Open-source alternatives to Cert Manager

This project is a command-line tool for managing public key infrastructure and digital identities. It provides a comprehensive suite for X.509 certificate lifecycle management, including the generation, signing, renewal, and revocation of certificates and signing requests. The tool distinguishes itself through specialized security capabilities such as binding cryptographic credentials to TPMs and HSMs for hardware-backed identity attestation. It also provides dedicated support for machine identity security, using short-lived SSH certificates and mTLS to secure non-human workloads. Broad capa

acme.sh is a shell-based certificate manager and ACME SSL certificate client. It automates the issuance, renewal, and installation of digital security certificates using a portable Unix shell script to remove dependencies on heavy runtime environments. The project specializes in automated domain ownership verification through a DNS challenge automator that integrates with provider APIs. It supports the generation of diverse certificate types, including wildcard certificates and issuance based on pre-existing certificate signing requests. The tool covers the full certificate lifecycle, includ

The Operator SDK is a framework for building, packaging, and managing custom controllers that extend the Kubernetes API. It serves as a toolset for defining new API types and implementing reconcile loops to automate the lifecycles of complex applications. The project provides specialized support for creating operators based on Helm charts or Ansible playbooks, allowing users to maintain a desired cluster state using existing automation tools. It includes a dedicated system for packaging controllers into standardized container image bundles for distribution via the Operator Lifecycle Manager.

Allinssl is a multi-platform certificate manager and ACME automator designed to handle the full lifecycle of security certificates. It provides a web-based management interface to orchestrate the issuance, renewal, and deployment of certificates across various servers and cloud environments. The system distinguishes itself through an orchestration engine that pushes certificates to diverse targets, including web application firewalls, server control panels, and remote hosts. It automates domain ownership verification using DNS challenges across multiple providers and employs an event-driven w

Higress is an AI API gateway and cloud-native traffic manager that functions as a Kubernetes ingress controller. It provides a centralized system for routing, securing, and optimizing traffic directed toward large language models, AI agents, and microservice architectures. The project distinguishes itself through deep AI orchestration, including the ability to host and manage Model Context Protocol servers that transform REST APIs into tools for AI agents. It features specialized AI infrastructure for model request proxying, protocol translation across multiple providers, and semantic-based c

Certd is a self-hosted platform that automates the full lifecycle of SSL certificates using the ACME protocol. It handles certificate application, renewal, and deployment across multiple domains through a pipeline-driven workflow engine, with DNS challenge orchestration and multi-cloud deployment capabilities. The platform distinguishes itself through its configurable pipeline system, which allows users to build multi-step workflows that can pass outputs between tasks, execute custom scripts, and handle errors. It supports multi-tenant access control with role-based permissions, encrypted cre

Sealed Secrets is a Kubernetes secret encryption tool and controller designed for GitOps security. It provides a mechanism to encrypt sensitive data into specialized resources that can be safely stored in public version control systems and decrypted only within a cluster. The system uses an asymmetric encryption manager to seal secrets with a public key, ensuring that only the corresponding private key held within the cluster can unseal them. It includes utilities for security key rotation, secret re-encryption, and offline private key recovery to maintain data access during disaster recovery

cert-manager is a Kubernetes TLS certificate manager and cluster add-on that automates the issuance and renewal of TLS certificates. It functions as a certificate lifecycle automator, managing certificates as native Kubernetes resources to secure internal and external network traffic. The project includes an ACME protocol client to automate certificate requests and validations from providers. It utilizes a controller to synchronize the desired state of certificates with responses from various certificate authorities. The system covers certificate provisioning from external issuers and vault

Kubebuilder is a framework and set of scaffolding tools used to build Kubernetes APIs and controllers. It functions as an operator framework that provides generators for custom resource definitions, admission webhooks, and RBAC manifests to extend cluster functionality. The project distinguishes itself through marker-based code generation, which parses source code comments to automatically produce Kubernetes manifests and boilerplate logic. It employs a hub-and-spoke versioning model to translate data between multiple API versions and uses a three-way merge strategy to automate project migrat

Automate SSL/TLS certificates on Windows with ease

This project is a service mesh platform designed to manage, secure, and observe service-to-service communication within Kubernetes clusters. It functions as a control plane that orchestrates transparent sidecar proxies, which intercept and manage network traffic to provide reliable connectivity for microservices. By automating the injection of these proxies, the platform ensures that infrastructure-level policies are applied consistently across all workloads without requiring manual configuration changes. The platform distinguishes itself through its focus on zero-trust security and cross-clu

The AWS Cloud Development Kit is an infrastructure-as-code framework that enables developers to define and provision cloud resources using familiar programming languages. By utilizing construct-based synthesis, it translates high-level, object-oriented code into declarative templates, allowing for the automated management of complex cloud environments through a centralized, code-driven control plane. The framework distinguishes itself through its ability to model infrastructure as a dependency-aware resource graph, ensuring that components are provisioned and updated in the correct order. It

This project is a Kubernetes ingress controller that manages external traffic by dynamically configuring the HAProxy load balancer. It functions as a bridge between cluster resources and the network data plane, translating high-level ingress definitions into active proxy configurations to route HTTP, TCP, and UDP traffic into containerized environments. The controller distinguishes itself through a decoupled architecture that separates control plane logic from the proxy process, allowing for independent lifecycle management and versioning. It utilizes template-based configuration generation a

Certmagic is a Go library for automating the issuance and renewal of TLS certificates. It functions as an automatic HTTPS provisioner and ACME client that handles the full lifecycle of certificates to ensure secure connectivity without manual intervention. The library is distinguished by its support for on-demand TLS provisioning, which generates certificates dynamically during the TLS handshake based on the server name. It also provides automation for wildcard certificates through DNS challenge verification and integrates with the ZeroSSL API for certificate acquisition. The project covers

The AWS Load Balancer Controller is a Kubernetes controller that automates the provisioning and lifecycle management of cloud-native load balancing resources. It functions as an infrastructure orchestrator, translating declarative cluster configurations into specific requests for external cloud services to route traffic into containerized workloads. By implementing standard ingress and gateway specifications, the system ensures that cluster networking adheres to official industry standards for HTTP, HTTPS, and transport-layer traffic. The controller distinguishes itself through its deep integ

This project is an API gateway and ingress controller designed to manage traffic, security, and service connectivity within Kubernetes environments. It operates as a controller that monitors cluster state to reconcile gateway configurations with desired infrastructure definitions, ensuring that network policies and routing rules remain consistent across distributed deployments. The system distinguishes itself through a modular request pipeline that allows for the injection of custom logic to handle transformations, security checks, and logging. It supports declarative infrastructure managemen

This project is a toolkit for creating and managing X.509 certificate authorities, providing tools for the issuance, signing, and management of TLS certificates and private keys. It includes a command-line utility for generating certificate signing requests, bundling certificate chains, and parsing PEM or DER files. The system features an HTTP API server that allows for remote signing and verification of certificates using JSON requests and responses. This architecture supports automated certificate provisioning and includes a signing proxy to forward requests to remote backend services. The

The Prometheus Operator is a Kubernetes monitoring orchestrator and controller that manages Prometheus clusters and observability components through declarative custom resources. It functions as a custom resource controller that translates high-level Kubernetes resource definitions into the configuration files required by the underlying monitoring software. The project automates the deployment, scaling, and lifecycle of an observability stack, including the integration of components like Thanos and Alertmanager. It distinguishes itself by syncing monitoring targets, alerting rules, and scrape

This project is a comprehensive educational curriculum designed to teach the fundamentals of container orchestration and infrastructure automation. It provides a structured learning path for mastering the lifecycle management of containerized applications, covering the core concepts of declarative resource definitions, control-loop-based reconciliation, and distributed cluster state management. The course distinguishes itself by focusing on practical, hands-on implementation of modern DevOps practices. It guides users through the integration of GitOps workflows for state synchronization, the

Mitmproxy is an interactive, programmable network proxy engine designed for traffic analysis and protocol manipulation. It functions as a gateway that intercepts, inspects, and modifies network traffic in real-time, supporting HTTP, HTTPS, WebSocket, DNS, and generic TCP or UDP streams. By acting as a trusted certificate authority, the proxy can dynamically generate and sign certificates to decrypt and analyze secure TLS-encrypted connections. The project distinguishes itself through a highly extensible, event-driven architecture that allows users to automate traffic transformation using cust

HAProxy is a high-performance TCP and HTTP proxy that distributes traffic across multiple backend servers to ensure availability and fault tolerance for critical services. It operates in either TCP or HTTP mode, with an event-driven, single-threaded reactor that handles tens of thousands of connections without context switching, and supports kernel-level data transfer to minimize memory usage and latency. What distinguishes HAProxy is its configuration-file-first design, where all load-balancing rules and runtime behavior are defined in a declarative text file parsed at startup. It embeds a L

Nebula is a scalable, decentralized overlay networking tool designed to create secure, encrypted peer-to-peer connections between distributed hosts. By utilizing a certificate-based identity authority, it enables the construction of private communication fabrics across disparate physical infrastructures, such as multiple cloud providers or on-premises data centers, without requiring central authentication servers. The project distinguishes itself through a zero-trust architecture that enforces granular, policy-driven firewall filtering based on certificate-derived group memberships. It facili

This project provides a comprehensive guide and set of scripts for deploying and configuring a production-ready Kubernetes cluster from scratch. It centers on establishing a functional environment by installing core management components, storage, and networking across multiple nodes. The implementation emphasizes high availability for the control plane, utilizing layer-4 load balancing and leader election for the API server, scheduler, and controller manager. It further ensures reliability through the deployment of a distributed key-value store for persistent runtime data. The project cover

kops is a Kubernetes cluster provisioner and lifecycle manager designed to automate the creation, maintenance, and destruction of production-grade clusters on cloud infrastructure. It functions as a declarative infrastructure manager, synchronizing the live state of a cluster with versioned manifests stored in remote object storage to ensure idempotent operations. The project distinguishes itself by offering comprehensive automation for the entire cluster lifecycle, including high-availability control plane deployment, incremental rolling updates, and automated version upgrades. It also serve

The NGINX Ingress Controller is a Kubernetes-native traffic manager that handles external requests and routes them to internal services. It translates Kubernetes API objects and annotations into proxy configurations to manage incoming HTTP, TCP, and UDP traffic. The controller distinguishes itself through advanced traffic steering and security integration. It supports blue-green and canary traffic splitting, as well as content-based and regex path routing. Security is handled at the edge via a web application firewall, denial-of-service protection, and a variety of authentication methods incl

This project is a high-performance, distributed API gateway designed to manage, secure, and observe traffic for microservices, serverless functions, and artificial intelligence model providers. It functions as a dynamic service proxy and cloud-native ingress controller, centralizing policy enforcement and traffic routing through a unified configuration interface that synchronizes state across multiple nodes in real time. The platform distinguishes itself through a highly extensible architecture that utilizes a high-performance scripting engine to execute modular logic directly within the requ

Octelium is a zero-trust network access platform and identity-aware proxy designed to secure private HTTP, SSH, and SQL resources. It functions as a secure gateway that validates human and workload identities using OIDC, SAML, and FIDO2 passkeys before granting access to internal applications and SaaS APIs. The system is distinguished by its secretless access broker, which injects credentials—such as API keys, passwords, and AWS Sigv4 signatures—at the gateway level so users can access databases and cloud resources without managing secrets. It further specializes in AI gateway administration,