Setting up CTDB on OCFS2 and VMs ...

[ronnie sahlberg]

On Tue, Dec 16, 2014 at 9:38 AM, Stefan Kania <stefan at kania-online.de> wrote:
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> Hi Rowland,
>
>
> Am 16.12.14 um 15:27 schrieb Rowland Penny:
>> On 16/12/14 13:12, Stefan Kania wrote: Hi Rowland,
>>
>> If these addresses should be your IPs vor Clients accessing the
>> Cluster, you must put tese IPs in your public_addresses file
>>
>>> OK, they are in the public_addresses file
>>
>> and in your DNS the hostname vor your cluster should point to both
>> addresses.
>>
>>> DOH! CNAME.
>>
>> Remeber that you have ti install "ethtool" on all nodes!
>>
>>> What do mean remember? I haven't seen it anywhere that you must
>>> install ethtool, It is installed anyway :-D
> I had an error-massage on the node without ethtool, and the nodes were
> unhealty. After I installaed ethtool it worked for me and the
> error-message was gone.

ethtool should be used by one of the eventscripts in ctdb.
The idea here is that ethtool is used in the script to check that the
link/interface that is used to host public addresses is good.
So that IF you unplug the cable,   or if the switch goes down,  then
the script/ethtool will detect that the node is bad  and the node
becomes UNHEALTHY.
When the node becomes unhealthy  all public ip addresses will be moved
over to other nodes that are not unhealthy.

I.e.  ethtool is to make sure that if the interface/link goes bad,
ctdb can detect it and take action.


>>
>> So if you start the cluster the system will pick an IP-Address out
>> of the file. If there is no public_addresses file your system will
>> not get any IP. If there is no ethtool but a public_address file,
>> the node cant set on of the IPs. If one node of your clusters fails
>> the second not will get the IP address from the failed host. BUT
>> REMEBER you wount see the IPs with "ifconfig" you MUST use "ip a
>> l".
>>
>>> That is something else that I haven't seen anywhere! :-)
> Read this:
> http://unix.stackexchange.com/questions/93412/difference-between-ifconfig-and-ip-commands
>
> What I think ist that CTDB is assaigning the virtual IP over "ip" and
> configuring the NIC with ethtool. So if you are setting an IP with the
> "ip" command, this address is not shown with "ifconfig"

The difference is more that ifconfig is a really old command from the
days when you could only have one ip address assigned to an interface.
As such   ifconfig will only show a single ip address,  even if there
are several addresses assigned.
(which ip it will show is kind of undefined)


ip addr show   is the command to use to show all addresses that are assigned.


>
> Did you get rid of the IP-Errormessage?
>
> I think that's your main problem.
>
> Stefan
>
>>
>>> Rowland
>>
>> Stefan
>>
>>
>> Am 16.12.14 um 10:30 schrieb Rowland Penny:
>>>>> On 16/12/14 07:53, Stefan Kania wrote:
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>>>>>> Hi Rowland,
>>>>>>
>>>>>> did you see that you have som Problems with IPs on node 1?
>>>>>> 2014/12/15 16:32:28.300370 [recoverd: 2497]: Failed to find
>>>>>> node to cover ip 192.168.0.9 2014/12/15 16:32:28.300412
>>>>>> [recoverd: 2497]: Failed to find node to cover ip
>>>>>> 192.168.0.8 I also had some problems with IP and
>>>>>> nameresolutions at the beginning. After I solved that
>>>>>> problem everything was fine.
>>>>>>
>>>>>> Stefan
>>>>>>
>>>>>>
>>>>>>
>>>>> I did wonder about those lines, I do not have 192.168.0.8 &
>>>>> 192.168.0.9, but Ronnie posted this:
>>>>>
>>>>> No, you should not/need not create them on the system. Ctdbd
>>>>> will create and assign these addresses automatically and
>>>>> dynamically while the cluster is running.
>>>>>
>>>>> So, do I need to create them and if so, where? This is one
>>>>> of those areas of CTDB that doesn't seem to documented at
>>>>> all.
>>>>>
>>>>> Rowland
>>>>>
>>
>> -- Stefan Kania Landweg 13 25693 St. Michaelisdonn
>>
>>
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>
> - --
> Stefan Kania
> Landweg 13
> 25693 St. Michaelisdonn
>
>
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