1. What is a high-availability load balancing
nginx as a load balancer, all requests to nginx, nginx seen in a very focused position, if nginx web server is down the back-end services will not be able to provide services, severely affected.
In order to shield down load balancing server, you need to create a backup machine. On the main server and backup machines are running high availability (High Availability) monitoring program, such as by sending "I am alive" this information to monitor each other's health. When the backup unit can not receive this information within a certain period of time, it will take over the primary server's IP service and continue to provide load balancing services; when the Backup Manager and from the main manager receives "I am alive" such information when it will release the IP address of the service, such as the primary server to provide load balancing service starts again.
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