Action scripts

With the --action-script command line option, CRIU can call your action scripts (also known as hooks) at various stages of dumping/restoring. Hooks can be one of

network-lock

request to lock a container network (used by Docker and LXC)

network-unlock

requested to unlock a container network (used by Docker and LXC)

post-dump

called when CRIU finished dumping tasks before unfreezing them

post-restore

called when CRIU has finished restoring tasks before unlocking the network

setup-namespaces

called when the root task is alive and new set of namespaces is created to set them up

CLI

These hooks are added with the --action-script shell-code-to-execute option. When called, the CRTOOLS_SCRIPT_ACTION environment is set to a value determining which type of action is performed.

RPC

In case or RPC, action scripts are implemented as notifications -- once CRIU service wants to execute a script it send an RPC message to caller and waits for it to respond with criu_req message having notify_success = true.

Library

When using a library one can setup a callback using the criu_set_notify routine.