Architecture principle of hadoopHA

1. Install a NameNode on both nodes
2. There is a monitor (ZKFC) in the node where each NameNode is located
3. The monitor will monitor the status of the NameNode and register the node in zk
4. Who are the two NameNodes? If the registration is successful in zk first, whoever is in the active state, and the rest is in standby
5. If the active node hangs up, the monitor will cancel the node registered in zk
6. Once the monitor in standbv detects zk If the node disappears, it will immediately register and notify the NameNode in the standby state to start working. Standbv will first remotely execute the kill-9 port of the activeNameNode node to kill him, and then start switching to the active state to start working. 7. ActiveNameNode and standbyNameNode use JN to make
decisions copy from