A.Keep the root account passwords of all hosts in the cluster consistent

B.It is not possible to manually switch between active and standby OMS during the upgrade process

C.Keep the network open. Avoid abnormal upgrades due to network problems

D.Expansion cannot be done during the observation period

A.The blue is a topic of Kafka, which can be understood as a queue, and each grid represents a message.

B.Consumer uses offset to record the read position

C.The messages generated by the producer are placed at the end of the topic one by one.

D.The consumer reads the messages sequentially from right to left.

A.Follower synchronizes data from Leader by pulling

B.Replicas are based on partitions. Each partition has its own master copy and slave copy

C.The master copy is called Leader, and the slave copy is called Follower

D.Both consumers and producers read and write data from Leader, and can also directly interact with Follower

A.True

B.False

A.In a highly reliable stand-alone database

B.In the local file system

C.In the memory of JobManager

D.In HDFS