Latest Articles - Page 28

Update the kernel safely on RHEL with DNF. Check available versions, install the latest kernel, verify the default boot entry, reboot, and confirm the new kernel.

Learn RHEL patch management with DNF: identify security advisories and CVEs, apply security-only updates, patch specific RHSA or CVEs, and verify remediation.

Fix "There are no enabled repositories" on RHEL by checking DNF repositories, system registration, BaseOS/AppStream, Subscription Manager, and offline repository configuration.

Remove old Linux kernels safely on RHEL, Rocky Linux and AlmaLinux with dnf remove --oldinstallonly, protecting the running kernel and a bootable fallback.

Downgrade an installed RPM package on RHEL-family systems with dnf downgrade, install an exact older build, handle common errors, and lock the version with versionlock.

To exit full screen in virt-manager, move the pointer to the top-center edge and click the hidden restore button. Learn why Ctrl+Alt+F may not work.

Rebuild the initramfs image with dracut for one kernel or every installed kernel, add storage and network drivers, and inspect the result with lsinitrd.

Learn how to check open and listening ports in Linux with ss, lsof, nmap, and nc. Find the process using a port and test remote port access.

Learn how to list running processes in Linux with ps, top, pgrep, and pstree. Filter processes by user, PID, name, CPU, memory, and state.

Scan-first Terraform cheat sheet for CLI commands, configuration files, HCL syntax, variables, expressions, count and for_each, state and import, modules, workspaces, and debugging — with links to full tutorials.

Learn what Terraform state is on Ubuntu — terraform.tfstate purpose, configuration vs real infrastructure, terraform show and state list, drift, sensitive data, Git rules, local vs remote state, and a full local_file …

Learn Terraform providers on Ubuntu — required_providers, provider blocks, aliases, terraform init installation, terraform providers, local and Docker examples, and common provider errors without cloud credentials.

Learn terraform destroy on Ubuntu with the Docker provider — provision disposable resources, preview with plan -destroy, confirm or auto-approve teardown, use -target safely, and understand state and configuration after …

Learn terraform validate on Ubuntu — what it checks, syntax and schema errors with real output, validate -json for automation, init -backend=false for CI, and how validate differs from plan and fmt.

Learn terraform fmt on Ubuntu — rewrite .tf files to canonical style, use -check and -diff, format recursively, enforce formatting in CI, and see how fmt differs from terraform validate.

Learn terraform apply on Ubuntu with the Docker provider — interactive approval, saved plans, -auto-approve, -var and -var-file, in-place updates, -replace, partial failure behavior, and independent resource …

Learn terraform plan on Ubuntu with the Docker provider — read execution plan output, preview create/update/replace/destroy, save plans with -out, and use -var, -destroy, -refresh-only, -detailed-exitcode, -target, and …

Learn what terraform init does on Ubuntu — backend and provider setup, module downloads, .terraform directory, .terraform.lock.hcl, common flags, and when to reinitialize a working directory.

Learn Terraform HCL syntax on Ubuntu — blocks, labels, arguments, expressions, comments, .tf and .tf.json files, multi-file layouts, terraform fmt, validate, and common syntax errors with real fixes.

Prepare a single Ubuntu VM with Docker, helper tools, isolated Terraform working directories, and optional plugin cache so you can practice init, plan, apply, and destroy without cloud credentials.

Install Terraform on Ubuntu 26.04 from the official HashiCorp apt repository, verify with terraform version, install a specific package version or upgrade, install the release binary with checksum verification, and …

Learn what Terraform is and how infrastructure as code works — declarative configuration, providers, resources, state, the init plan apply workflow, realistic use cases, and a local example on Ubuntu without a cloud …

Learn how Terraform works architecturally on Ubuntu — configuration, Terraform Core, provider plugins, dependency graphs, how state differs from desired configuration, what init plan and apply do internally, resource …

Organize Terraform in HCP Terraform on Ubuntu — how a workspace holds one collection of infrastructure with its own state and runs, how projects group and scope those workspaces, how HCP workspaces differ from Terraform …

Supply values to HCP Terraform runs from an Ubuntu host — how Terraform variables differ from environment variables, how workspace variables and variable sets at workspace, project, and organization scope combine, the …

Connect the Terraform CLI to HCP Terraform on Ubuntu — authenticate with terraform login, add a cloud block, initialize a CLI-driven workspace, trigger remote plan and apply runs that stream to your terminal, confirm …

Understand HCP Terraform governance on Ubuntu — how teams and permissions scope access across organization, project, and workspace levels, how Sentinel and OPA policy sets evaluate plans, why teams use the private …

Learn what git reflog is and how to use it with practical examples. Recover commits after git reset --hard, restore amended commits, recover deleted branches, inspect stash reflog, and understand reflog expiration …

Use git show to inspect a commit, read a file at a past revision, view tag metadata, and print low-level Git objects — with tested examples on Ubuntu and a side-by-side comparison with git log and git diff.

Pass default and aliased provider configurations into Terraform child modules on Ubuntu — provider requirements versus configurations, automatic inheritance, providers meta-argument mapping, configuration_aliases, count …