What CRtools is

CRtools is an utility to checkpoint/restore process tree. Unlike checkpoint/restore implemented completely in kernel space, it tries to achieve the same target operating in user space. Since the tools and overall concept are still under heavy development stage there are some known limitations applied, in particular only pure x86-64 environment is supported, no IA32 emulation allowed.

Download crtools

The crtools utility itself is hosted at git.criu.org. Clone this repo to test new functionality. Anything but master branch are development ones, don't refer on them.

Before building also install the C bindings for Google's Protocol Buffers. In rpm-based distros this is protobuf-c package.

The run make in the sources root.

Configure the linux kernel

Make sure you have the following options turned on

  • General setup -> Checkpoint/restore support (CONFIG_CHECKPOINT_RESTORE)
  • General setup -> open by fhandle syscalls (CONFIG_FHANDLE)
  • General setup -> Enable eventfd() system call (CONFIG_EVENTFD)
  • General setup -> Enable eventpoll support (CONFIG_EPOLL)
  • File systems -> Inotify support for userspace (CONFIG_INOTIFY_USER)
  • Networking support -> Networking options -> Unix domain sockets -> UNIX: socket monitoring interface (CONFIG_UNIX_DIAG)
  • Networking support -> Networking options -> TCP/IP networking -> INET: socket monitoring interface (CONFIG_INET_DIAG)

Note you might have to enable

  • General setup -> Configure standard kernel features (expert users) (CONFIG_EXPERT)

option, which depends on

  • General setup -> Embedded system (CONFIG_EMBEDDED)

(welcome to Kconfig reverse chains hell).

The v3.5 upstream kernel already has most of the required functionality merged. Some is sill out-of-tree though, so you might need to clone the linux-2.6-crtools.git, checkout the crtools-3.5 branch and compile the kernel.

Checking how it works

You can first look into the ZDTM Test Suite which sits in the tests/zdtm/ directory.

Using CR tools

Please see running CR tools article.

CR tools mailing list

If you're interested in CR tools development don't hesitate to subscribe to the CRtools mailing list which can be found here [1].