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Oracle 12c RAC Instalation on OL 6.5 host

Questions relating to Oracle Real Application Clusters (RAC) and Clusterware.

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pb2070
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Oracle 12c RAC Instalation on OL 6.5 host

Postby pb2070 » Mon Apr 21, 2014 2:58 pm

Hi Tim.

I followed your detailed and clear explanation from this article "
http://www.oracle-base.com/articles/12c ... ualbox.php
"
My question is about nslookup. When i typed " nslookup <scan-host> " it is not giving the out put with the 3 SCAN IPs .

Before i put my question i would like to be specfic with System configuration details.

-- At job we have remote OL 6.5 test server from "xyz" company with root access. Memory and everything is fine and good.
We have access as "root" only for this machine but If any changes are required then we have to raise a ticket.
- Networking for this machine is done by the company. The IP is assigned as 85.2x.2x.xxx

-- I installed " Oracle Virtual Box for Linux 64 bit '" on this OL Host. Installed 2 OL 6.5 (Guest) Systems or Virtual Boxes for 12c RAC Installation.
So, on OL 6.5 we have again 2 OL 6.5 Systems. Did yum update for the both Virtual Boxes

-- "dnsmasq " service is started on the both Virtual boxes. Firewall is deactivated.

-- The "/etc/hosts " file for both Virtual Boxes has all the IPs exactly you mentioned in your article.
But, the loopback IP is in this way on both virtual boxes

127.0.0.1 localhost.localdomain localhost localhost4.localdomain localhost4

-- the "/etc/resolv.conf" file on both virtual boxes is exactly the same as in your article.

My question is
Do I need to do any changes in dnsmasq configuration file in order to get SCAN IPs working?
What could be the possible reason for " nslookup <scan host> " not to work and not to display the 3 SCAN IPs ?
When i checked ""
Is it any problem if i also add " server 127.0.0.1 " in the /etc/resolv.conf file of both virtual boxes ?


Thanking you,
pb

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Re: Oracle 12c RAC Instalation on OL 6.5 host

Postby Tim... » Mon Apr 21, 2014 5:02 pm

Hi.

Your SCAN is not going to work with Dnsmasq running on each node. It should be configured on the host machine, not on the VMs. The article says,

"The DNS can be configured on the host machine using BIND or Dnsmasq, which is much simpler. If you are using Dnsmasq, put the RAC-specific entries in the hosts machines "/etc/host" file, with the SCAN entries uncommented, and restart Dnsmasq."


By running Dnsmasq locally on the RAC nodes, they are just ignoring it and using the "/etc/hosts" file to resolve the names. As a result, the SCAN will only ever resolve to a single IP address.

When you use Dnsmasq on the host, the VMs look to the host for name resolution, so Dnsmasq can do it's job!

Cheers

Tim...
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Re: Oracle 12c RAC Instalation on OL 6.5 host

Postby pb2070 » Tue Apr 22, 2014 12:51 pm

Hi Tim.

Thank you for correcting my mistake !
It is very bad that I missed out the important information :(

Even now I am not getting the 3 SCAN IPs when I type nslookup ora-rac1-scan on RAC Nodes

I performed the below on host machine:
-- saved all the RAC specific IPs in /etc/hosts file
-- started dnsmasq service and also stop and restart too
-- uncommented the 3 SCAN IPs

After this I logged in to RAC Node and typed nslookup ora-rac1-scan and the output was not 3 IPs :(

Just to check the output and confirm vboxnet0 (Virtual box network adapter) is working or not I typed " route" on host machine and the
output was "192.168.56.0". The vboxnet0 Virtual box network adapter is working.

The hosts file on the host machine is
*********************
127.0.0.1 localhost localhost.localdomain localhost4 localhost4.localdomain

82.x.x.x <host> <host>.xyz.com
64.x.x.x <host> <host>.xyz.com

# Public
192.168.56.101 ora-rac1.localdomain ora-rac1
192.168.56.102 ora-rac2.localdomain ora-rac2
# private
192.168.1.101 ora-rac1-priv.localdomain ora-rac1-priv
192.168.1.102 ora-rac2-priv.localdomain ora-rac2-priv
# Virtual
192.168.56.103 ora-rac1-vip.localdomain ora-rac1-vip
192.168.56.104 ora-rac2-vip.localdomain ora-rac2-vip
# SCAN
192.168.56.105 ora-rac1-scan.localdomain ora-rac1-scan
192.168.56.106 ora-rac1-scan.localdomain ora-rac1-scan
192.168.56.107 ora-rac1-scan.localdomain ora-rac1-scan
************
and /etc/resolv.conf on host is
# Generated by NetworkManager
search xyz.com
search localdomain
nameserver 82.x.x.x
nameserver 82.x.x.x
nameserver 192.168.56.1


and /etc/resolv.conf of RAC Node 1 and Node is with

search localdomain
nameserver 192.168.56.1

and /etc/hosts files of RAC Nodes are with SCAN IPs commented

When I ping " ora-rac2 " and "ora-rac2-priv" the machines are communicating with 0% packet loss.

:( Do not know where the problem exists?

Thanking you,
pb

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Re: Oracle 12c RAC Instalation on OL 6.5 host

Postby Tim... » Tue Apr 22, 2014 1:08 pm

Hi.

You said you restarted the Dnsmasq service, then uncommented the the scan from the hosts file. That is the wrong way round. You need to restart Dnsmasq on the host whenever you make changes to the hosts "/etc/host" or "/etc/resolv.conf" files.

Cheers

Tim...
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pb2070
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Re: Oracle 12c RAC Instalation on OL 6.5 host

Postby pb2070 » Tue Apr 22, 2014 2:42 pm

Hi.
Firstly I saved IPs in /etc/hosts file and then started dnsmasq.
When I did not get the expected output with nslookup I restarted.

Everything is fine - network adapter, ping between RAC Nodes.
But, Do not know why it's still not working.

I raised a ticket with xyz company by whom we have Remote Test Server.
They replied, "I think you should configure Bridge Adapter " :) I Informed them it is about RAC Installation, 3 IPs and SCAN etc.
And they pinged to one of the virtual box. They have got "host is unreachable"

I presume there is some network configuration problem by this company.

Cheers
pb

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Re: Oracle 12c RAC Instalation on OL 6.5 host

Postby Tim... » Tue Apr 22, 2014 7:35 pm

OK.
Tim...
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Re: Oracle 12c RAC Instalation on OL 6.5 host

Postby pb2070 » Tue Apr 22, 2014 7:37 pm

Hi Tim :)

Kept my mind cool for couple of seconds and restarted the host machine!
Boom, boom!! on both of the RAC Nodes it displayed the 3 SCAN IPs when i ran nslookup <SCAN HOST>

Cheers,
:)
pb

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Re: Oracle 12c RAC Instalation on OL 6.5 host

Postby Tim... » Tue Apr 22, 2014 7:40 pm

:)
Tim...
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pb2070
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Re: Oracle 12c RAC Instalation on OL 6.5 host

Postby pb2070 » Wed Apr 23, 2014 1:42 pm

Hi Tim.

Another unknown error come up and this is totally unknown service to me.
When I ran " runcluvfy stage ... -verbose " as oracle user It says
"pre check for cluster services is unsuccessful on all nodes" and reason is
that "avahi-daemon" not configured and not running.

On the Linux Host I checked "service avahi-daemon status" and the output is unknown service.
Then I found in the /etc this file "avahi-autoipd.action"

I understand this service should be running on Host, right?
Could you advise me .

Cheers,
pb

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Re: Oracle 12c RAC Instalation on OL 6.5 host

Postby pb2070 » Wed Apr 23, 2014 2:07 pm

Hi.
I think it is my mistake not to configure ssh keys as oracle user.
That's done as root user.
I will do it and recheck

Sorry & cheers,
pb

pb2070
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Re: Oracle 12c RAC Instalation on OL 6.5 host

Postby pb2070 » Thu Apr 24, 2014 8:18 pm

Hi Tim :)
It was good experience to install RAC because of your brief explanation! Thank you very much!
( I actually did this for myself and also for my colleagues who do not understand English much as they are basically native German speakers and did not have time to try.
It is intersting for them now!)

I have some questions. I would be glad to hear from you if you could and have time.

To experience the errors with RAC I clicked on "next" even though I saw "cluster syncronization services failed" during Cluster Install.
And, created Database. When RAC was started Instance on RAC2 was not reachable.

I expected it because i saw the system times were automatically with a difference of 2 minutes :(

I did this steps.
Step 1:
Adjusted both of the RAC systems' time navigating " Adminstration -> Date and Time ".
But, I do not understand one thing. Although the time zone was set during Server install how come the virtual boxes change the system clock?

In MOS Community i read posts about this topic and i understood that NTP is the right thing to depend on but not on "CSSD daemon"
It is indeed a system service so it is the right way. Could you please conform ?

Step 2
I performed the below steps on RAC nodes step-by-step and the instances started normally :)
I would have to bother you to let me is this the right approach?

- # crsctl stop/start crs
- # crsctl stop/start res -init -all
- # crsctl stop/start has

When both the instances started i see again time difference. But they were up and running.
Surprise, surprise!

Cheers and thanking you,
pb

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Re: Oracle 12c RAC Instalation on OL 6.5 host

Postby Tim... » Thu Apr 24, 2014 9:03 pm

Hi.

1) NTP is considered mandatory for most real servers. For virtual servers this is really important. Time slippage of virtual servers has been well documented over the last decade+. :)

2) If your aim is to restart everything, I would suggest the following:

# /etc/init.d/init.ohasd stop
# /etc/init.d/init.ohasd start

This is the service that is used when you shutdown/startup the system...

3) It is probably worth turning off everything, resetting the time, the turning everything on. The Oracle process may be screwing stuff up if you change the time while the processes are running...

Cheers

Tim...
Tim...
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pb2070
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Re: Oracle 12c RAC Instalation on OL 6.5 host

Postby pb2070 » Tue Apr 29, 2014 8:09 am

Hi Tim :)

It was successful installation !
Yes, I did shutdown everything and performed the steps you mentioned. Very helpful !
Thank you very much !!! Without your guidance things would not have been simple.
And, needed to patch Database Express 12c to keep it working.

Also, I did try the below commands and following your 12c Articles...

# ./crsctl check cluster -all
To stop Oracle Clusterware and Oracle ASM instances on all nodes in the cluster:
# ./crsctl stop cluster -all
# ./crsctl start cluster -all
$./srvctl status listener
$./srvctl status asm
$./srvctl status database -d <rac db name>
$./srvctl status nodeapps

Cheers,
pb

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Re: Oracle 12c RAC Instalation on OL 6.5 host

Postby Tim... » Tue Apr 29, 2014 8:28 am

:)
Tim...
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