Problem with cluster on centos 6.5

Hallo to everyone.From sometime i have problems with my asterisk pbx on cent os which is in corosync cluster mode with resource groups.The problem is for time the cluster just swap the active one with the other and the only messages in \var\log\messages is that bond0:link status defenitly down for interface eth0 and than up and down.no errors in any interface in ifconfig.Can you please tell me where to look for the reason.Thank you.

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