Hadoop HDFS Data Write Operations
HDFS的写流程图
i) The HDFS client sends a create request on DistributedFileSystem APIs.
hdfs客户端发送创建请求给DistributedFileSystem的api.
ii) DistributedFileSystem makes an RPC call to the namenode to create a new file in the file system’s namespace.
The namenode performs various checks to make sure that the file doesn’t already exist and that the client has the permissions to create the file. When these checks pass, then only the namenode makes a record of the new file; otherwise, file creation fails and the client is thrown an IOException. Also Learn Hadoop HDFS Architecture in Detail.
DistributedFileSystem 发送RPC(Remove Procedure Call)请求给namenode去文件系统的命名空间中创建一个新文件. namenode执行一系列检查去确定文件是否存在以及客户端是否有权限创建文件. 当检查完成后, 仅在namenode记录新文件. 否则, 文