Azure Linux: Driving Security in the Era of AI Innovation
Microsoft is advancing cloud and AI innovation with a clear focus on security, quality, and responsible practices. At Ignite 2025, Azure Linux reflects that commitment. As Microsoft’s ubiquitous Linux OS, it powers critical services and serves as the hub for security innovation. This year’s announcements, Azure Linux with OS Guard public preview and GA of pod sandboxing, reinforce security as one of our core priorities, helping customers build and run workloads with confidence in an increasingly complex threat landscape. Announcing OS Guard Public Preview We’re excited to announce the public preview of Azure Linux with OS Guard at Ignite 2025! OS Guard delivers a hardened, immutable container host built on the FedRAMP-certified Azure Linux base image. It introduces a significantly streamlined footprint with approximately 100 fewer packages than the standard Azure Linux image, reducing the attack surface and improving performance. FIPS mode is enforced by default, ensuring compliance for regulated workloads right out of the box. Additional security features include dm-verity for filesystem immutability, Trusted Launch backed by vTPM-secured keys, and seamless integration with AKS for container workloads. Built with upstream transparency and active Microsoft contributions, OS Guard provides a secure foundation for containerized applications while maintaining operational simplicity. During the preview period, code integrity and mandatory access Control (SELinux) are enabled in audit mode, allowing customers to validate policies and prepare for enforcement without impacting workloads. General Availability: Pod Sandboxing for stronger isolation on AKS We’re also announcing the GA of pod sandboxing on AKS, delivering stronger workload isolation for multi-tenant and regulated environments. Based on the open source Kata project, Pod Sandboxing introduces VM-level isolation for containerized workloads by running each pod inside its own lightweight virtual machine using Kata Containers, providing a stronger security boundary compared to traditional containers. Connect with us at Ignite Meet the Azure Linux team and see these innovations in action: Ignite: Join us at our breakout session (https://ignite.microsoft.com/en-US/sessions/BRK144) and visit the Linux on Azure Booth for live demos and deep dives. Session Type Session Code Session Name Date/Time (PST) Breakout BRK 143 Optimizing performance, deployments, and security for Linux on Azure Thu, Nov 20/ 1:00 PM – 1:45 PM Breakout BRK 144 Build, modernize, and secure AKS workloads with Azure Linux Wed, Nov 19/ 1:30 PM – 2:15 PM Breakout BRK 104 From VMs and containers to AI apps with Azure Red Hat OpenShift Thu, Nov 20/ 8:30 AM – 9:15 AM Theatre TRH 712 Hybrid workload compliance from policy to practice on Azure Tue, Nov 18/ 3:15 PM – 3:45 PM Theatre THR 701 From Container to Node: Building Minimal-CVE Solutions with Azure Linux Wed, Nov 19/ 3:30 PM – 4:00 PM Lab Lab 505 Fast track your Linux and PostgreSQL migration with Azure Migrate Tue, Nov 18/ 4:30 PM – 5:45 PM PST Wed, Nov 19/ 3:45 PM – 5:00 PM PST Thu, Nov 20/ 9:00 AM – 10:15 AM PST Whether you’re migrating workloads, exploring security features, or looking to engage with our engineering team, we’re eager to connect and help you succeed with Azure Linux. Resources to get started Azure Linux OS Guard Overview & QuickStart: https://aka.ms/osguard Pod Sandboxing Overview & QuickStart: https://aka.ms/podsandboxing Azure Linux Documentation: https://learn.microsoft.com/en-us/azure/azure-linux/From Policy to Practice: Built-In CIS Benchmarks on Azure - Flexible, Hybrid-Ready
Security is more important than ever. The industry-standard for secure machine configuration is the Center for Internet Security (CIS) Benchmarks. These benchmarks provide consensus-based prescriptive guidance to help organizations harden diverse systems, reduce risk, and streamline compliance with major regulatory frameworks and industry standards like NIST, HIPAA, and PCI DSS. In our previous post, we outlined our plans to improve the Linux server compliance and hardening experience on Azure and shared a vision for integrating CIS Benchmarks. Today, that vision has turned into reality. We're now announcing the next phase of this work: Center for Internet Security (CIS) Benchmarks are now available on Azure for all Azure endorsed distros, at no additional cost to Azure and Azure Arc customers. With today's announcement, you get access to the CIS Benchmarks on Azure with full parity to what’s published by the Center for Internet Security (CIS). You can adjust parameters or define exceptions, tailoring security to your needs and applying consistent controls across cloud, hybrid, and on-premises environments - without having to implement every control manually. Thanks to this flexible architecture, you can truly manage compliance as code. How we achieve parity To ensure accuracy and trust, we rely on and ingest CIS machine-readable Benchmark content (OVAL/XCCDF files) as the source of truth. This guarantees that the controls and rules you apply in Azure match the official CIS specifications, reducing drift and ensuring compliance confidence. What’s new under the hood At the core of this update is azure-osconfig’s new compliance engine - a lightweight, open-source module developed by the Azure Core Linux team. It evaluates Linux systems directly against industry-standard benchmarks like CIS, supporting both audit and, in the future, auto-remediation. This enables accurate, scalable compliance checks across large Linux fleets. Here you can read more about azure-osconfig. Dynamic rule evaluation The new compliance engine supports simple fact-checking operations, evaluation of logic operations on them (e.g., anyOf, allOf) and Lua based scripting, which allows to express complex checks required by the CIS Critical Security Controls - all evaluated natively without external scripts. Scalable architecture for large fleets When the assignment is created, the Azure control plane instructs the machine to pull the latest Policy package via the Machine Configuration agent. Azure-osconfig’s compliance engine is integrated as a light-weight library to the package and called by Machine Configuration agent for evaluation – which happens every 15-30minutes. This ensures near real-time compliance state without overwhelming resources and enables consistent evaluation across thousands of VMs and Azure Arc-enabled servers. Future-ready for remediation and enforcement While the Public Preview starts with audit-only mode, the roadmap includes per-rule remediation and enforcement using technologies like eBPF for kernel-level controls. This will allow proactive prevention of configuration drift and runtime hardening at scale. Please reach out if you interested in auto-remediation or enforcement. Extensibility beyond CIS Benchmarks The architecture was designed to support other security and compliance standards as well and isn’t limited to CIS Benchmarks. The compliance engine is modular, and we plan to extend the platform with STIG and other relevant industry benchmarks. This positions Azure as a platform for a place where you can manage your compliance from a single control-plane without duplicating efforts elsewhere. Collaboration with the CIS This milestone reflects a close collaboration between Microsoft and the CIS to bring industry-standard security guidance into Azure as a built-in capability. Our shared goal is to make cloud-native compliance practical and consistent, while giving customers the flexibility to meet their unique requirements. We are committed to continuously supporting new Benchmark releases, expanding coverage with new distributions and easing adoption through built-in workflows, such as moving from your current Benchmark version to a new version while preserving your custom configurations. Certification and trust We can proudly announce that azure-osconfig has met all the requirements and is officially certified by the CIS for Benchmark assessment, so you can trust compliance results as authoritative. Minor benchmark updates will be applied automatically, while major version will be released separately. We will include workflows to help migrate customizations seamlessly across versions. Key Highlights Built-in CIS Benchmarks for Azure Endorsed Linux distributions Full parity with official CIS Benchmarks content and certified by the CIS for Benchmark Assessment Flexible configuration: adjust parameters, define exceptions, tune severity Hybrid support: enforce the same baseline across Azure, on-prem, and multi-cloud with Azure Arc Reporting format in CIS tooling style Supported use cases Certified CIS Benchmarks for all Azure Endorsed Distros - Audit only (L1/L2 server profiles) Hybrid / On-premises and other cloud machines with Azure Arc for the supported distros Compliance as Code (example via Github -> Azure OIDC auth and API integration) Compatible with GuestConfig workbook What’s next? Our next mission is to bring the previously announced auto-remediation capability into this experience, expand the distribution coverage and elevate our workflows even further. We’re focused on empowering you to resolve issues while honoring the unique operational complexity of your environments. Stay tuned! Get Started Documentation link for this capability Enable CIS Benchmarks in Machine Configuration and select the “Official Center for Internet Security (CIS) Benchmarks for Linux Workloads” then select the distributions for your assignment, and customize as needed. In case if you want any additional distribution supported or have any feedback for azure-osconfig – please open an Azure support case or a Github issue here Relevant Ignite 2025 session: Hybrid workload compliance from policy to practice on Azure Connect with us at Ignite Meet the Linux team and stop by the Linux on Azure booth to see these innovations in action: Session Type Session Code Session Name Date/Time (PST) Theatre THR 712 Hybrid workload compliance from policy to practice on Azure Tue, Nov 18/ 3:15 PM – 3:45 PM Breakout BRK 143 Optimizing performance, deployments, and security for Linux on Azure Thu, Nov 20/ 1:00 PM – 1:45 PM Breakout BRK 144 Build, modernize, and secure AKS workloads with Azure Linux Wed, Nov 19/ 1:30 PM – 2:15 PM Breakout BRK 104 From VMs and containers to AI apps with Azure Red Hat OpenShift Thu, Nov 20/ 8:30 AM – 9:15 AM Theatre THR 701 From Container to Node: Building Minimal-CVE Solutions with Azure Linux Wed, Nov 19/ 3:30 PM – 4:00 PM Lab Lab 505 Fast track your Linux and PostgreSQL migration with Azure Migrate Tue, Nov 18/ 4:30 PM – 5:45 PM PST Wed, Nov 19/ 3:45 PM – 5:00 PM PST Thu, Nov 20/ 9:00 AM – 10:15 AM PSTInnovations and Strengthening Platforms Reliability Through Open Source
The Linux Systems Group (LSG) at Microsoft is the team building OS innovations in Azure enabling secure and high-performance platforms that power millions of workloads worldwide. From providing the OS for Boost, optimizing Linux kernels for hyperscale environments or contributing to open-source projects like Rust-VMM and Cloud Hypervisor, LSG ensures customers get the best of Linux on Azure. Our work spans performance tuning, security hardening, and feature enablement for new silicon enablement and cutting-edge technologies, such as Confidential Computing, ARM64 and Nvidia Grace Blackwell all while strengthening the global open-source ecosystem. Our philosophy is simple: we develop in the open and upstream first, integrating improvements into our products after they’ve been accepted by the community. At Ignite we like to highlight a few open-source key contributions in 2025 that are the foundations for many product offerings and innovations you will see during the whole week. We helped bring seamless kernel update features (Kexec HandOver) to the Linux kernel, improved networking paths for AI platforms, strengthened container orchestration and security efforts, and shared engineering insights with global communities and conferences. This work reflects Microsoft’s long-standing commitment to open source, grounded in active upstream participation and close collaboration with partners across the ecosystem. Our engineers work side-by-side with maintainers, Linux distro partners, and silicon providers to ensure contributions land where they help the most, from kernel updates to improvements that support new silicon platforms. Linux Kernel Contributions Enabling Seamless Kernel Updates: Persistent uptime for critical services is a top priority. This year, Microsoft engineer Mike Rapoport successfully merged Kexec HandOver (KHO) into Linux 6.16 1 . KHO is a kernel mechanism that preserves memory state across a reboot (kexec), allowing systems to carry over important data when loading a new kernel. In practice, this means Microsoft can apply security patches or kernel updates to Azure platform and customers VMs without rebooting or with significantly reduced downtime. It’s a technical achievement with real impact: cloud providers and enterprises can update Linux on the fly, enhancing security and reliability for services that demand continuous availability. Optimizing Network Drivers for AI Scale: Massive AI models require massive bandwidth. Working closely with our partners deploying large AI workloads on Azure, LSG engineers delivered a breakthrough in Linux networking performance. LSG team rearchitected the receive path of the MANA network driver (used by our smart NICs) to eliminate wasted memory and enable recycling of buffers. 2x higher effective network throughput on 64 KB page systems 35% better memory efficiency for RX buffers 15% higher throughput and roughly half the memory use even on standard x86_64 VMs References MANA RX optimization patch: net: mana: Use page pool fragments for RX buffers LKML Linux Plumbers 2025 talk: Optimizing traffic receive (RX) path in Linux kernel MANA Driver for larger PAGE_SIZE systems Improving Reliability for Cloud Networking: In addition to raw performance, reliability got a boost. One critical fix addressed a race condition in the Hyper-V hv_netvsc driver that sometimes caused packet loss when a VM’s network channel initialized. By patching this upstream, we improved network stability for all Linux guests running on Hyper-V keeping customer VMs running smoothly during dynamic operations like scale-out or live migrations. Our engineers also upstreamed numerous improvements to Hyper-V device drivers (covering storage, memory, and general virtualization).We fixed interrupt handling bugs, eliminated outdated patches, and resolved issues affecting ARM64 architectures. Each of these fixes was contributed to the mainline kernel, ensuring that any Linux distribution running on Hyper-V or Azure benefits from the enhanced stability and performance. References Upstream fix: hv_netvsc race on early receive events: kernel.org commit referenced by Ubuntu bug Launchpad Ubuntu Azure backport write-up: Bug 2127705 – hv_netvsc: fix loss of early receive events from host during channel open Launchpad Older background on hv_netvsc packet-loss issues: kernel.org bug 81061 Strengthening Core Linux Infrastructure: Several of our contributions targeted fundamental kernel subsystems that all Linux users rely on. For example, we led significant enhancements to the Virtual File System (VFS) layer reworking how Linux handles process core dumps and expanding file management capabilities. These changes improve how Linux handles files and memory under the hood, benefiting scenarios from large-scale cloud storage to local development. We also continued upstream efforts to support advanced virtualization features.Our team is actively upstreaming the mshv_vtl driver (for managing secure partitions on Hyper-V) and improving Linux’s compatibility with nested virtualization on Azure’s Microsoft Hypervisor (MSHV). All this low-level work adds up to a more robust and feature-rich kernel for everyone. References Example VFS coredump work: split file coredumping into coredump_file() mshv_vtl driver patchset: Drivers: hv: Introduce new driver – mshv_vtl (v10) and v12 patch series on patchew Bolstering Linux Security in the Cloud: Security has been a major thread across our upstream contributions. One focus area is making container workloads easier to verify and control. Microsoft engineers proposed an approach for code integrity in containers built on containerd’s EROFS snapshotter, shared as an open RFC in the containerd project -GitHub. The idea is to use read-only images plus integrity metadata so that container file systems can be measured and checked against policy before they run. We also engaged deeply with industry partners on kernel vulnerability handling. Through the Cloud-LTS Linux CVE workgroup, cloud providers and vendors collaborate in the open on a shared analysis of Linux CVEs. The group maintains a public repository that records how each CVE affects various kernels and configurations, which helps reduce duplicated triage work and speeds up security responses. On the platform side, our engineers contributed fixes to the OP-TEE secure OS used in trusted execution and secure-boot scenarios, making sure that the cryptographic primitives required by Azure’s Linux boot flows behave correctly across supported devices. These changes help ensure that Linux verified boot chains remain reliable on Azure hardware. References containerd RFC: Code Integrity for OCI/containerd Containers using erofs-snapshotter GitHub Cloud-LTS public CVE analysis repo: cloud-lts/linux-cve-analysis Linux CVE workgroup session at Linux Plumbers 2025: Linux CVE workgroup OP-TEE project docs: OP-TEE documentation Developer Tools & Experience Smoother OS Management with Systemd: Ensuring Linux works seamlessly on Azure scale. The core init system systemd saw important improvements from our team this year. LSG contributed and merged upstream support for disk quota controls in systemd services. With new directives (like StateDirectoryQuota and CacheDirectoryQuota), administrators can easily enforce storage limits for service data, which is especially useful in scenarios like IoT devices with eMMC storage on Azure’s custom SoCs. In addition, Sea-Team added an auto-reload feature to systemd-journald, allowing log configuration changes to apply at runtime without restarting the logging service . These improvements, now part of upstream systemd, help Azure and other Linux environments perform updates or maintenance with minimal disruption to running services. These improvements help Azure and other environments roll out configuration updates with less impact on running workloads. References systemd quota directives: systemd.exec(5) – StateDirectoryQuota and related options systemd journald reload behavior: systemd-journald.service(8) Empowering Linux Quality at Scale: Running Linux on Azure at global scale requires extensive, repeatable testing. Microsoft continues to invest in LISA (Linux Integration Services Automation), an open-source framework that validates Linux kernels and distributions on Azure and other Hyper-V–based environments. Over the past year we expanded LISA with: New stress tests for rapid reboot sequences to catch elusive timing bugs Better failure diagnostics to make complex issues easier to root-cause Extended coverage for ARM64 scenarios and technologies like InfiniBand networking Integration of Azure VM SKU metadata and policy checks so that image validation can automatically confirm conformance to Azure requirements These changes help us qualify new kernels, distributions, and VM SKUs before they are shipped to customers. Because LISA is open source, partners and Linux vendors can run the same tests and share results, which raises quality across the ecosystem. References LISA GitHub repo: microsoft/lisa LISA documentation: Welcome to Linux Integration Services Automation LISA Documentation Community Engagement and Leadership Sharing Knowledge Globally: Open-source contribution is not just about code - it’s about people and knowledge exchange. Our team members took active roles in community events worldwide, reflecting Microsoft’s growing leadership in the Linux community. We were proud to be a Platinum Sponsor of the inaugural Open Source Summit India 2025 in Hyderabad, where LSG engineers served on the program committee and hosted technical sessions. At Linux Security Summit Europe 2025, Microsoft’s security experts shaped the agenda as program committee members, delivered talks (such as “The State of SELinux”), and even led panel discussions alongside colleagues from Intel, Arm, and others. And in Paris at Kernel Recipes 2025, our own SMEs shared kernel insights with fellow developers. By engaging in these events, Microsoft not only contributes code but also helps guide the conversation on the future of Linux. These relationships and public interactions build mutual trust and ensure that we remain closely aligned with community priorities. References Event: Open Source Summit India 2025 – Linux Foundation Paul Moore’s talk archive: LSS-EU 2025 Conference: Kernel Recipes 2025 and Kernel Recipes 2025 schedule Closing Thoughts Microsoft’s long-term commitment to open source remains strong, and the Linux Systems Group will continue contributing upstream, collaborating across the industry, and supporting the upstream communities that shape the technologies we rely on. Our work begins in upstream projects such as the Linux kernel, Kubernetes, and systemd, where improvements are shared openly before they reach Azure. The progress highlighted in this blog was made possible by the wider Linux community whose feedback, reviews, and shared ideas help refine every contribution. As we move ahead, we welcome maintainers, developers, and enterprise teams to engage with our projects, offer input, and collaborate with us. We will continue contributing code, sharing knowledge, and supporting the open-source technologies that power modern computing, working with the community to strengthen the foundation and shape a future that benefits everyone. References & Resources: Microsoft’s Open-Source Journey – Azure Blog https://techcommunity.microsoft.com/t5/linux-and-open-source-blog/linux-and-open-source-on-azure-quarterly-update-february-2025/ba-p/4382722 Cloud Hypervisor Project Rust-VMM Community Microsoft LISA (Linux Integration Services Automation) Repository Cloud-LTS Linux CVE Analysis ProjectLinux on Azure at Microsoft Ignite 2025: What’s New, What to Attend, and Where to Find Us
Microsoft Ignite 2025 is almost here, and we’re heading back to San Francisco from November 17-21 with a full digital experience for those joining online. Every year, Ignite brings together IT pros, developers, security teams, and technology leaders from around the world to explore the future of cloud, AI, and infrastructure. This year, Linux takes center stage in a big way. From new security innovations in Azure Linux to deeper AKS modernization capabilities and hands-on learning opportunities, Ignite 2025 is packed with content for anyone building, running, or securing Linux-based workloads in Azure. Below is your quick guide to the biggest Linux announcements and the must-see sessions. Major Linux Announcements at Ignite 2025 Public Preview: Built-in CIS Benchmarks for Azure Endorsed Linux Distributions CIS Benchmarks are now integrated directly into Azure Machine Configuration, giving you automated and customizable compliance monitoring across Azure, hybrid, and on-prem environments. This makes it easier to continuously govern your Linux estate at scale with no external tooling required. Public Preview: Azure Linux OS Guard Azure Linux OS Guard introduces a hardened, immutable Linux container host for AKS with FIPS mode enforced by default, a reduced attack surface, and tight AKS integration. It is ideal for highly regulated or sensitive workloads and brings stronger default security with less operational complexity. General Availability: Pod Sandboxing for AKS (Kata Containers) Pod Sandboxing with fully managed Kata Containers is now GA, delivering VM-level isolation for AKS workloads. This provides stronger separation of CPU, memory, and networking and is well-suited for multi-tenant applications or organizations with strict compliance boundaries. Linux Sessions at Ignite Whether you are optimizing performance, modernizing with containers, or exploring new security scenarios, there is something for every Linux practitioner. Breakout Sessions Session Code Session Name Date and Time (PST) BRK143 Optimizing performance, deployments, and security for Linux on Azure Thu Nov 20, 1:00 PM to 1:45 PM BRK144 Build, modernize, and secure AKS workloads with Azure Linux Wed Nov 19, 1:30 PM to 2:15 PM BRK104 From VMs and containers to AI apps with Azure Red Hat OpenShift Thu Nov 20, 8:30 AM to 9:15 AM BRK137 Nasdaq Boardvantage: AI-driven governance on PostgreSQL and AI Foundry Wed Nov 19, 11:30 AM to 12:15 PM Theatre Sessions Session Code Session Name Date and Time (PST) THR712 Hybrid workload compliance from policy to practice on Azure Tue Nov 18, 3:15 PM to 3:45 PM THR701 From Container to Node: Building Minimal-CVE Solutions with Azure Linux Wed Nov 19, 3:30 PM to 4:00 PM Hands-on Lab Lab 505: Fast track your Linux and PostgreSQL migration with Azure Migrate Tue Nov 18, 4:30 PM to 5:45 PM Wed Nov 19, 3:45 PM to 5:00 PM Thu Nov 20, 9:00 AM to 10:15 AM This interactive lab helps you assess, plan, and execute Linux and PostgreSQL migrations at scale using Azure Migrate’s end-to-end tooling. Meet the Linux on Azure Team at Ignite If you are attending in person, come say hello. Visit the Linux on Azure Expert Meetup stations inside the Microsoft Hub. You can ask questions directly to Microsoft’s Linux engineering and product experts, explore demos across Azure Linux, compliance, and migration, and get recommendations tailored to your workloads. We always love meeting customers and partners.Dalec: Declarative Package and Container Builds
Build once, deploy everywhere. From a single YAML specification, Dalec produces native Linux packages (RPM, DEB) and container images - no Dockerfiles, no complex RPM spec or control files, just declarative configuration. Dalec, a Cloud Native Computing Foundation (CNCF) Sandbox project, is a Docker BuildKit frontend that enables users to build system packages and container images from declarative YAML specifications. As a BuildKit frontend, Dalec integrates directly into the Docker build process, requiring no additional tools beyond Docker itself.Introducing Image Customizer for Azure Linux
We are excited to release Image Customizer, an open-source tool, built and maintained by the Azure Linux team. Image Customizer lets you customize well-tested existing Azure Linux images for any scenario in just minutes. Already trusted by first party teams like LinkedIn, Azure Frontdoor, and Azure Nexus in production, this tool is designed to make image customization simple, reliable, and fast. With full dm-verity support for enhanced security, it also supports customization of Azure Linux with OS Guard images. Unlike VM-based image customization, Image Customizer directly modifies the image without booting a VM using a chroot-based approach, making customization faster, more reliable, and easier to integrate into existing workflows. ✨ Get Image Customizer here ✨ Explore our documentation here. Why Choose Image Customizer? Direct, Reliable Customization Build on top of bootable, tested, and supported base images. Lower overhead and fewer side effects by avoiding VM boot. No need to rely on the Azure Linux Toolkit. Previously, building from scratch meant your image may fail to boot sometimes. Image Customizer reduces that risk. Clean and Lightweight Minimal dependencies for a streamlined setup (for example, no SSH required). You only need to invoke one command to run Image Customizer. It is available as a container with all its dependencies bundled for easy integration into CI/CD pipelines. Versatile and Powerful Supported input formats: vhd, vhdx, qcow2, PXE bootable artifacts, raw and iso created by Image Customizer. Supported output formats: vhd, vhd-fixed, vhdx, qcow2, raw, iso, and cosi. Perform a wide range of operations: add/remove/update packages, add files and directories, create/update users, enable/disable services, customize partitions, image history, dm-verity and more. Full list of supported operations can be found here. Cross-Platform Compatibility Tested and verified to work on Ubuntu 22.04, Azure Linux 3.0 and WSL2 (Windows Subsystem for Linux). While officially tested on these platforms, Image Customizer will likely work on other Linux distributions as well. Consistent and Predictable Builds Use --package-snapshot-time or snapshotTime to filter packages by publication timestamp, ensuring only packages available at that point in time are considered. This prevents unexpected changes from newer package versions when reusing configuration files across time. Getting Started with Image Customizer To use Image Customizer, you’ll need a configuration file that describes the changes you want to make, using the Declarative API provided by Image Customizer. Next, select a base Azure Linux image as your foundation. With these two pieces in hand, you’re ready to run Image Customizer. The easiest way is to use the Image Customizer container, which comes pre-packaged with all necessary dependencies and is recommended for most users. Alternatively, you can use the standalone executable binary if that better fits your workflow. In just a few minutes, Image Customizer will generate a modified Azure Linux image tailored to your needs. This process is designed to be repeatable and user-friendly, making it easy to add packages, files, users, make partition changes, and much more. To help you get started, we have a Quick Start guide that walks you through your first customization step by step. For those who want to explore further, comprehensive API documentation is available, covering both Command-line usage and Configuration options. Upcoming Community Call Join our upcoming community call to learn more about using Image Customizer and see a live demo. We’ll cover best practices, advanced scenarios, and answer any questions you may have. Date & Time: September 25 th , 2025 at 8:00AM PST Teams Link: Azure Linux - External Community Call | Meeting-Join | Microsoft Teams Community Call Schedule: https://learn.microsoft.com/en-us/azure/azure-linux/support-help#stay-connected-with-azure-linux Help and Feedback If you’d like to report bugs, request features, or contribute to the tool, you can do so directly through our azure-linux-image-tools GitHub repo. We welcome feedback and contributions from the community! Acknowledgements A huge thank you (in no order) to our Image Customizer team ─ Adit Jha, Brian Telfer, Chris Gunn, Deepu Thomas, Elaine Zhao, George Mileka, Himaja Kesari, Jim Perrin, Jiri Appl, Lanze Liu, Roaa Sakr, Kavya Nagalakunta and Vince Perri.
Red Hat Enterprise Linux Billing Meter ID Updates on Azure
Background Following Red Hat's transition to a scalable vCPU-based pricing model in early 2024, Microsoft Azure implemented corresponding pricing updates for RHEL services. As part of ensuring our billing infrastructure fully supports this new pricing structure, we are updating the billing meter IDs for Red Hat Enterprise Linux services to provide better alignment with the current pricing model. What's Changing As part of optimizing our billing infrastructure to fully support Red Hat's updated pricing model, Microsoft Azure is updating the billing meter IDs for Red Hat Enterprise Linux (RHEL) services. These changes ensure our billing system properly accommodates the vCPU-based pricing structure and Reserved Instance functionality. Effective Date: The meter ID migration will begin rolling out on October 2-8, 2025. Impact on Customers Pay-As-You-Go (PAYG) Customers Billing Continuity: Your RHEL instances will continue to operate without any service interruption Meter ID Changes: New meter IDs will appear in your usage reports and cost management statements starting Oct 2-8, 2025 Usage Tracking: Historical usage data remains accessible through existing billing reports Important: No Pricing Impact This meter ID migration has no impact on pricing. Azure already implemented the RHEL pricing changes in early 2024. This meter ID update is purely a technical billing system change and does not affect your costs in any way. For pricing information, see the Pricing - Red Hat Virtual Machines | Microsoft Azure page. Action Required: Update Your Billing Tools To ensure uninterrupted monitoring and reporting, we recommend reviewing and updating the following: Billing Reports and Dashboards Cost Management Reports: Update any custom reports that filter by specific RHEL meter IDs Power BI Dashboards: Refresh data connections and update meter ID filters Third-party Tools: Verify that cost management tools recognize the new meter IDs Budget Alerts and Monitoring Budget Configurations: Review budgets that target specific RHEL services and update meter ID filters Cost Alerts: Ensure automated cost alerts include both old and new meter IDs during the transition period Spending Thresholds: Update any spending controls that rely on meter ID identification Automated Tools and Scripts Cost Analysis APIs: Update API calls that reference specific RHEL meter IDs Automation Scripts: Modify any scripts that process billing data using meter ID filters Integration Tools: Update third-party integrations that rely on meter ID mapping Transition Period Support During the migration period, you may see both old and new meter IDs in your statements. This is expected behavior as the transition occurs gradually across different regions and services. Timeline: October 2-8, 2025: New meter IDs begin appearing for RHEL Pay as you go meters Transition Period: Both old and new meter IDs may appear in billing during migration Completion: Migration will be completed across all regions and services Affected RHEL Meters The following RHEL meter names will be updated with new meter IDs as part of this migration: 1 vCPU VM License 1 vCPU VM License - Free 2 vCPU VM License 4 vCPU VM License 6 vCPU VM License 8 vCPU VM License 12 vCPU VM License 16 vCPU VM License 20 vCPU VM License 24 vCPU VM License 32 vCPU VM License 40 vCPU VM License 44 vCPU VM License 48 vCPU VM License 52-vCPU VM License 60 vCPU VM License 64 vCPU VM License 72 vCPU VM License 80 vCPU VM License 96 vCPU VM License 120 vCPU VM License 128 vCPU VM License 144-vCPU VM License 192 vCPU VM License 192-vCPU VM License 208 vCPU VM License 416 vCPU VM License 420-vCPU VM License These meter changes are tied to the vCPU count, not the VM family - meaning any VM with the same vCPU count (whether D family, E family, etc.) uses the same RHEL license meter. For example, all 2 vCPU VMs use the "2 vCPU VM License" meter regardless of the VM family. If your billing reports, budgets, or automated tools currently filter or reference any of these specific meter names, you'll need to update them to include the new meter IDs once the migration begins. Support and Resources Need Help? Azure Support: Contact Azure Support for technical assistance with billing or meter ID questions Account Team: Reach out to your Microsoft account team for guidance on updating enterprise billing processes Additional Resources: RHEL pricing update details: Red Hat Enterprise Linux Pricing update Azure cost optimization resources can be found here Frequently Asked Questions Q: Will this affect my RHEL instances or their performance? A: No, this is purely a billing system update. Your RHEL instances will continue to operate normally with no performance impact. Q: How can I identify the new meter IDs in my billing? A: New meter IDs will appear in your Cost Management portal and usage reports and cost management statements starting October 2-8, 2025. Watch for updated RHEL service descriptions in your billing details. Q: What if my automated tools stop working? A: Contact Azure Support for assistance. We recommend updating your tools proactively using the meter ID mapping reference provided. We're committed to making this transition as smooth as possible. If you have questions or need assistance, please reach out to Azure Support or your Microsoft account team.
Azure Linux Now Supports AKS Long-Term Support (LTS) Starting with Kubernetes v1.28+
What’s New Managing Kubernetes upgrades can be a challenge for many organizations. The fast-paced release cycle requires frequent cluster updates, which can be time-consuming, carry operational risks, and require repeated validation of workloads and infrastructure. To address this, in April of this year, Azure Kubernetes Service (AKS) introduced Long-Term Support (LTS) on every AKS version — beginning with Kubernetes version 1.28. With AKS LTS, every community-released version of Kubernetes receives an extended support window of an additional year, giving customers more time to test, validate, and adopt new versions at a pace that suits their business needs. The Azure Linux team is excited to announce that Azure Linux now also supports AKS LTS starting with Kubernetes version 1.28 and above. This means you can now pair a stable, enterprise-grade node operating system with the extended lifecycle benefits of AKS LTS — providing a consistent, secure, and well-maintained platform for your container workloads. Benefits of Azure Linux with your AKS LTS Clusters Secure by Design: Azure Linux is built from source using Microsoft’s trusted pipelines, with a minimal package set that reduces the attack surface. It is FIPS-compliant and meets CIS Level 1 benchmarks. Operational Stability: With AKS LTS, each version is supported for two years, reducing upgrade frequency and providing a predictable, stable platform for mission-critical workloads. Reliable Updates: Every package update is validated by both the Azure Linux and AKS teams, running through a full suite of tests to prevent regressions and minimize disruptions. Broad Compatibility: Azure Linux supports AKS extensions, add-ons, and open-source projects. It works seamlessly with existing Linux based containers and includes the upstream containerd runtime. Advanced Isolation: It is the only OS on AKS that supports pod sandboxing, enabling compute isolation between pods for enhanced security. Seamless Migration: Customers can migrate from other distributions to Azure Linux nodepools in-place without recreating clusters, simplifying the process. Getting Started Getting started with Azure Linux on AKS LTS is simple and can be done with a single command. See full documentation on getting started with AKS Long-term Support here. Please note that when enabling LTS on a new Azure Linux cluster you will need to specify --os-sku AzureLinux. Considerations LTS is available on the Premium tier. Refer to the Premium tier pricing for more information. Some add-ons and features might not support Kubernetes versions outside upstream community support windows. View unsupported add-ons and features here. Please note Azure Linux 2.0 is the default node OS for AKS versions v1.27 to v1.31 during both Standard and Long-Term Support. However, Azure Linux 2.0 will reach End of Life during the LTS period of AKS v1.28–v1.31. To maintain support and security updates, customers running Azure Linux 2.0 on AKS v1.28–v1.31 LTS are requested to migrate to Azure Linux 3.0 by November 2025. Azure Linux 3.0 has been validated to support AKS Kubernetes v1.28–v1.31. Before Azure Linux 2.0 goes EoL, AKS will offer a feature to facilitate an in-place migration from Azure Linux 2.0 to 3.0 via a node pool update command. For feature availability and updates, see GitHub issue. After November 2025 Azure Linux 2.0 will no longer receive updates, security patches, or support, which may put your systems at risk. AKS version Azure Linux version during AKS Standard Support Azure Linux version during AKS Long-Term Support 1.27 Azure Linux 2.0 Azure Linux 2.0 1.28 - 1.31 Azure Linux 2.0 Azure Linux 2.0 (migrate to 3.0 by Nov 2025) 1.32+ Azure Linux 3.0 Azure Linux 3.0 For more information on the Azure Linux Container Host support lifecycle see here. How to Keep in Touch with the Azure Linux Team: For updates, feedback, and feature requests related to Azure Linux, there are a few ways to stay connected to the team: We have a public community call every other month for Azure Linux users to come together to ask questions, share learnings, and get updates. Join the next community call on July 24 th at 8AM PST: here Partners with support questions can reach out to AzureLinuxISV@microsoft.comBoost your network performance on Linux VMs on Azure
Imagine running a marathon while wearing ankle weights—that’s what it feels like when your Linux VM struggles with network performance issues. Slow data transfers and bottlenecks can keep your systems from reaching their full potential. But here’s the good news: you don’t need to settle for suboptimal speeds anymore. Power of collaboration Just like a relay race requires teamwork to achieve the best result, optimizing your Linux VM's network performance on Azure works best when you combine tools, techniques, and community insights. By pooling knowledge from system administrators, developers, and Azure experts, you can explore a range of solutions designed to tackle common network challenges. Consider experimenting with adjustments to network buffer settings, congestion control algorithms, and queue disciplines to enhance data throughput and resource efficiency. These suggestions provide a foundation to transform the way your systems handle data traffic, offering opportunities to boost performance. And the best part? Everything is open for customization to suit your needs. Why It Matters In today’s fast-paced world, every second counts. Delays in network performance can mean missed opportunities and wasted resources. By implementing optimizations, you’ll have the chance to achieve: Faster data transfers: Move large files between regions without the headache of constant delays. Improved resource utilization: Handle data traffic more efficiently, reducing wasted bandwidth. Scalability: Make your systems ready to grow with your business needs. Take Action Today Don’t let your systems run with ankle weights any longer. Dive into the technical details and explore the solutions by visiting this link. Whether you’re a seasoned system administrator or a business leader looking for better results, this is your opportunity to collaborate, innovate, and maximize performance. To learn more, read the documentation.
