5โ€“7 Oct 2026
Europe/Prague timezone

Session

Containers and checkpoint/restore MC

7 Oct 2026, 10:00

Description

The Containers and Checkpoint/Restore micro-conference focuses on both userspace and kernel related work.

The micro-conference targets the wider container ecosystem ideally with participants from all major container runtimes as well as init system developers.

The microconference will be discussing recent advancements in container technologies with some of the usual candidates being:

  • VFS API improvements (new system calls, idmap, โ€ฆ)
  • CGroupV2 feature parity with CGroupV1 and migration path
  • Dealing with the eBPF-ification of the world
  • Mediating and intercepting complex system calls
  • Making user namespaces more accessible
  • Verifying the integrity of containers
  • Improving the set of resource limits available

On the checkpoint/restore front, some of the potential topics include:

  • Making CRIU work with modern Linux distributions
  • Handling GPUs
  • Restoring FUSE daemons
  • Dealing with restartable sequences
  • Use of eBPF
  • Support of new kernel features
  • Supporting shadow stack (x86, arm64)
  • Support for madvise(MADV_GUARD_INSTALL)
  • Support for mseal()
  • Support for pidfd C/R, including process exit information

And quite likely a variety of other container and checkpoint/restore topics as things evolve between now and the event.

Past editions of this micro-conference have been the source of many developments in the Linux kernel, including:

  • PIDfds
  • VFS idmap (and adding it to a slew of filesystems)
  • FUSE in user namespaces
  • Unprivileged overlayfs
  • Time namespace
  • A variety of CRIU features and checkpoint/restore kernel interfaces with the latest among them being
  • Unpriviledged checkpoint/restore
  • Support of rseq(2) checkpointing
  • IMA/TPM attestation work

Presentation materials

There are no materials yet.

  1. Michal Koutnรฝ (SUSE)
    07/10/2026, 10:00

    Triggered by:
    Subject: [PATCH 0/4] bpf: add a few hooks for sandboxing
    Message-Id: 20260220-work-bpf-namespace-v1-0-866207db7b83@kernel.org

    Problem statements:
    - Users (admins) are sometimes confused by some entity (PAM, systemd, container
    runtimes) migrating their processes away from intended cgroup.
    - Coarse-grained DAC doesn't express well who (migrating process) can operate
    ...

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  2. Shailja Shaktawat
    07/10/2026, 10:20

    CRIUโ€™s incremental checkpointing is being used for forensic container snapshot(Stoyanov et al., DFRWS 2026) chains. Soft-dirty tracking cuts snapshot size by about 10ร— and makes high-frequency capture practical. Live migration only needs a correct final state. Forensics needs the path that led there. Soft-dirty was built for migration and is now being reused for forensics.

    A forensic...

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  3. Radostin Stoyanov (University of Oxford)
    07/10/2026, 10:40

    With the increased adoption of AI workloads, efficient GPU checkpointing mechanisms are becoming crucial for inference, training, fine-tuning, and reinforcement learning workloads. One of the key challenges with GPU checkpointing today is the lack of memory-tracking support that enables incremental snapshots. When the GPU state is checkpointed into host memory, all pages appear modified,...

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  4. Andrei Zhadchenko (Virtuozzo)
    07/10/2026, 11:00

    Container storage commonly relies on directory overlays, filesystem-native subvolumes, or thin-provisioned block devices. We will explore another approach: exposing QCOW2 images directly as Linux block devices through a device-mapper target. QCOW2 is the standard virtual-disk format across much of the QEMU/KVM ecosystem. Its widespread adoption, mature tooling, and features such as...

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  5. Jori Koolstra (N/A)
    07/10/2026, 12:00

    For quite a while there has been a wish from container runtime to be able to restrict how we can reuse a particular file descriptor. For instance, CVE-2019-5736 showcased a privilege escalation in runc, whereby the possibility of reopening /proc/self/exe as writeable allowed a malicious image to overwrite the runc binary. That was patched on the user space side by copying runc to a sealed...

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  6. Pavel Tikhomirov
    07/10/2026, 12:20

    After moving OpenVZ containers to cgroup-v2 we are struggling a bit to reach
    feature parity with what we had before. One such feature is running nested
    Docker containers inside an OpenVZ (system) container โ€” part of making our
    containers behave as close to a regular server as possible.

    In cgroup-v2 the device controller was reformed drastically: device
    availability can only be...

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  7. Andrei Vagin
    07/10/2026, 12:40

    Checkpoint/Restore (C/R) is increasingly used for both startup acceleration (restoring pre-warmed snapshot instances on demand) and live migration. However, deploying static snapshots or migrating tasks across heterogeneous clusters creates severe runtime bottlenecks when source and target nodes possess differing CPU capabilities. While CRIU and container runtimes can accurately preserve...

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  8. Michal Koutnรฝ (SUSE)
    07/10/2026, 13:00

    Triggered by:
    a) various rstat fixups as well as people reporting issues with (memory).stat reading vs writing performance & precision
    b) occasional reports/attempts to make container startup quicker

    Problem statements:
    a) cgroup rstats need to balance latency requirements of updaters (writers) and readers while preserving sufficient precision. The improvement for one may cause some...

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