The previous chapter covered the data loaders, which fetch the data before the route renders. This chapter covers the counterpart: the form actions, which handle the data mutations after the user submits a form. The loader is the read; the action is the write. In the React Router’s Data mode, the action function is defined…
The previous chapters covered the navigation, the routes, and the path and query parameters. This chapter introduces the mechanism that fetches the data before the route renders: the loader. In the React Router, the loader is a function defined on the route object. It runs before the component renders, and its result is available to…
The previous chapter covered the DNS client configuration, which determines how the system resolves the hostnames. This chapter covers the DHCP client, which determines how the system obtains the IP address, the default gateway, and the DNS servers automatically. The LFCS exam lists “Configure networking and hostname resolution statically or dynamically” under the Networking domain…
The previous chapters covered the web servers that respond to the HTTP requests. This chapter returns to the networking layer: the DNS client configuration. The LFCS exam lists “Configure DNS” and “Use tools to troubleshoot DNS issues” under the Networking domain . The DNS client configuration is the set of files and services that determine…
The previous chapter covered Nginx, the event-driven web server that is the default on many modern distributions. This chapter introduces Apache HTTP Server, the older and still widely deployed alternative. The LFCS exam lists “Configure an HTTP server” under the Service Configuration domain . Apache uses a process-based model: a parent process manages a pool…
The previous chapters covered the virtualization and containerization of the application environments. This chapter introduces the web server that often sits in front of those environments: Nginx. The LFCS exam lists “Configure an HTTP server” and “Restrict access to a web page” under the Service Configuration domain . Nginx is a high-performance, event-driven web server…
The previous chapter introduced KVM as a type-1 hypervisor that turns the Linux kernel into a virtualization layer. This chapter covers the practical management of virtual machines: creating them, controlling their lifecycle, adjusting their resources, and working with snapshots and disks. The LFCS exam tests the virsh commands and the virt-install syntax, along with the…
The previous chapters covered containerization with Docker, which isolates applications at the operating system level by sharing the host kernel. This chapter introduces the other major virtualization technology on Linux: KVM (Kernel-based Virtual Machine). KVM is a full virtualization solution that provides each guest with its own virtual hardware and its own kernel. The LFCS…
The previous chapter covered the basic commands: pulling images, running containers, and inspecting the state. This chapter focuses on the lifecycle of the images and the containers: how the image is built, how it is layered, how the container adds the writable layer, and how the data is preserved or lost. The LFCS exam tests…
The previous chapter covered the conceptual model: the client-server architecture, the image-container-registry triad, and the difference between containers and virtual machines. This chapter covers the commands that implement that model: pulling images, running containers, inspecting the state, executing commands inside the container, and cleaning up. The LFCS exam tests the command syntax, the flag semantics,…