Kubernetes offers a seamless, distributed solution for managing application workloads hosted across cluster nodes. According to the Cloud Native Computing Foundation’s most recent data, Kubernetes is the leading container orchestration system, with 69% of respondents using Kubernetes in production.
Kubernetes offers many benefits, including improved productivity for engineering teams, efficient autoscaling, and cost savings.
And because a Kubernetes ecosystem comprises multiple machines (nodes) working together within the same subsystem (cluster), making all of these elements observable is a key aspect of maintaining operational efficiency.
In this post, we’ll explore the topic of Kubernetes monitoring, including a brief analysis of some challenges, an overview of the most important metrics to monitor, and some best practices implemented by leading engineering organizations. In addition, we highlight several open-source and commercial tools that allow administrators to monitor component health within a cluster, as well as application performance for the end user.
The Challenge of Monitoring in Distributed, Containerized Systems
Kubernetes is incredibly useful in that it abstracts away a lot of complexity in order to speed up deployment. But because of this, engineers are often left in the dark about how resources are being used — it’s hard to tell what is actually happening.
Containers help package responsive, highly available applications as executable units that allow OS-level abstraction. By design, this enables a distributed framework of containerized applications and services that makes monitoring more intricate. Microservices architectures and stateless application design have many benefits; however, these modern software practices tend to lead to dynamic application architectures, which hinder observability. This limited observability makes troubleshooting issues with Kubernetes more complicated.
Kubernetes clusters make use of a number of components and processes that further complicate things: traditional machine monitoring mechanisms are ineffective for checking performance parameters of a dynamically transient services-oriented architecture.
And while the Kubernetes Dashboard allows users to access information on resource utilization, it does not include some of the refined mechanisms needed for monitoring ephemeral application workloads. This is why various mechanisms have been developed to improve monitoring and event logging in Kubernetes clusters.
What Metrics Are Monitored in Kubernetes
The best monitoring strategies closely track several metric types, depending on the components being observed. These are:
- POD/Container Metrics: These metrics help administrators check for resources allocated to every POD in a cluster. This enables them to see whether containers are over-or under-provisioned. Some common container metrics include CPU usage, memory usage, disk usage, and network traffic bandwidth, while common POD metrics include deployment progress, POD health, network data, and the number of running instances.
- Node Metrics: Every node running in a Kubernetes cluster has definite storage, memory, and CPU capacity to be used by PODs and cluster resources. Observing these metrics includes node-level consumption of storage and network bandwidth.
- Cluster Metrics: These metrics encompass data on the performance of a cluster’s control plane components. The performance data of master node components like the API Server, Scheduler, Controllers, and etcd server help to ensure cluster components run in the desired state.
- Application Metrics: These metrics are developed within an application’s code and are written to meet the requirements of the business case. A database application, for instance, can provide performance information on query latency and table storage. Such metrics are usually exposed to Kubernetes monitoring tools through an application programming interface (API).
10 Best Practices for Monitoring and Observability in Kubernetes
To make the most of a Kubernetes monitoring solution, it’s important to follow practices that provide valuable insights. Some of these include:
- Enforce deep visibility to make sure every cluster component is observable.
- Pick an appropriate instrumentation strategy using libraries and sidecar agents so that all critical metrics are collected without fail.
- Include event logs and historical performance data so that team members can easily trace the root causes of performance problems.
- Constantly monitor Kubernetes control plane elements to validate the performance of cluster services.
- Find a toolset that makes for easy and quick correlations between data, including metrics to events, events to logs, and traces to logs.
- Pick a toolset that provides anomaly detection or intelligent alerting, to avoid alert fatigue. And set alerts only on truly meaningful changes or events.
- Use a managed service if open-source, for example, a managed Prometheus offering from AWS or GCP, in order to avoid spending time monitoring your monitoring.
- Choose a SaaS monitoring solution that can be deployed as code for easier maintenance and management.
- Understand the costs early. If you are using a SaaS solution, take time to estimate what it will cost, including all charges like metric volume, log ingest, and per-seat pricing.
- Use a toolset that allows for user permissions and role-based access controls. For example, some tools allow users to designate permissions at the cluster and namespace levels.
Methods of Collecting Data
Kubernetes offers two main approaches for collecting data on running clusters: DaemonSets and the Metrics Server.
- A DaemonSet is a Kubernetes object that ensures a number of nodes in the cluster run a copy of a POD. These PODs are used to monitor nodes and collect logs on POD events. This data can then be passed to advanced monitoring solutions for further analysis.
- The Metrics Server is a POD that collects resource consumption data from the Kubelet service on each node and exposes this data to the ‘apiserver’ using the Metrics API. This data can then be used to autoscale an application and adjust resources to be used by containers.
Popular Tools for Kubernetes Monitoring & Observability
ContainIQ | A Kubernetes Native Solution
Developed and launched publicly in 2021, ContainIQ is a commercial tool for Kubernetes monitoring, logging, and tracing. ContainIQ is offered both as SaaS and as an on-prem or in-cloud offering. ContainIQ collects core metrics, events, logs, and traces all with a simple out-of-the-box approach. Users are able to search and filter views based on the cluster, namespace, and date range, and use a number of additional filters specific to each dashboard, like protocol and message.
ContainIQ is helpful for debugging issues that happen, maintaining cluster health, and alerting about issues that might cause performance degradation for end users. ContainIQ offers a number of pre-built dashboards that do not require additional configuration. Setting alerts is relatively straightforward and can be done on metrics, events, log messages, latency, and individual requests. Alerts can be sent using a simple Slack channel integration or to a large number of destinations using a webhook. ContainIQ’s SaaS offering is available via a self-service sign-up, and pricing is based on usage.
Open-Source Tools
Prometheus and Grafana
Developed by SoundCloud, Prometheus is an open-source toolkit that supports the instrumentation, collection, and storage of Kubernetes metrics. Prometheus collects and stores cluster performance data, and then it exposes this data through a Prometheus web user interface that lets administrators access, present and chart the collected information. As an extended monitoring layer, Grafana offers a visualization tool that accesses the Prometheus server using Prometheus Query Language (PromQL) for a more comprehensive analysis of performance data. Alertmanager is the popular alerting feature set available in Prometheus.
Prometheus has a large and growing open-source community and offers a large number of integrations with other tools. Prometheus can be self-hosted or can be run as a managed solution by the cloud providers, such as AWS and GCP, and by a number of third-party providers.
As mentioned earlier, Prometheus is often used with Grafana as a visualization tool. Grafana, another open-source project, can be self-hosted or can be used as a SaaS offering with Grafana Cloud.
cAdvisor
Container Advisor (cAdvisor) is an open-source metrics collection agent specifically built for containers. This solution runs at a node level, since it comes integrated with the kubelet service as one of the binaries. cAdvisor gathers data on CPU usage, memory usage, network status, and storage for every live container, helping administrators gain insight into machine-level performance metrics.
Kubernetes Dashboard
Through a web-based user interface, Kubernetes helps administrators manage cluster resources and troubleshoot containerized applications. The dashboard displays an overview of running applications within the cluster. Administrators can also access information on the state of cluster resources, including errors and other events that may affect application performance.
Jaeger
Originally released in 2016, Jaeger is an open-source project that provides a toolset for tracing and troubleshooting. For engineering teams with complex distributed systems, Jaeger makes it easy to perform distributed transaction monitoring and to perform root cause analysis. Jaeger is also helpful in that it can be used to monitor performance and latency optimization. It’s recommended that you instrument your applications using OpenTelemetry, and there is support for Java, Node, Python, Go, and C++.
Final Thoughts
While Kubernetes makes it easier to run distributed, containerized workloads, there is added complexity in handling distributed and connected compute elements. In this kind of complex setup, monitoring all critical components ensures that there are no single points of failure within a cluster.
Administering Kubernetes requires a focused approach, dedicated tools, and the right methodologies for proactive monitoring of cluster components. By enabling an efficient monitoring mechanism, organizations can not only increase cluster efficiency but also reduce operational costs while proactively managing resources at their optimum standards.
Photo by Miguel A. Amutio on Unsplash
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