Example using HAProxy and Keepalived on CentOS 7.3 Configure HAProxy and Keepalived on CentOS 7.3 to provide VxFlex OS Gateway high availability. This section describes how to configure a system running on CentOS 7.3, with the Keepalived open source tool used for the keep-alive component. For more information about Keepalived, see http://www.keepalived.org. For more information about CentOS, see the product documentation. Child TopicsConfigure the firewallIf the firewall is active, you must allow ports. If firewalld and selinux are disabled, skip this section. Prepare the VxFlex OS GatewayPrepare the VxFlex OS Gateway to enable HA on CentOS 7.3 servers. Configure HAProxy systems Configure the HAProxy systems, which serve as a load balancer for the VxFlex OS Gateway, monitoring the VxFlex OS systems and redirecting traffic if a node goes down. Create self-signed certificates for HAProxy If not using certificates from a CA, you must generate self-signed certificates for the nodes running HAProxy.