Introduction

The Linux Containers project maintains Long Term Support (LTS) releases for its core projects. Those come with 5 years of support from upstream with the first two years including bugfixes, minor improvements and security fixes and the remaining 3 years getting only security fixes.

This is now the fourth round of bugfix releases for LXC, LXCFS and Incus 6.0 LTS.

LXC

LXC is the oldest Linux Containers project and the basis for almost every other one of our projects. This low-level container runtime and library was first released in August 2008, led to the creation of projects like Docker and today is still actively used directly or indirectly on millions of systems.

Announcement: https://discuss.linuxcontainers.org/t/lxc-6-0-4-lts-has-been-released/23390

Highlights of this point release:

• Switch to the Zabbly MAC address prefix
• New LXC_IPV6_ENABLE lxc-net configuration key to turn IPv6 on/off
• Fixed ability to attach to application containers with non-root entry point

LXCFS

LXCFS is a FUSE filesystem used to workaround some shortcomings of the Linux kernel when it comes to reporting available system resources to processes running in containers. The project started in late 2014 and is still actively used by Incus today as well as by some Docker and Kubernetes users.

Announcement: https://discuss.linuxcontainers.org/t/lxcfs-6-0-4-lts-has-been-released/23389

Highlights of this point release:

• Properly handle SLAB reclaimable memory in meminfo
• Handle empty cpuset strings
• Fix potential sleep interval overflows

Incus

Incus is our most actively developed project. This virtualization platform is just over a year old but has already seen over 3500 commits by over 120 individual contributors. Its first LTS release made it usable in production environments and significantly boosted its user base.

Announcement: https://discuss.linuxcontainers.org/t/incus-6-0-4-lts-has-been-released/23391

Highlights of this point release:

• Instance network ACLs on bridge networks
• Enhanced QEMU scriptlets
• VM memory dumps
• Extended OVN network state information
• Extended server preseed file support
• ACME DNS-01 support
• API wide collection filtering
• SMBIOS11 VM provisioning support
• IOMMU support for VMs
• VRF support for routed NICs
• New MAC address range
• USB NICs in VMs
• USB disks in VMs
• Configurable DNS servers in networks
• Extra IPv4 routes through DHCP

Distrobuilder

Distrobuilder is our image building tool, used to build all our public images.

Due to the nature of this tool, it doesn’t get LTS releases as its feature set is extremely stable but still needs to receive very frequent updates to handle changes in the various Linux distributions that it builds. Distrobuilder 3.2 was released at the same time as the LTS releases, providing an up to date snapshot of that project.

Announcement: https://discuss.linuxcontainers.org/t/distrobuilder-3-2-has-been-released/23385

Highlights from this release:

• Improve Windows driver handling
• Support for newer NixOS releases
• systemd generator handles newer Linux distributions
• Support for Alpaquita

What’s next?

We’re expecting another LTS bugfix release for the 6.0 branches in the third quarter of 2025.
In the mean time, Incus will keep going with its usual monthly feature release cadence.

Thanks

This LTS release update was made possible thanks to funding provided by the Sovereign Tech Fund (now part of the Sovereign Tech Agency).

The Sovereign Tech Fund supports the development, improvement, and maintenance of open digital infrastructure. Its goal is to sustainably strengthen the open source ecosystem, focusing on security, resilience, technological diversity, and the people behind the code.

Find out more at: https://www.sovereign.tech