Signed-off-by: Dan Smith <danms@xxxxxxxxxx> --- Documentation/checkpoint/readme.txt | 21 +++++++++++++++++++++ 1 files changed, 21 insertions(+), 0 deletions(-) diff --git a/Documentation/checkpoint/readme.txt b/Documentation/checkpoint/readme.txt index 0553d90..d74c144 100644 --- a/Documentation/checkpoint/readme.txt +++ b/Documentation/checkpoint/readme.txt @@ -365,6 +365,27 @@ It should always be safe to take a checkpoint of an application under LSM_1, and restart it without the RESTART_KEEP_LSM flag under LSM_2. +Sockets +======= + +For AF_UNIX sockets, both endpoints must be within the checkpointed +task set to maintain a connected state after restart. UNIX sockets +that are in the process of passing a descriptor will cause the +checkpoint to fail with -EBUSY indicating a transient state that +cannot be checkpointed. Listening sockets with an unaccepted peer +will also cause an -EBUSY result. + +AF_INET sockets with endpoints outside the checkpointed task set may +remain open if care is taken to avoid TCP timeouts and resets. +Careful use of a virtual IP address can help avoid emission of an RST +to the non-checkpointed endpoint. If desired, the +RESTART_SOCK_LISTENONLY flag may be passed to the restart syscall +which will cause all connected AF_INET sockets to be closed during the +restore process. Listening sockets will still be restored to their +original state, which makes this mode a candidate for something like +an HTTP server. + + Kernel interfaces ================= -- 1.6.2.5 _______________________________________________ Containers mailing list Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/containers
