[ClusterLabs] Fencing questions

[Klaus Wenninger]

On 5/9/19 1:03 PM, Lopez, Francisco Javier [Global IT] wrote:
> Good day guys !
>
> I'm implementing fencing in my two node cluster with this detail:
>
> - fence_vmware_soap
> - PostgreSql release 10.X
> - CentOS 7.X
>
> As far as I know, to create the resources, I can use two different ways:
>
> - Create only one resource for both nodes, following this way:
>
>   # pcs -f stonith_cfg stonith create fence_nodes \
>   fence_vmware_soap \
>   ipaddr=<VM_IP> \
>   ssl_insecure=1 \
>   login="<VM_user>" \
>   passwd="<VM_passwd>" \
>   action=reboot \
>   pcmk_host_list="node_01,node_02" \
>   power_wait=3 op monitor interval=60s
>
> - Create two different resources, one for each node, following this way:
>
>   # pcs -f stonith_cfg stonith create fence_node_01 \
>   fence_vmware_soap  \
>   ipaddr=<VM_IP> \
>   ssl_insecure=1 \
>   login="<VM_user>" \
>   passwd="<VM_passwd>" \
>   action=reboot \
>   pcmk_host_list="node_01" \
>   power_wait=3 op monitor interval=60s
>
>   # pcs -f stonith_cfg stonith create fence_node_02 \
>   fence_vmware_soap  \
>   ipaddr=<VM_IP> \
>   ssl_insecure=1 \
>   login="<VM_user>" \
>   passwd="<VM_passwd>" \
>   action=reboot \
>   pcmk_host_list="node_02" \
>   power_wait=3 op monitor interval=60s
>
>   With this method I understand I will have to add some constraints, etc.
>
> Said this, my questions are:
>
> - Which are the differences among them ? (if any).
> - Is there any recommended option and why ?
For your 2-node-cluster there might be a definite reason why you'd
like to have 2 fence-resources as to prevent fence-races when both
are still alive but just don't see each other. If you make one
wait a little longer to fence you can determine which one would
rather win.
If the aim is just to prevent that they fence each other at the same
time introduction of a random delay should be fine as well.
(That is pcmk_delay_max and if you want to further tailor the delay
with astatic delay component you can use pcmk_delay_base on top.)

Klaus
>
> Regards
> Javier
> Francisco Javier​ 	  	Lopez
>
> IT System Engineer 	 |  	Global IT
>
> O: *+34 619 728 249* <tel:+34%20619%20728%20249> 	 | 
> M: *+34 619 728 249* <tel:+34%20619%20728%20249> 	 | 
> 	*franciscojavier.lopez at solera.com*
> <mailto:franciscojavier.lopez at solera.com> 	 |  	*Solera.com*
> <https://www.solera.com/>
>
> Audatex Datos, S.A. 	 | 
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>
>  
>
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