/** Send a heartbeat to the name-node. Ignore reply commands. */
void sendHeartbeat() throws IOException {
// register datanode
DatanodeCommand[] cmds =
nameNode.sendHeartbeat(
dnRegistration, DF_CAPACITY, DF_USED, DF_CAPACITY - DF_USED, 0, 0, null);
if (cmds != null) {
for (DatanodeCommand cmd : cmds) {
LOG.debug("sendHeartbeat Name-node reply: " + cmd.getAction());
}
}
}
/** Send a heartbeat to the name-node and replicate blocks if requested. */
int replicateBlocks() throws IOException {
// register datanode
DatanodeCommand[] cmds =
nameNode.sendHeartbeat(
dnRegistration, DF_CAPACITY, DF_USED, DF_CAPACITY - DF_USED, 0, 0, null);
if (cmds != null) {
for (DatanodeCommand cmd : cmds) {
if (cmd.getAction() == DatanodeProtocol.DNA_TRANSFER) {
// Send a copy of a block to another datanode
BlockCommand bcmd = (BlockCommand) cmd;
return transferBlocks(bcmd.getBlocks(), bcmd.getTargets());
}
}
}
return 0;
}