What can change after C/R

This page is very important (I believe). It describes what can change in a tasks' environment after a C/R cycle. If a software you're using depends on either item from the list below, it may break after C/R. The list is incomplete, but we do our best to make it contain relevant data.

Per-task statistics

Various counters, that can be obtained via /proc/$pid/status or getrusage()

Namespaces' IDs

Numbers you see in the /proc/$pid/ns/* links' targets

Process start time

It's in the 22nd field of the /proc/$pid/stat file

Mount points IDs

The numbers from first 2 columns of /proc/$pid/mountinfo

Sockets IDs

If you stat() a file descriptor with a socket the st_ino value can be used as unique socket ID. This value does changes after C/R as these IDs are global and we have no API to restore one.

VDSO

The VDSO is a shared library linked into app by kernel. If the C/R cycle implies changing the kernel in between (e.g. live migration or seamless kernel upgrade, the VDSO contents may change. However, its linkage with the application is preserved.