Monitoring on OpenShift Virtualization Training

Guest agent

Mon, 01 Jan 0001 00:00:00 +0000

In many of the available cloud images, the qemu-guest-agent package is already installed. If it’s not preinstalled you can use one of the previously learned concepts to install the package.

Task 8.1.1: Start a virtual machine and explore guest agent information

In this lab we are going to reuse the virtual machine we created in the 4.2. Cloud-init lab.

Start the cloud-init virtual machine using the following command:

virtctl start lab04-cloudinit --namespace lab-<username>

The presence of the guest agent in the virtual machine is indicated by a condition in the VirtualMachineInstance’s status. This condition shows that the guest agent is connected and ready for use.

Readiness and liveness probes

Mon, 01 Jan 0001 00:00:00 +0000

Liveness and readiness probes can be configured for VirtualMachineInstances similarly to how they are defined for containers. You can find more information about these probes in Kubernetes’ documentation .

Liveness probes will stop the VirtualMachineInstance if they fail, allowing higher-level controllers, such as VirtualMachine or VirtualMachineInstanceReplicaSet, to create new instances that should be responsive.

Readiness probes signal to Services and Endpoints whether the VirtualMachineInstance is ready to handle traffic. If these probes fail, the VirtualMachineInstance will be removed from the list of Endpoints backing the Service until the probe recovers.

Prometheus monitoring

Mon, 01 Jan 0001 00:00:00 +0000

Prometheus is an open-source monitoring and alerting toolkit designed for reliability and scalability. It collects real-time metrics from services and systems, stores them in a time-series database, and provides powerful querying capabilities. Prometheus operates with a pull-based model, scraping metrics from endpoints at regular intervals. It supports multi-dimensional data through labels, enabling flexible queries and insights. Paired with tools like Grafana for visualization, Prometheus is widely used for monitoring cloud-native applications, infrastructure, and system performance, with built-in alerting to notify users of potential issues.

Prometheus Node Exporter

Mon, 01 Jan 0001 00:00:00 +0000

The Prometheus Node Exporter is a key component used for collecting operating system metrics from Linux and Windows systems. It exposes a wide range of system-level metrics that Prometheus can scrape, making it useful for monitoring the health and performance of physical and virtual machines.

Some of the key metrics collected by Node Exporter include:

CPU usage: Tracks how much CPU time is being used by user and system processes
Memory usage: Monitors free and used memory, swap space, and buffer/cache utilization
Disk I/O: Provides insights into disk read/write operations and storage usage
Network statistics: Captures metrics on data sent and received over network interfaces
File system usage: Monitors available and used space on file systems

Node Exporter runs as a lightweight daemon on each node and is easy to install and configure. It works out of the box, exposing most common system metrics through the /metrics endpoint, but can also be extended with additional collectors to gather more specialized data. These metrics can be visualized through tools like Grafana, helping administrators monitor and troubleshoot infrastructure performance.