virtual hosts

[Giuseppe Centioli]

Good morning.
We have a 2 nodes Tru64 cluster and we would configure three virtual hosts, one for the cluster and one for each node.
We added three entries to the DNS and /etc/hosts containing the new IPs and hostnames.

From my client:
>ping gesau004v

Pinging gesau004v.it.mobile.marconi.com [10.31.239.244] with 32 bytes of data:

Request timed out.
Request timed out.

>telnet gesau004v
Connecting To gesau004v...Could not open a connection to host on port 23 : Connect failed

Why did pinging and telnet fail?
I have not registered the virtual hostnames with cluamgr.
Could this be the problem? If yes, should I use this command just for
the cluster virtual hostname, or for all virtual hostnames?

Thanks.
Giuseppe

[Vladimir Fabecic]

Hello
What do you mean "We added three entries to the DNS and /etc/hosts containing the new IPs and hostnames."?
DNS and /etc/hosts entries are just for address resolving.
In your case you MUST create those IP aliases using cluamgr.
I can give you instructions if neded.

[Al Licause]

Please explain the steps you used on the cluster members to create the aliases. You're on the right track by assuming that you probably didn't complete all of the steps necessary to fully register and configure the cluster aliases.

Normally this would involve two cluamgr commands. The first to declare the alias and the second to restart routing services which make the aliases available to anyone outside of the cluster:

cluamgr -a alias={alias_name},join
cluamgr -r restart

Don't forget to add the first command to /etc/clu_alias.config if you want these aliases to start on reboot. Or both commands to a caa script if they will be started on demand.

[Ivan Ferreira]

You must use cluamgr to create new cluster aliases (or virtual hosts for you).

Add the entry for the new alias en /etc/hosts:

On each member run:

/usr/sbin/cluamgr -a alias=hostname.example.com,rpri=2,selw=3,selp=1,join,virtual=f


Add the lines in /etc/clu_alias.config

See the cluamgr man page for a description of the parameters.

[Giuseppe Centioli]

Hi guys.
I am a little bit confused about the commands I should execute

Here is what I have:

Cluster virtual hostname=gesau003v
(it should redirect to node1 or node2 with the same probability);
node1 virtual hostname=gesau004v;
node2 virtual hostname=gesau005v.

What are the exact commands and should I execute the same commands on each node?

Thanks a lot.
Giuseppe

[Ivan Ferreira · Accepted solution]

On node1 run:

/usr/sbin/cluamgr -a alias=clugesau003v,rpri=2,selw=3,selp=1,join,virtual=f

On node2 run:

/usr/sbin/cluamgr -a alias=clugesau003v,rpri=1,selw=3,selp=1,join,virtual=f

The priority are the same (selp) and you will get 3 connections to one server (selw) then will go to the other server. Node1 will manage the routing for the aliase (rpri)

[Vladimir Fabecic]

Default cluster alias is just an IP alias taken by node that was booted first. In most cases it is useless.
If you want that alias redirects to node1 or node2 with the same probability, you should use DNS round-robin (which is prefered method for me) or metric+loadbroker.
These limitations are caused by limitations of IP protocol itself.
What will this cluster be used for (Oracle RAC, web server ...)?

[Giuseppe Centioli]

The cluster will be used as an Oracle RAC DB server.

Ivan, why don't I have to execute:

/usr/sbin/cluamgr -a gesau004v ...
/usr/sbin/cluamgr -a gesau005v ... ?

How does the network know that gesau004v is node1?

Thanks.
Giuseppe

[Ivan Ferreira]

The syste knows the node because you are executing the command on that node, and the alias=clugesau003v is the virtual host that you want to create/join.

For example:

node1 192.168.1.1
node2 192.168.1.2

Alias 192.168.1.3

When you run on node1, you are telling that you want to join to alias 192.168.1.3.

[Giuseppe Centioli]

Sure.
But the hostname for node1 is not gesau004v:
it is gesau004.
..and hostname for node2 is not gesau005v:
it is gesau005.

gesau004 and gesau004v have different IP.
gesau005 and gesau005v have different IP.

Do you understand what I mean?
Bye Ivan.
Giuseppe

[Johan Brusche]

On gesau004

ifconfig eeN alias ip-of-gesau004v netmask xxx.yyy.z00

On gesau003

ifconfig eeN alias ip-of-gesau003v netmask xxx.yyy.z00

Put above commands in /etc/inet.local for reuse at next reboot.

Rgds,

____ Johan./

[Ivan Ferreira]

If what you want is to have two IP's on the same machine use Johan's recommendation.

If you want to have 1 IP for the two machines and balance the load, use cluamgr.

[Giuseppe Centioli]

Thanks a lot.
Have a nice day.

Giuseppe

[Giuseppe Centioli]

Hi.
I ran cluamgr for each virtual host and fixed the problem.

Bye.
Giuseppe