Problem phenomenon:
When deploying hadoop-3.1.2, the following error occurred when starting hdfs:
Starting datanodes
zglinux: ERROR: Cannot set priority of datanode process 2905
solution:
This problem has been troubled for a long time, and it is not searchable on Baidu, and I have successfully deployed in the company's environment, and the deployment failed when I returned home. I was very annoyed. Therefore, after the settlement, I vowed to write this blog to warn future generations. Possible solutions:
- core-site.xml configuration error
core-site.xml configures the hadoop component hdfs (distributed file system). This datanode is a member of hdfs, so it may be caused by a configuration error in core-site.xml --- mine is not;
- hadoop-env.sh environment variable configuration problem
It is possible that HDFS_DATANODE_SECURE_USER=root is configured in the environment variable , which leads to the error --- mine is for this reason. As for this configuration, I don’t know for the time being. As for the configuration, it was because of the "installation manual" posted on the network. With this, it may be that I know it and don’t know why ...
# -------- for set priority if datanode process-----error
export HDFS_DATANODE_SECURE_USER=root
Log after error:
After configuring the above environment variables and reporting an error, a privileged-root-datanode-XXX.out file is generated in the log directory of hadoop, and the reason for the datanode error is recorded, as follows:
Based on this, the younger brother had doubts + inspiration on the configuration file, and thus came up with a solution.
Correct phenomenon:
Finally, I posted a correct result. I hope this will inspire everyone. I won’t write much about the installation of hadoop. There are a lot of them on the Internet. Thank you.
