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Red Hat Virtualization 4.3 includes several improvements related to Cockpit, but the updates are relatively minor and, for the most part, the Cockpit implementation in RHV has changed very little. Even so, you should understand Cockpit, especially as it relates to the RHV environment.
Cockpit is lightweight, easy to use and can run on a variety of Linux distributions, such as Red Hat Enterprise Linux (RHEL), which serves as the foundation for RHV. The tool builds on existing server functionality, using the server's own APIs without requiring special infrastructure or configurations.
When not in use, Cockpit does not consume processing or memory resources, nor does it store data or rely on preconfigured templates. To use Cockpit, you need only sign in with your existing RHV credentials.
Cockpit runs on managed hosts within the RHV environment. You can access Cockpit's features through a user-friendly, web-based interface, which includes a comprehensive dashboard for gaining immediate insight into a host's health. You can also use the interface to monitor system resources, adjust configuration settings and troubleshoot potential problems.
Cockpit can run alongside other management tools and does not take over a server in any way, nor does it make any security decisions. The interface always reflects a server's current state, making it possible to diagnose and respond to issues throughout a system, including hosted VMs.
RHV and Cockpit basics
RHV is an enterprise-grade virtualization platform made up of several components. One of the most important components is the RHV Manager, a Linux service that provides a GUI and RESTful API for managing resources in an RHV environment. The RHV platform also includes a shared storage service for storing data associated with VMs, as well as a data warehouse service for collecting configuration and statistical data from the RHV Manager.
In addition, an RHV environment includes one or more hosts collected into a cluster. Each host acts as a KVM hypervisor that provides a platform for that host's VMs. The host also runs the virtual desktop service manager agent, which enables the RHV Manager to control VMs and collect performance data.
RHV supports two types of hosts: those running RHEL and those running RHV Hosts (RHV-H), which is a minimal OS based on RHEL. RHV built RHV-H for easy deployment and management, and it works well as an RHV host. RHV installs Cockpit by default on RHV-H but not on RHEL.
You can use Cockpit to perform administrative tasks, such as configuring network settings, on any of the managed hosts, whether RHEL or RHV-H. In addition, you can run terminal commands directly through the Cockpit interface as well as deploy an RHV self-hosted engine configuration, one of two configurations supported by RHV. A configuration determines how the system deploys the RHV Manager in the RHV environment.
You can deploy an RHV environment in a stand-alone Manager configuration or a self-hosted engine configuration. In a stand-alone Manager configuration, RHV installs the RHV Manager on an RHEL 7 physical machine or VM separate from the managed hosts.
In a self-hosted engine configuration, the RHV Manager runs in a VM on one of the managed hosts. In other words, the RHV Manager resides in the same environment that it manages. The host that contains the VM is known as the self-hosted engine node. To ensure high availability, you must implement at least two self-hosted engine nodes within the same environment.
The advantage of the self-hosted engine configuration is it requires one less physical server compared to the stand-alone Manager configuration. However, it also comes with additional administrative overhead.
To implement a self-hosted engine configuration, Red Hat recommends you use Cockpit, which requires set up of an initial deployment host. The host can be an RHV-H server or RHEL server. In either case, the host serves as the first self-hosted engine node in your RHV environment.
If you're using a RHEL server for the deployment host, you must manually install Cockpit and then enable and start the cockpit.socket service. Once Cockpit is up and running, you can use it to install and configure the RHV Manager, and then use the RHV Manager to add more self-hosted engine nodes as well as regular KVM nodes.
Cockpit in action
You can use Cockpit to manage both RHVH and RHEL nodes regardless of the RHV configuration. The Cockpit interface has been specifically tested on Mozilla Firefox, Google Chrome and Microsoft Edge, but you can generally access the interface through other browsers.
You can launch the Cockpit interface through the Administration Portal by selecting the target host in the portal. This launches the Cockpit login page in a new browser window. From the Cockpit interface, you can view a variety of system information. For example, you can access details about CPU usage, memory usage, disk I/O and network traffic, as well as information on the host OS and hardware. You can also view information about system services and logs. In addition, Cockpit enables you to generate reports with configuration and diagnostic information.
You can also use Cockpit to carry out a number of administrative tasks related to the system's services, network settings and local user accounts, as well as the host's VMs. For example, you can start, pause or resume a VM, create a VM from a template or migrate a VM to a different host.
You can use Cockpit without impacting the hosts or the RHV environment. Even if you don't use Cockpit to implement a self-hosted engine configuration, you can still use it for host management. All you need to do is connect to Cockpit through your browser. You don't have to take any special steps or change any configuration settings.