I am new to Linux and I am using Centos7 from AWS and I am slightly confused. To my understanding, in order to use sudo, you need to be in sudoers and by default, the root user and group wheel are in sudoers. I am currently the centos user and I can use sudo, but I can't understand why. I don't believe I am in the group wheel.
In cloud environments, many distributions (including CentOS 7) use cloud-init to configure the system when it first boots.
If we look at
/etc/cloud/cloud.cfg on the CentOS 7 cloud image, we find:
system_info: default_user: name: centos lock_passwd: true gecos: Cloud User groups: [wheel, adm, systemd-journal] sudo: ["ALL=(ALL) NOPASSWD:ALL"] shell: /bin/bash distro: rhel paths: cloud_dir: /var/lib/cloud templates_dir: /etc/cloud/templates ssh_svcname: sshd
This says, "create a user named
centos and apply the
ALL=(ALL) NOPASSWD:ALL to that user. This causes
cloud-init to create the file
/etc/sudoers.d/90-cloud-init-users with the content:
# Created by cloud-init v. 18.2 on Mon, 08 Aug 2022 22:07:23 +0000 # User rules for centos centos ALL=(ALL) NOPASSWD:ALL
And that is why the
centos user has