just chosen 3 UDP ports at random - 50100, 50101, 50102.

Mike

[joagmv]

Very helpful Mike.

So, are the commands I executed correct?? I mean, does the command "lltconfig -l -t eth0 -d eth0 -b udp -I 10.92.5.134 -B 10.93.146.124" translate to

link-lowpri hb-eth0 /dev/udp - udp 50102 - 10.92.5.134 -

set-addr 1  hb-eth0 10.93.146.123

???

The main doubt I have is about the -B param...

[mikebounds]

The VCS install guide says:

Use LLT over UDP in the following situations:
 

■ LLT must be used over WANs

■ When hardware, such as blade servers, do not support LLT over Ethernet
 

LLT over UDP is slower than LLT over Ethernet. Use LLT over UDP only when the

hardware configuration makes it necessary.

And also says:

The set-addr command in the /etc/llttab file is required when the broadcast

feature of LLT is disabled, such as when LLT must cross IP routers.

So my understanding is that if you have hardware, such as blade servers, that does not support LLT over Ethernet, then you use Broadcast feature, otherwise, for WANs when LLT must cross IP routers you disable broadcast and use specific IPs.

So the "-B" is for broadcast address, but you have not set a broadcast address, so I am surprised your command resulting in a working config.    The broadcast address is the last arg in the llttab, so an example of lines in the llttab when using broadcast feature is:

link link1 /dev/udp - udp 50000 - 192.168.30.1 192.168.30.255

link link2 /dev/udp - udp 50001 - 192.168.31.1 192.168.31.255

So if you actually put in your broadcast so ran:

lltconfig -l -t eth0 -d eth0 -b udp -I 10.92.5.134 -B 10.92.5.255

then I suspect it won't work as broacast won't cross routers and by using an IP in place of broadcast address, probably means your config is not supported.

Mike

[joagmv]

If i define the -B as the actual broadcast address, It doest work:

NODE0:~ # ifconfig eth0

eth0      Link encap:Ethernet  HWaddr 00:14:5E:7B:08:1A  

          inet addr:10.92.5.134  Bcast:10.92.5.255  Mask:255.255.254.0

NODE1:~ # ifconfig eth0

eth0      Link encap:Ethernet  HWaddr 00:14:5E:7A:AA:3C  

          inet addr:10.93.146.123  Bcast:10.93.147.255  Mask:255.255.254.0

NODE0:/etc # lltconfig -t eth0 -d eth0 -b udp -I 10.92.5.134 -B 10.92.5.255

NODE1:/etc # lltconfig -t eth0 -d eth0 -b udp -I 10.93.146.123 -B 10.93.147.255

NODE0:/etc # lltstat -nvv | head

LLT node information:

    Node                 State    Link  Status  Address

   * 0 NODE0         OPEN    

                                  eth2   UP      00:10:18:0B:7E:12

                                  eth3   UP      00:10:18:0B:7E:13

                                  eth0   UP      10.92.5.134

     1 NODE1         OPEN    

                                  eth2   UP      00:0E:0C:BA:3E:AE

                                  eth3   UP      00:0E:0C:BA:41:96

                                  eth0   DOWN    

NODE1:/etc # lltstat -nvv | head

LLT node information:

    Node                 State    Link  Status  Address

     0 NODE0         OPEN    

                                  eth2   UP      00:10:18:0B:7E:12

                                  eth3   UP      00:10:18:0B:7E:13

                                  eth0   DOWN    

   * 1 NODE1         OPEN    

                                  eth2   UP      00:0E:0C:BA:3E:AE

                                  eth3   UP      00:0E:0C:BA:41:96

                                  eth0   UP      10.93.146.123

BUT, if I define the broadcast as the other IP, it works:

NODE0:/etc # lltconfig -u eth0

NODE0:/etc # lltconfig -t eth0 -d eth0 -b udp -I 10.92.5.134 -B 10.93.146.123

NODE1:~ # lltconfig -u eth0

NODE1:~ # lltconfig -l -t eth0 -d eth0 -b udp -I 10.93.146.123 -B 10.92.5.134

NODE0:~ # lltstat -nvv | head

LLT node information:

    Node                 State    Link  Status  Address

   * 0 NODE0         OPEN    

                                  eth2   UP      00:10:18:0B:7E:12

                                  eth3   UP      00:10:18:0B:7E:13

                                  eth0   UP      10.92.5.134

     1 NODE1         OPEN    

                                  eth2   UP      00:0E:0C:BA:3E:AE

                                  eth3   UP      00:0E:0C:BA:41:96

                                  eth0   UP      10.93.146.123

So... my doubt is about taking off the low-priority interface (we do not eant to pass the others LLT interfaces to UDP or just leaving the config that (mixing llt and udp with the broadcast trick...

Regards,

Joaquín