[ClusterLabs] IP clone issue

Octavian Ciobanu coctavian1979 at gmail.com
Tue Sep 5 10:15:03 EDT 2017


Based on ocf:heartbeat:IPaddr2 man page it can be used without an static IP
address if the kernel has net.ipv4.conf.all.promote_secondaries=1.

"There must be at least one static IP address, which is not managed by the
cluster, assigned to the network interface. If you can not assign any
static IP address on the interface, modify this kernel parameter: sysctl -w
net.ipv4.conf.all.promote_secondaries=1 (or per device)"

This kernel parameter is set by default in CentOS 7.3.

With clone-node-max="1" it works as it should be but with
clone-node-max="2" both instances of VIP are started on the same node even
if the other node is online.

Pacemaker 1.1 Cluster from Scratch say that
"clone-node-max=2 says that one node can run up to 2 instances of the
clone. This should also equal the number of nodes that can host the IP, so
that if any node goes down, another node can take over the failed node’s
"request bucket". Otherwise, requests intended for the failed node would be
discarded."

To have this functionality do I must have a static IP set on the interfaces
?



On Tue, Sep 5, 2017 at 4:54 PM, emmanuel segura <emi2fast at gmail.com> wrote:

> I never tried to set an virtual ip in one interfaces without ip, because
> the vip is a secondary ip that switch between nodes, not primary ip
>
> 2017-09-05 15:41 GMT+02:00 Octavian Ciobanu <coctavian1979 at gmail.com>:
>
>> Hello all,
>>
>> I've encountered an issue with IP cloning.
>>
>> Based the "Pacemaker 1.1 Clusters from Scratch" I've configured a test
>> configuration with 2 nodes based on CentOS 7.3. The nodes have 2 Ethernet
>> cards one for cluster communication with private IP network and second for
>> public access to services. The public Ethernet has no IP assigned at boot.
>>
>> I've created an IP resource with clone using the following command
>>
>> pcs resource create ClusterIP ocf:heartbeat:IPaddr2 params nic="ens192"
>> ip="xxx.yyy.zzz.www" cidr_netmask="24" clusterip_hash="sourceip" op start
>> interval="0" timeout="20" op stop interval="0" timeout="20" op monitor
>> interval="10" timeout="20" meta resource-stickiness=0 clone meta
>> clone-max="2" clone-node-max="2" interleave="true" globally-unique="true"
>>
>> The xxx.yyy.zzz.www is public IP not a private one.
>>
>> With the above command the IP clone is created but it is started only on
>> one node. This is the output of pcs status command
>>
>> Clone Set: ClusterIP-clone [ClusterIP] (unique)
>>      ClusterIP:0    (ocf::heartbeat:IPaddr2):    Started node02
>>      ClusterIP:1    (ocf::heartbeat:IPaddr2):    Started node02
>>
>> If I modify the clone-node-max to 1 then the resource is started on both
>> nodes as seen in this pcs status output:
>>
>> Clone Set: ClusterIP-clone [ClusterIP] (unique)
>>      ClusterIP:0    (ocf::heartbeat:IPaddr2):    Started node02
>>      ClusterIP:1    (ocf::heartbeat:IPaddr2):    Started node01
>>
>> But if one node fails the IP resource is not migrated to active node as
>> is said in documentation.
>>
>> Clone Set: ClusterIP-clone [ClusterIP] (unique)
>>      ClusterIP:0    (ocf::heartbeat:IPaddr2):    Started node02
>>      ClusterIP:1    (ocf::heartbeat:IPaddr2):    Stopped
>>
>> When the IP is active on both nodes the services are accessible so there
>> is not an issue with the fact that the interface dose not have an IP
>> allocated at boot. The gateway is set with another pcs command and it is
>> working.
>>
>> Thank in advance for any info.
>>
>> Best regards
>> Octavian Ciobanu
>>
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>>
>
>
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