Linux
Red Hat Certified Engineer (RHCE) #15 RHCSA Automation 2: Services, chronyd, log
The fifteenth post in the Red Hat Certified Engineer (RHCE) series. We automate the manual RHCSA work of service management, time synchronization, and log configuration with Ansible. We lock down daemons through enable and start in one shot with the service/systemd module, configure NTP with the timesync system role or a chrony template plus a handler, schedule jobs with the cron and at modules, and apply journald persistent storage and tuned profiles through playbooks.
Red Hat Certified System Administrator (RHCSA) #12: firewalld and SSH key authentication
The twelfth post in the Red Hat Certified System Administrator (RHCSA) series. We type through firewalld's zone concept and how to permanently allow services and ports with firewall-cmd, rich rules and source-based zone assignment, then how to set up SSH key authentication with ssh-keygen and ssh-copy-id and get the authorized_keys permissions right. We zero in on the RHCSA staples — permanently allowing ports and services and configuring key authentication — and the trap of forgetting --permanent.
Red Hat Certified Engineer (RHCE) #14 RHCSA Automation 1: Users/Groups, Packages/Repositories
The fourteenth post in the Red Hat Certified Engineer (RHCE) series. We automate the user/group creation and package/repository management you did by hand in RHCSA with Ansible modules. We work through the user and group modules, passwords handled safely with password_hash and Vault, the dnf module and module streams, the yum_repository module, and the exam-favorite pattern of creating many users at once with loop.
Red Hat Certified System Administrator (RHCSA) #11 Users/Groups: UID/GID, sudo, ACL, password policy
The eleventh post in the Red Hat Certified System Administrator (RHCSA) series. We organize it around the exact tasks RHCSA puts on the practical exam: creating users with useradd and usermod and assigning UID/GID, groupadd and supplementary groups, granting sudo rights through /etc/sudoers and visudo, setting per-file ACLs with setfacl, and pinning down password expiry policy with chage.
Red Hat Certified Engineer (RHCE) #13: System roles (rhel-system-roles)
The 13th post in the Red Hat Certified Engineer (RHCE) series. We cover how rhel-system-roles — a set of validated roles Red Hat ships — abstracts away RHCSA tasks. We walk through installation (dnf and ansible-galaxy collection), where the docs live (/usr/share/doc/rhel-system-roles) and the example-playbook copy pattern, the timesync/firewall/selinux/storage/network/postfix roles and their variables, and the exam regulars — automating NTP, firewall, and SELinux — with worked examples.
Red Hat Certified System Administrator (RHCSA) #10 Basic Networking: NetworkManager (nmcli), hostname, /etc/hosts
The tenth post in the Red Hat Certified System Administrator (RHCSA) series. We cover how NetworkManager manages networking on RHEL 9, how to create connections and set a static IP permanently with nmcli, how to change the hostname with hostnamectl and resolve names through /etc/hosts, and how to verify the result with the ip command — all typed out by hand. Setting a static IP so it survives a reboot is a perennial RHCSA exam task.
Red Hat Certified Engineer (RHCE) #12 Collection: Galaxy, Automation Hub
Part 12 of the Red Hat Certified Engineer (RHCE) series. We cover the concept of an Ansible collection and FQCN (namespace.collection.module), how to install collections and roles with ansible-galaxy, the way to install dependencies in bulk with requirements.yml, the difference between Galaxy and Automation Hub, and the collections_path setting in ansible.cfg — all from a hands-on exam point of view. We work through the exam staple of downloading a collection with requirements.yml and using it via FQCN as a worked example.
Red Hat Certified System Administrator (RHCSA) #9 System Operations: chronyd, journald, cron, systemd timer, tuned
The ninth post in the Red Hat Certified System Administrator (RHCSA) series. We set system time with timedatectl and chronyd, read and persist logs with journald and rsyslog, schedule jobs with cron and systemd timers, and tune system profiles with tuned — the operational tasks, organized around the commands you actually type on the exam.
Red Hat Certified Engineer (RHCE) #11: Writing and Using Roles
Part 11 of the Red Hat Certified Engineer (RHCE) series. We cover the standard role directory structure and ansible-galaxy role init, the difference between the roles key and include_role/import_role, why defaults sits at the lowest role variable precedence, and the dependencies in meta/main.yml plus roles_path. We practice the exam-favorite flow of writing a role and calling it from a playbook with worked examples.
Red Hat Certified System Administrator (RHCSA) #8 Packages and repositories: dnf, modules, AppStream
The eighth post in the Red Hat Certified System Administrator (RHCSA) series. We cover installing, removing, and searching packages with dnf, adding repositories, and working with AppStream module streams and profiles. From RHCSA staples like adding a specific repository and installing from it, all the way to switching module streams — all walked through with command examples.
Red Hat Certified Engineer (RHCE) #10 Ansible Vault: Managing Secrets
The tenth post in the Red Hat Certified Engineer (RHCE) series. We encrypt variable files with ansible-vault (create/edit/view/encrypt/decrypt/rekey), put secrets in group_vars/secret.yml and use them from a playbook, supply the password at runtime with --ask-vault-pass and --vault-password-file, and inline-encrypt a single variable with encrypt_string — all laid out command by command.
Red Hat Certified System Administrator (RHCSA) #7 File systems: XFS, ext4, mount/fstab, NFS, AutoFS
The seventh post in the Red Hat Certified System Administrator (RHCSA) series. We create file systems with mkfs.xfs and mkfs.ext4, handle mounts with mount/umount/findmnt, lock down persistent mounts that survive a reboot via UUID/LABEL and fstab, and finally type out NFS client mounts and AutoFS on-demand mounts by hand.