#Linux
69 posts
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.
Red Hat Certified Engineer (RHCE) #9 Tags and conditionals: when, loop, until
The ninth post in the Red Hat Certified Engineer (RHCE) series. We organize the core tools that control the flow of a playbook — conditional execution with when, iteration with loop, retries with until, and partial runs with tags. We learn the exam-staple patterns hands-on: branching by OS, bulk-creating a user list, retrying while waiting for a service to come up, and using tags to run only the tasks you need.
Red Hat Certified System Administrator (RHCSA) #6: Local Storage 2 — LVM Expansion and LUKS Encryption
The sixth post in the Red Hat Certified System Administrator (RHCSA) series. We add a PV to a volume group and grow it with vgextend, enlarge the logical volume with lvextend, then extend the file system itself with xfs_growfs and resize2fs — and we build a LUKS-encrypted volume with cryptsetup, setting it up to unlock automatically at boot through crypttab and fstab. We also cover exam staples like XFS being impossible to shrink.
Red Hat Certified Engineer (RHCE) #8 Error handling: block/rescue/always, failed_when, ignore_errors
The eighth post of the Red Hat Certified Engineer (RHCE) series. We cover the error handling that controls the flow when a playbook fails mid-run. From the exam point of view, we work through structuring exceptions with block/rescue/always, letting failures slide with ignore_errors, defining your own failure conditions with failed_when, and shoring up the idempotency of the command module with changed_when.
Red Hat Certified System Administrator (RHCSA) #5: Local Storage 1 — Partitions, swap, LVM basics
The fifth post in the Red Hat Certified System Administrator (RHCSA) series. We check disks with lsblk and fdisk, create partitions with fdisk,parted, add swap with mkswap,swapon, build LVM with pvcreate,vgcreate,lvcreate, then mount it permanently with mkfs and fstab (UUID) — all typed out by hand. We carry RHCSA's most common task, "create an LVM and mount it," all the way through so it survives a reboot.
Red Hat Certified Engineer (RHCE) #7: Jinja2 Templates — Filters, Control Flow, and lookup
The seventh post in the Red Hat Certified Engineer (RHCE) series. We render .j2 files into per-host configuration with the template module, cover Jinja2 syntax for variable output, for, and if, plus filters like default, upper, join, and to_nice_yaml, read files and environment variables with lookup, and even handle whitespace control — all in the form the exam asks for.
Red Hat Certified System Administrator (RHCSA) #4: Boot and the system — systemd, target, GRUB2, password recovery
The fourth post in the Red Hat Certified System Administrator (RHCSA) series. We work through the structure of systemd and how to control services with systemctl, switching the boot target, editing kernel parameters in GRUB2, and the single most frequent RHCSA task — root password recovery with rd.break — by typing the commands ourselves.
Red Hat Certified Engineer (RHCE) #6: Variables and facts — precedence, magic vars, custom facts
The sixth post in the Red Hat Certified Engineer (RHCE) series. From a hands-on angle, we cover where variables are defined (play vars, vars_files, group_vars/host_vars, extra-vars, register) and their reference syntax, the precedence rules where extra-vars always wins, the facts gathered by gather_facts and how to reach them through ansible_facts, how register stores a task result, magic variables like hostvars and groups, and finally custom facts you build under /etc/ansible/facts.d.
Red Hat Certified System Administrator (RHCSA) #3 Shell scripting: conditionals, loops, arguments, exit codes
The third post in the Red Hat Certified System Administrator (RHCSA) series. To write the simple bash scripts that show up regularly on the RHCSA exam, we type our way through shebang and variable quoting, positional arguments and exit codes, test/if/case conditionals and for/while/until loops, command substitution and arithmetic, read input and functions. At the end we write a real-world script that validates arguments and processes multiple targets in a loop.
Red Hat Certified Engineer (RHCE) #5: Playbook Basics — task, handler, idempotency
The fifth post in the Red Hat Certified Engineer (RHCE) series. We work through the YAML structure of a playbook and the play/task relationship, writing module tasks and the recommendation to name them, the handler-and-notify pattern that runs once at the end only when something changed, the idempotency that surfaces through changed and ok, the idempotency stopgaps for command/shell (creates/removes), and ansible-playbook versus ansible-navigator run plus --check/--diff/--syntax-check — all from a hands-on exam point of view.
Red Hat Certified System Administrator (RHCSA) #2 Essential Tools: bash, vi, redirection, find/grep, archive, ssh
The second post in the Red Hat Certified System Administrator (RHCSA) series. We cover the shell fundamentals that everything else is built on — input/output redirection and pipes, finding and processing matching files with find and grep, text processing with less,sort,sed,awk, the modes and search-and-replace of the vi editor, tar,gzip archiving, remote work with ssh and scp, and how to wield man pages as a weapon in an exam room with no internet — all with command examples.