Proposals

Live migration of hidden files

This proposal has been rejected.

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One Line Summary

Presentation describes ways to migrate opened files that are no longer accessible from the filesystem.

Abstract

In the course of live migration of an OpenVZ Linux container, we have encountered a problem of migrating files which do not appear in a the filesystem tree.

When we checkpoint an opened file, we store the full filename to an image file, and on the restore stage we try to open the file by this name. There are cases when an opened file is inaccessible by the name. First, another filesystem can be mounted to some parent directory (so called overmount). Second, the file is unlinked. In both cases restoration by a file name no longer works.

To solve such issues, we found ways to store the path that at the restoring time will point to the desired file, plus some VFS trickery at a time of restore.

Tags

kernel, openvz, checkpointing, live migration

Speakers

  • Biography

    Pavel Emelyanov is a core OpenVZ and PVC kernel developer working in the project for the last six years. His current role is the kernel team leader. Pavel is also the leading force behind a few mainstream kernel features, such as the network and the PID namespaces. He holds a PhD in Mathematics from the Moscow Institute of Physics and Technology.

  • Kir Kolyshkin

    OpenVZ

    Biography

    Kirill Kolyshkin was named leader and project manager for the OpenVZ project in 2005 to further the adoption of containers virtualization for Linux. He spearheads the overall development and manages all key architecture, updates and feature upgrades for OpenVZ. Kolyshkin has more than 10 years of Linux experience and has long been an active open source advocate. He is a frequent speaker about virtualization technology and his 15-years career experience includes positions in information technology at Deutsche Bank and telecommunications company, Severtelecom. He holds a degree in Computer Science from the Ukhta State Technical University.

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