Hadoop HDFS DataNode
A DataNode manages the storage attached to the node it run on. There are usually one DataNode per node in the cluster. HDFS exposes a file system namespace and allows user data to be stored in files. Internally, a file is split into one or more blocks and these blocks are stored in a set of DataNodes. The DataNodes also perform block creation, deletion, and replication upon instruction from the NameNode.
To provide a fast failover in a Higth Availabity (HA) enrironment, it is necessary that the Standby node have up-to-date information regarding the location of blocks in the cluster. In order to achieve this, the DataNodes are configured with the location of both NameNodes, and send block location information and heartbeats to both.
module.exports = -> 'check': [ 'ryba/hadoop/hdfs_dn/check' ] 'configure': [ 'ryba/hadoop/core' 'ryba/hadoop/hdfs_dn/configure' ] 'install': [ 'masson/core/iptables' 'ryba/hadoop/core' 'ryba/hadoop/hdfs_dn/install' 'ryba/hadoop/hdfs_dn/start' 'ryba/hadoop/hdfs_dn/check' ] 'start': 'ryba/hadoop/hdfs_dn/start' 'status': 'ryba/hadoop/hdfs_dn/status' 'stop': 'ryba/hadoop/hdfs_dn/stop'