Permission Denied error while running start-dfs.sh
I also encountered the same thing, I did soI found that my pdsh default rcmd is rsh, not ssh, rsh and ssh remote login authentication is not the same, when installing hadoop I configured ssh localhost password-free login, but rsh is not possible.
so，try：
1.check your pdsh default rcmd rsh
pdsh -q -w localhostSee what your pdsh default rcmd is.
2.Modify pdsh's default rcmd to ssh
export PDSH_RCMD_TYPE=sshyou can be added to ~/.bashrc, and source ~/.bashrc
3.sbin / start-dfs.sh
Uninstall pdsh will solve this problem. I am working with Hadoop version 3.2.1 on Ubuntu 18.04.4 LTS.
I test start-dfs.sh on several fresh-installed virtual machines and one old VM. The command failed only on the old VM. I have tried the high-voted answer, and found that only the old VM has pdsh installed. So I uninstall this software, and after that the command executed successfully.
So, if you did not install pdsh for some purpose, you can try to uninstall it.
Try uninstalling pdsh
sudo apt-get remove pdsh
and then restart your hadoop by:
sudo start-dfs.sh
This is what worked for me.