Ubuntu tutorials - Page 6

Learn Terraform local values on Ubuntu — locals block syntax, local.NAME references, derived values from variables, maps, functions, conditionals, multiple locals blocks, locals vs variables, and common errors on …

Learn Terraform output values on Ubuntu — output block syntax, resource attributes, terraform output, -raw, -json, jq, sensitive and complex outputs, state storage, shell automation, and common output errors on Terraform …

Learn Terraform input variables on Ubuntu — variable block syntax, types, terraform.tfvars, auto.tfvars, -var-file, -var, TF_VAR, CLI variable precedence on Terraform 1.15.8, validation, nullable, sensitive, and common …

Learn Terraform resource references and dependencies on Ubuntu — implicit ordering from attribute references, explicit depends_on, terraform graph, file-order vs graph order, dependency cycles, unknown values during …

Learn Terraform data sources on Ubuntu with the Docker provider — data block syntax, query existing infrastructure, attribute references, feeding values into resources, resource vs data comparison, depends_on, count and …

Learn the Terraform resource block on Ubuntu — syntax, type and local name, arguments and attributes, addresses and references, create and update with terraform_data, Docker verification, replacement and deletion, …

Learn how Terraform provider version constraints, .terraform.lock.hcl, terraform init -upgrade, and terraform providers lock work on Ubuntu — with required_version vs required_providers explained and real lock-file …

Learn Terraform data types on Ubuntu — string, number, bool, list, set, map, tuple, object, optional attributes, any, null, list vs set, map vs object, type conversions, terraform console type(), and common type errors …

Manage Linux users and groups with useradd, usermod, userdel, groupadd, primary and supplementary groups, account defaults, and ownership checks.

Configure Chrony NTP on Linux, verify time synchronization with chronyc, force clock correction, troubleshoot sync problems, and optionally serve LAN clients.

Learn the Linux boot process from UEFI or BIOS through GRUB, the kernel, initramfs, and systemd, with inspection commands and troubleshooting.

Use perf stat, perf record, and perf report on Linux to find CPU bottlenecks, collect call graphs, and resolve symbols with debuginfod on Rocky Linux, RHEL, Debian, Ubuntu, and other distributions.

Learn how to check ML-KEM support in TLS, create ML-DSA signatures, and verify post-quantum SSH key exchange on Linux, with tested Rocky Linux examples.

When a Linux VM shows the wrong time after every reboot, trace the clock from the virtual RTC through chrony, identify the selected NTP source, and fix stale RTC values, unsuitable chrony sources, or hypervisor time-sync …

Configure Apache HTTP Server to authenticate and authorize users with OpenLDAP using mod_authnz_ldap, group restrictions, TLS, and practical troubleshooting.

Fix missing Bash history commands in Linux, including commands lost across multiple terminals, delayed .bash_history writes, HISTCONTROL exclusions, and permission problems.

Create a Linux man page with a reusable groff template. Learn man sections, macros, local preview, system and user installation, mandb, whatis, and troubleshooting.

Create a system-level systemd service that starts at boot and runs as a dedicated non-root user and group on Ubuntu, Debian, Fedora, RHEL, Rocky Linux, AlmaLinux, CentOS Stream and Oracle Linux.

Restart or reload cron in Linux with systemctl restart cron on Ubuntu and Debian or crond on RHEL and Rocky Linux, and when a reload is actually needed.

Compare the RHEL and Debian Linux families, including RPM vs DEB, DNF vs APT, repositories, release models, lifecycle, security, support, configuration, cloud images and server use cases.

Learn how Unix, Linux, GNU/Linux and Linux distributions relate, why Ubuntu, Debian, Fedora, RHEL, Rocky Linux and Arch differ beyond desktop themes, and how to identify your distro from the shell.

Fix curl error 60 and similar HTTPS failures on Linux when corporate SSL inspection replaces public certificates with a private root CA trusted on Windows but missing from the Linux trust store.

Migrate an already-installed Ubuntu LVM root volume group onto a new LUKS2 physical volume with pvmove, then configure crypttab with initramfs, regenerate the initramfs, and update GRUB for boot-time unlock.

Use systemd-cryptenroll on LUKS2 volumes to add TPM2, FIDO2, PKCS#11, and recovery-key unlock methods, store token metadata in the LUKS2 JSON area, and wire boot unlock through crypttab.

Extend or shrink a LUKS2 ext4 volume on Linux: grow the partition first, run cryptsetup resize on the mapper, then resize2fs; for shrink, reverse the order with offline resize2fs and --size in 512-byte sectors.

Unlock and mount a LUKS USB or moved disk on another Linux host: cryptsetup open by device, UUID=, or /dev/disk/by-uuid, ext4 or LVM inside LUKS, read-only rescue mount, and close the mapper.

Configure crypttab and fstab to unlock and mount a secondary LUKS data partition at boot on Ubuntu or Debian.

Back up and restore a LUKS2 header with cryptsetup luksHeaderBackup and luksHeaderRestore, use a detached header file, and understand when a header copy cannot recover a forgotten passphrase.

Rotate LUKS passphrases and key slots, change cipher or volume key with cryptsetup reencrypt on LUKS2, and back up the header before destructive operations.

Encrypt a new Linux disk partition with LUKS2 using cryptsetup: partition the disk, run luksFormat, open the mapper, create ext4 on /dev/mapper, and mount the volume.