This article explains the correct ways to view container logs in Kubernetes, covering the underlying storage mechanism, kubectl log commands, log rotation, distributed log collection architectures like EFK and Loki, best‑practice recommendations, and detailed troubleshooting steps for common log‑related issues.
This article provides a comprehensive analysis of containerd and CRI‑O as Kubernetes container runtimes, covering their architectures, feature sets, installation procedures, migration strategies, performance benchmarks, best‑practice configurations, troubleshooting tips, and monitoring approaches to help operators decide which runtime best fits a production environment.
This article examines why many Kubernetes failures stem from the container runtime layer, explains the responsibilities of Docker, containerd, runc, and CRI, and provides production‑grade architectures, tuning guidelines, migration steps, security hardening, and observability practices to keep clusters stable and performant.
This article walks Kubernetes operators through a systematic investigation of NotReady node symptoms, explaining the kubelet status mechanism, detailing each diagnostic step—from verifying node conditions with kubectl to checking kubelet, container runtime, resources, network, and certificates—and providing concrete remediation and preventive measures.
A recent K8s host‑level deployment triggered massive service timeouts because runc 1.1.5 passed incorrect CPU‑binding masks to systemd, causing containers to share cores, inflating load and starving workloads, a problem uncovered with Perfetto, BPF tracing and a targeted bug‑fix upgrade.
Netflix discovered that scaling hundreds of containers on modern CPUs hit severe lock‑contention due to mount‑related kernel locks, with performance varying across AWS instance types, NUMA designs, and hyper‑threading, leading them to redesign containerd mounting and choose hardware‑aware scheduling to restore efficient scaling.
This guide introduces nerdctl, a Docker‑compatible command‑line tool built on containerd, outlines its key features, shows how to install it via binaries or package managers, and provides practical examples for running containers, building images, and using Docker Compose.
This article provides a comprehensive overview of the core container technologies—Docker, containerd, runc, and Kubernetes—explaining their evolution, relationships, component roles, runtime layers, security options, and practical recommendations for choosing the right runtime in development and production environments.
Learn a step‑by‑step process for migrating Kubernetes clusters (v1.24+) from the deprecated Docker runtime to the native Containerd CRI, covering compatibility checks, node preparation, installation, configuration, node draining, kubelet updates, validation, and common pitfalls such as cgroup driver mismatches.
This article explains how Docker relies on Linux kernel features to isolate processes, introduces containerd as an industrial‑grade container runtime, compares their logging, configuration, CNI handling, and command interfaces, and provides practical tables and examples for migrating from Docker to containerd in Kubernetes environments.
This article introduces nerdctl, a Docker‑compatible CLI built on containerd, outlines its key features, installation methods, and essential commands—including image building and Docker Compose support—providing developers and sysadmins a lightweight alternative for advanced container management.
This article recounts how our team, after repeated Docker daemon failures on a 500‑node Kubernetes cluster, performed a zero‑downtime migration to Containerd, detailing architectural differences, preparation steps, migration procedures, performance benchmarks, post‑migration adjustments, common pitfalls, and best practices for large‑scale production environments.
This guide shows how to map a low‑level containerd task ID to the corresponding Kubernetes Pod using ctr, kubectl, and jq commands, then provides step‑by‑step debugging actions such as pod inspection, log retrieval, and resource checks to quickly resolve container issues.
This guide walks you through preparing three AlmaLinux servers, disabling firewalls and SELinux, installing Containerd as the CRI, adding Kubernetes repositories, installing kubeadm, kubelet and kubectl, configuring the runtime, and verifying each component so you can confidently bootstrap a production‑ready Kubernetes cluster.
When deploying a Kubernetes cluster with kubespray and the NVIDIA runtime, Containerd 2.x reports "nvidia‑smi not found" because the go‑toml v2 parser treats the "binaryName" key differently, causing the wrong runtime wrapper to be used; the article details the configuration inspection, version comparison, code demonstrations, and practical work‑arounds.
This guide walks you through setting the download region, installing KubeKey and required dependencies, generating a configuration file, creating a single‑node or multi‑node Kubernetes cluster with containerd, and verifying the deployment using kubectl, all with clear command examples and screenshots.
Kubernetes 1.24 removed the Docker shim, prompting users to adopt Containerd, and this article compares Docker and Containerd commands, logs, configuration differences, and CNI networking, highlighting how Containerd interacts directly via CRI and reduces bugs.
This article explains what containerd is, why it is needed, its technical goals and architecture, provides step‑by‑step installation on Ubuntu, shows how to configure it as a system service, and demonstrates a complete Go program that creates, runs, and cleans up a Redis container using the containerd client library.
This guide walks through moving a Docker‑Compose‑defined web front‑end and MySQL back‑end to a Kubernetes cluster using containerd as the runtime, covering essential tools, conversion commands, container‑keep‑alive tricks, external service access, and common troubleshooting steps.
This article provides a comprehensive overview of container technology, covering its definition, key characteristics, historical evolution from early virtualization to modern Docker and Kubernetes ecosystems, core Linux mechanisms such as cgroups and namespaces, runtime implementations, OCI standards, security enhancements, and container orchestration.
This guide explains why many organizations are moving from Docker to the lighter, more efficient containerd runtime in Kubernetes, outlines the benefits such as performance, security, and simplified architecture, and provides detailed preparation steps and migration commands to ensure a smooth transition.
In a Kubernetes cluster the kube-scheduler pod may stay pending due to a container-name reservation conflict; this guide shows how to locate the offending container with ctr, delete it, restart kubelet, and verify that the pod returns to Running state.
The article outlines a comprehensive, bottom‑up learning path for containers, covering Linux container fundamentals, images, runtimes, managers, orchestrators, and non‑Linux implementations, while clarifying common misconceptions, explaining how runtimes like runc work, and comparing Docker, containerd, and Kubernetes.
This article explains the history and evolution of Docker and Containerd, compares their architectures and functions, and discusses how Containerd operates independently within cloud‑native environments such as Kubernetes.
This article walks you through configuring containerd image pull acceleration using crictl, ctr, and nerdctl, provides a curated list of accelerated registry mirrors, shows exact command‑line examples, and demonstrates how to verify that the acceleration is effective, helping you speed up container workflows.
This guide walks you through using nerdctl with containerd to package images, install required components, run containers, build images, and achieve Docker‑Compose‑like orchestration, providing step‑by‑step commands and tips for a smooth cloud‑native workflow.
This guide walks you through preparing your Linux server, downloading and installing Containerd with its dependencies, configuring system settings, setting up systemd services, verifying the installation, pulling images, and applying security and performance best practices for production environments.
This article explains containerd’s role in Docker, outlines its core responsibilities and design goals, shows how to install and configure it on Ubuntu, and provides a complete Go example that pulls a Redis image, creates a container, runs and cleans up the task.
This article introduces four leading open‑source container platforms—Docker, Podman, Containerd, and CRI‑O—detailing their core features, architecture, and use‑case advantages, helping readers understand each product’s strengths and suitability for modern cloud‑native and micro‑service deployments.
This article explains how Kubernetes assigns unique IP addresses to Pods using Flannel as the CNI network provider and Containerd as the container runtime, covering underlying concepts like Linux bridges, VXLAN encapsulation, node IPAM, and the interactions among kubelet, CRI, and CNI plugins.
This article explains the role of container runtimes, distinguishes low‑level, high‑level, and sandbox runtimes, and compares three major implementations—containerd, CRI‑O, and Docker—detailing their architecture, image handling, networking, storage, and integration with OCI specifications.
Kubernetes 1.24 officially deprecated Dockershim in favor of containerd, explaining the reasons, the underlying container runtime components, the changes in pod creation workflow, the impact on users and operators, and providing practical migration steps and best‑practice recommendations.
This article introduces several widely used container engines—including Docker, Podman, LXD, Containerd, and CRI‑O—explaining their core components, architectural differences, security features, and typical use cases for developers and operations teams.
When replacing dockershim with containerd, we observed that pods take over a minute to start because the GenericPLEG Relisting operation stalls for more than 30 seconds during node boot, caused by containerd’s UpdateContainerResources holding a bbolt lock and intensive image pulls; the article explains the root cause and provides a fix using the overlay volatile mount option.
This article explains the role of container runtimes, classifies them into low‑level, high‑level, and sandbox types, and details the architectures and key components of popular runtimes such as containerd, CRI‑O, and Docker, highlighting their interactions with OCI specifications and system resources.
The article explains how Koordinator and containerd integrate the Node Resource Interface (NRI) to improve container QoS, avoid noisy‑neighbor issues, and provide a flexible, standardized resource‑management model for cloud‑native workloads, as presented at KubeCon China 2023.
This article outlines the architecture and functions of container runtimes, detailing low‑level, high‑level, and sandbox types, and compares major implementations such as runC, containerd, CRI‑O, and Docker, highlighting their components, image handling, networking, storage, and integration with Kubernetes.
Docker version 24.0.6 introduces numerous bug fixes and feature enhancements—including fixes to containerd storage backend commands, overlayfs snapshotter issues, network isolation rules, and Windows service registration—alongside packaging updates such as upgrading Go to 1.20.7, containerd to v1.7.3, and Compose to v2.21.0.
Starting with Kubernetes v1.24 the built‑in dockershim is removed, requiring users to switch to a CRI‑compatible runtime such as containerd or CRI‑O—or install cri‑dockerd for Docker compatibility—while updating scripts, logs, and tooling, and using crictl or ctr for debugging and managing containers and pods.
After Kubernetes announced the deprecation of Docker in version 1.24, this article examines several Docker alternatives—containerd, Podman, LXC/LXD, rkt, OpenVZ, Singularity, and CRI‑O—detailing their core features and advantages over Docker for modern cloud‑native environments.
This article explains how containerd works as a high‑level container runtime and demonstrates practical usage of its three command‑line clients—ctr, nerdctl, and crictl—for pulling images, managing containers, debugging Kubernetes pods, and performing low‑level runtime operations.
Docker Hub announced that free organization accounts will lose access to private repositories after April 14 unless upgraded to a paid plan, prompting community backlash, outlining the continued availability of public images, and reviewing alternative container solutions such as Podman and Containerd.
This guide explains what containerd is, how to manage images and containers with its command‑line clients ctr, nerdctl, and crictl, and provides practical examples of pulling, running, inspecting, and cleaning up containers in a Linux environment.
The containerd project completed a comprehensive fuzzing audit that added 28 fuzzers, uncovered a critical OCI image import vulnerability (CVE‑2023‑25153), and demonstrated the robustness of its codebase while highlighting the importance of fuzz testing for cloud‑native runtime security.
Kuaishou's container cloud platform tackled the challenge of large‑scale, stable image distribution by integrating Dragonfly and its Nydus subproject, achieving over 70% bandwidth relief, 90% pull‑time reduction, and seamless migration to containerd, thereby supporting billions of monthly users with high efficiency.
This article examines popular Docker alternatives—including Podman, LXD, Containerd, Buildah, BuildKit, and Kaniko—detailing their architectures, key differences, security features, and use cases, helping developers choose the right container engine for their workloads.
This comprehensive tutorial walks through preparing the operating system, installing Docker and containerd, configuring yum repositories, initializing a multi‑master HA Kubernetes cluster with IPVS, deploying the Kubernetes dashboard, setting up NFS storage, installing an Ingress controller, and finally installing Harbor with Helm and a custom NFS provisioner, providing all necessary commands and configuration files.
While Docker remains popular, a growing ecosystem of container runtimes—such as Podman, LXD, containerd, Buildah, BuildKit, and Kaniko—offers distinct features, security models, and integration options that make them viable replacements for various development and deployment scenarios.
Docker has released a technical preview of Docker+Wasm, partnering with the Bytecode Alliance and WasmEdge to add a containerd shim that runs WebAssembly modules, providing faster startup, smaller binaries, and a new runtime flag, while offering example commands and download links for early adopters.
This comprehensive tutorial walks through preparing multiple Linux nodes, installing Docker and containerd, setting up kubeadm, kubelet and kubectl, initializing a HA Kubernetes control plane, configuring Flannel networking, deploying the Kubernetes dashboard, installing Nginx + Keepalived for load balancing, setting up NFS with rsync, provisioning storage via Helm, and finally installing a secure Harbor image registry, all with detailed commands and configuration snippets.
Docker unveils a technical preview of Docker+Wasm, integrating WebAssembly into its container engine via a new containerd shim, offering faster startup, smaller binaries, and a seamless workflow for building and running Wasm applications, while joining the Bytecode Alliance to advance WASI standards.
This article surveys seven Docker alternatives—Podman, LXD, Containerd, Buildah, BuildKit, Kaniko, and RunC—detailing their architectures, key features, security models, and how they differ from Docker for container creation, management, and orchestration.
This article explains why Docker containers often stop right after starting by examining the Linux PID 1 init process, the behavior of foreground versus daemonized commands in Dockerfiles, and how container runtimes like containerd‑shim and runc manage the container’s main process.
This step‑by‑step guide walks you through deploying a production‑grade Kubernetes environment, covering node preparation, Docker and containerd setup, kubeadm initialization, high‑availability configuration with Nginx and Keepalived, installing the dashboard, and setting up a private Harbor registry with NFS storage, all using cloud‑native best practices.
This guide explains how to install and use nerdctl—a Docker‑compatible CLI for containerd—including basic commands for running containers, managing images, retrieving logs, and building images with BuildKit, providing a complete workflow for container development and deployment.
This article explains the technical reasons behind Kubernetes' decision to deprecate Docker, covering the introduction of the CRI shim, the rise of containerd, the phased removal of dockershim, and why Docker remains relevant in the cloud‑native ecosystem.
This article provides an in‑depth overview of major Docker alternatives—including Podman, LXD, Containerd, Buildah, BuildKit, and Kaniko—detailing their architectures, key differences, security features, and use‑cases for container creation, management, and image building in modern cloud‑native environments.
This article examines seven Docker alternatives—Podman, LXD, containerd, Buildah, BuildKit, Kaniko, and RunC—detailing their architectures, key differences, security features, and use‑cases to help DevOps teams choose the right container runtime for their workloads.
This step‑by‑step guide shows how to prepare three CentOS 7 nodes, install containerd, configure system settings, deploy kubeadm/kubelet/kubectl, initialize a Kubernetes v1.22.1 control plane, add worker nodes, install the flannel CNI plugin, set up the Dashboard, and clean up the environment.
This guide explains how to switch a Kubernetes cluster’s container runtime from Docker to containerd, including node maintenance, configuration changes, restarting services, verifying the runtime, installing and using crictl for container management, and comparing CLI tools, with detailed command examples.
This article provides a comprehensive overview of Docker's evolution, its modern architecture involving containerd, runc, and CRI, explains how containers are created and managed, and offers step‑by‑step instructions for installing, configuring, and operating containerd with the ctr command‑line tool on Linux.
This guide walks you through replacing Docker with Containerd in Kubernetes, explains the crictl and ctr command‑line tools, shows how to configure Containerd, and demonstrates using nerdctl and BuildKit for image building, tagging, and pushing to Harbor.
This article explains the evolution and classification of container runtimes, detailing low‑level and high‑level implementations, demoing low‑level runtime setup with runc, and describing how Kubernetes CRI integrates with runtimes like containerd, Docker, and CRI‑O.
This tutorial walks through migrating a two‑node Kubernetes cluster (master and worker) from Docker to containerd on CentOS 7, covering environment setup, node draining, Docker removal, containerd installation and configuration, kubelet adjustments, uncordoning, and verification of the new container runtime.
This article explains the key components and standards of the container ecosystem—including Docker, containerd, CRI‑O, OCI and runc—detailing how they interact, the role of the Container Runtime Interface, and why Docker is only a small part of a broader, interoperable cloud‑native landscape.
This guide walks through a real‑world Docker exec failure, explains the relationship between kubelet, docker‑shim, containerd, and runc, shows step‑by‑step commands to isolate the faulty component, and reveals that a resource‑limit (pids) exhaustion in the container caused the runc exec error.
This article reviews seven Docker alternatives—Podman, LXD, containerd, Buildah, BuildKit, Kaniko, and RunC—detailing their architectures, key differences, security models, and typical use cases for developers and DevOps teams seeking flexible, daemon‑less or Kubernetes‑friendly container solutions.
This article explains the challenges of CRI integration with multiple container runtimes, introduces Containerd ShimV2 as a standardized interface, and provides step‑by‑step instructions for configuring Kata Containers as a Kubernetes runtime using RuntimeClass or untrusted_workload_runtime methods.
This article walks through the prerequisites, node‑maintenance strategy, and detailed commands needed to safely upgrade Docker to 20.10.11 and containerd to 1.4.12 on a Kubernetes cluster that runs an Envoy‑based API gateway, ensuring minimal disruption for over 5,000 pods.
This article introduces the main image-building solutions for containerd runtimes, covering Docker-outside-Docker, DinD sidecars, DaemonSet deployments, and daemon-less tools such as Kaniko and Jib, with detailed YAML examples and usage instructions for CI/CD pipelines.
This article introduces containerd, compares its features, architecture, data directories, logging, CNI integration, stream services, commands, and namespaces with Docker, and helps you decide which container runtime best fits your Kubernetes deployments.
CRI shim is a gRPC server that implements the Container Runtime Interface, enabling kubelet to manage pod and container lifecycles, network via CNI, and streaming APIs like Exec, Attach, and PortForward, with detailed explanations of RuntimeService, ImageService, and the CRI‑containerd architecture.
RunC, the OCI‑compliant low‑level container runtime originally derived from Docker’s libcontainer, works alongside high‑level runtimes like containerd and cri‑o, and this article explains its origins, lifecycle states, usage commands, and how it fits into the broader cloud‑native container ecosystem.
This article provides a broad, non‑technical overview of Docker’s evolution, the diverse container technologies that preceded it, key Docker concepts and components, the Moby project, and the rise of orchestration tools, illustrating how containers have become mainstream from 2013 to 2017.
While Docker introduced containers in 2013 and set early standards, the ecosystem has since diversified with technologies like cgroups, namespaces, OCI, CRI, and alternatives such as containerd, runc, Podman, LXC/LXD, offering varied approaches to secure, lightweight application deployment across cloud-native environments.
The article recounts a real‑world incident where a container engine restart broke a FIFO, causing a Java service to stop responding, and walks through the step‑by‑step debugging process, explains the underlying stdio forwarding mechanism in container runtimes, and shows how a simple flag change fixes the bug.
This article provides a detailed overview of Docker’s evolution, the role of containerd, runc, and CRI in modern container runtimes, explains how Docker delegates container lifecycle management to containerd‑shim, and offers step‑by‑step instructions for installing, configuring, and using containerd with its CLI tools on Linux.
This tutorial walks through preparing three CentOS 7.6 nodes, installing and configuring containerd, setting up kubeadm, kubelet, and kubectl, initializing a Kubernetes v1.22.1 control plane, adding worker nodes, deploying the Flannel CNI plugin, installing the Kubernetes Dashboard, and providing cleanup commands, all with detailed commands and configuration files.
This article introduces the main container image building methods for environments using containerd, covering Docker‑outside‑Docker, DinD sidecars, DaemonSet deployment, and daemon‑less tools such as Kaniko and Jib, with detailed YAML examples and usage notes.
This tutorial walks through preparing three CentOS 7.6 nodes, disabling firewalls and SELinux, configuring sysctl and ipvs, installing containerd and its dependencies, generating containerd and kubeadm configurations, initializing the control plane, adding worker nodes, deploying the Flannel CNI plugin and Kubernetes Dashboard, and finally cleaning up the cluster.
This article explains the evolution and inner workings of Kubernetes container runtimes, detailing the roles of CRI, OCI, Docker, containerd, CRI‑O, and strong‑isolation solutions like Kata, gVisor, and Firecracker, and why the default dockershim remains prevalent.
This guide explains how to safely switch a Kubernetes cluster's container runtime from Docker to containerd by putting nodes into maintenance mode, updating configuration files, restarting services, verifying the change, and then using crictl for efficient container and pod management, including command comparisons and log handling.
An in‑depth troubleshooting story reveals how a container engine restart broke the FIFO used for stdio forwarding, causing a Java app to hang; the fix was simply changing the FIFO open mode from O_WRONLY to O_RDWR, and the article explains the underlying container I/O architecture.
This article explains Kubernetes' deprecation of Docker, introduces containerd as a lightweight, industry‑standard runtime, and provides step‑by‑step instructions for installing, configuring, and operating containerd on Linux, including common CLI commands for managing images and containers.
A Kubernetes pod reported readiness probe warnings with an OCI runtime exec failure, which was traced through kubelet, Docker, dockershim, containerd, and runc, ultimately caused by a race condition with cpu‑manager updating the container state file, and resolved by disabling cpu‑manager or upgrading runc.
This tutorial walks through installing Containerd on CentOS, pulling and managing a BusyBox container, configuring a CNI bridge network, enabling network access for containers, sharing host directories and PID namespaces, and finally integrating Docker alongside Containerd for a complete container runtime setup.
Alibaba’s open‑source DADI project introduces the overlaybd image format, which uses block‑level on‑demand reads, iSCSI targets, and a ZFile compression scheme to cut container cold‑start times by up to five times, offering a scalable solution for cloud‑native workloads.
This article explains why the Kubernetes dockershim component is being phased out, compares Docker and containerd command usage, and provides a step‑by‑step guide to set up a Kubernetes 1.20.5 cluster with containerd as the container runtime, including network plugin installation.
This article explains what containerd is, compares it with Docker, describes Kubernetes' CRI support, and provides step‑by‑step commands for using containerd via crictl, showing that migrating from Docker to containerd is simple and resource‑efficient.
This article explains the evolution and inner workings of Kubernetes container runtimes, covering the classic Docker‑based flow, the roles of CRI, OCI, containerd, CRI‑O, and strong‑isolation solutions like Kata, gVisor, and Firecracker, while clarifying why the architecture became so layered.
Explore the evolution of Containerd from Docker’s early days, its architecture, installation on Ubuntu, configuration nuances, performance benchmarks, and practical usage with the ctr CLI, while also learning how it integrates with Kubernetes, Docker, and tools like Sealos for streamlined container management.
Kubernetes has officially deprecated Docker support by removing the dockershim bridge, explaining that Docker lacks native CRI compliance, and recommends migrating to CRI‑compatible runtimes such as containerd or CRI‑O while clarifying the differences between CRI and OCI runtimes.
Kubernetes has removed Docker support by deprecating the dockershim bridge, urging users to adopt CRI‑compatible runtimes such as containerd or CRI‑O, and explaining the differences between CRI and OCI runtimes, their security implications, and migration recommendations.
This guide walks through installing NVIDIA drivers, CUDA toolkit, nvidia-container-runtime, configuring Containerd, deploying the NVIDIA device plugin, and testing GPU access inside Kubernetes pods, providing a complete solution for GPU workloads on containerd‑based clusters.
Starting with version 1.20 Kubernetes deprecates Docker as a container runtime, but Docker images remain usable through CRI‑compatible runtimes like containerd or CRI‑O, so developers can keep building with Docker while clusters transition to supported runtimes with minimal disruption.
This article analyzes Docker's declining market share and provides a detailed comparison of alternative container runtimes—including rkt, Mesos, LXC, OpenVZ, and Containerd—highlighting their features, advantages, and limitations for various production scenarios.
This article explains the origins and design of Kubernetes' Container Runtime Interface (CRI), how it abstracts container runtimes, details its lifecycle and streaming operations, reviews major implementations like CRI‑containerd and CRI‑O, and introduces essential debugging tools.
This article explains how WebAssembly has evolved beyond browsers, describes the WASI standard and its ecosystem, compares WASM containers with traditional Docker containers, and provides step‑by‑step instructions for installing a containerd WASM shim, configuring RuntimeClass, and deploying WASM workloads in a Kubernetes cluster.
Many Docker beginners encounter containers that stop immediately after launch, often due to the CMD process exiting as PID 1; this article explains Linux PID 1 behavior, process tables, zombie and orphan processes, and how Docker’s namespace and runtime components like containerd‑shim and runc affect container lifecycles.
This article explains how Linux containers achieve lightweight virtualization through namespaces and cgroups for resource isolation, describes Docker image layering with overlayfs, and walks through container engine internals such as containerd, its shim architecture, and the start/exec workflows.
