Operating System User

ClusterControl controller (cmon) process requires a dedicated operating system user to perform various management and monitoring commands on the managed nodes. The value of os_user or sshuser in CMON configuration file, must exist on all managed nodes and it should have the ability to perform super-user commands.

You are recommended to install ClusterControl as ‘root’, and running as root is the easiest option. If you perform the installation using another user other than ‘root’, the following must be true:

• The OS user must exist on all nodes
• The OS user must not be mysql
• The sudo program must be installed on all hosts
• The OS user must be allowed to do sudo, i.e, it must be in sudoers
• The OS user must be configured with the proper PATH environment variable. The following environment PATH is expected for the user myuser: PATH=/usr/local/bin:/bin:/usr/bin:/usr/local/sbin:/usr/sbin:/home/myuser/.local/bin:/home/myuser/bin

For sudoers, using passwordless sudo is recommended. To set up a passwordless sudo user, open /etc/sudoers via text editor and add the following line at the end. Replace {OS user} with the sudo username of your choice:

{OS user} ALL=(ALL) NOPASSWD: ALL

Open a new terminal to verify if it works. You should now be able to run the following command without entering a password:

$ sudo ls /usr

You can also verify this with the SSH command line used by CMON (assuming passwordless SSH has been set up correctly):

$ ssh -qt {OS user}@{IP address/hostname} "sudo ls /usr"

where {OS user} is the name of the user you intend to use during the installation, and {IP address/hostname} is the IP address or hostname of a node in your cluster.