LXD/LXC/LXCFS version 4 Released, with virtual machine support for LXC

March 31, development teams of system container LXD and its related technologies LXC and LXCFS have each announced their major release “LXD 4.0”, “LXC 4.0”, and “LXCFS 4.0”.  They are LTS releases, which will be supported till June 2025.

LXC is a container runtime written in C, and it can run both system containers and application containers.  LXD is a system container and virtual machine manager, and it can run several thousand containers on a single machine.  It is implemented as Go application based on LXC and QEMU.  Linux Containers is sponsored by Canonical.

LXC is a major release following version 3, which was released in 2018.  It includes full support for CGroup2, along with Freezer support and eBPF device controller support.  It also introduces a mechanism for system call interception within containers.

LXD 4.0 introduces virtual machine backup feature.  Now “lxc export” and “lxc import” commands can be used to execute import and export.  There are also network feature improvements, for example it now allows multiple ipvlan devices added to the same container. “Projects” feature manages instances, images, profiles, and storage volumes in a container by segmenting the LXD server.  Another feature to highlight is the automated snapshots for instances and storage volumes.  It introduces support for CGroup 2 and Nftable, and CephFS is added as a custom volume storage backend.

LXCFS is a FUSE-based filesystem, which provides bind-mount function over /proc directories.  This is used for purposes like letting non-authority users execute systemd-based containers.  Support for CGroups2 and pidfd is added to LXDFS 4.0, and therefore codebase has been improved.

LXD 4.0, LXC 4.0, and LXCFS 4.0 are available on the project page of Linux Containers.

Linux Containers
https://linuxcontainers.org/