From d669dbfb9fbb4bae56ba90ce9b58352c793eff6e Mon Sep 17 00:00:00 2001 From: Adrian Reber <areber@redhat.com> Date: Tue, 21 Dec 2021 16:01:53 +0000 Subject: Error out early if system does not support pre-copy checkpointing CRIU's pre-copy migration support relies on the soft dirty page tracking in the Linux kernel: https://www.kernel.org/doc/Documentation/vm/soft-dirty.txt This functionality is not implemented for all architectures and it can also be turned off in the kernel. CRIU can check if the combination of architecture/kernel/CRIU supports the soft dirty page tracking and exports this feature checking functionality in go-criu. This commit adds an early check if the user selects pre-copy checkpointing to error out if the system does not support it. Signed-off-by: Adrian Reber <areber@redhat.com> --- docs/source/markdown/podman-container-checkpoint.1.md | 12 ++++++++++++ 1 file changed, 12 insertions(+) (limited to 'docs/source') diff --git a/docs/source/markdown/podman-container-checkpoint.1.md b/docs/source/markdown/podman-container-checkpoint.1.md index e54274775..00d8f7095 100644 --- a/docs/source/markdown/podman-container-checkpoint.1.md +++ b/docs/source/markdown/podman-container-checkpoint.1.md @@ -70,6 +70,13 @@ Dump the *container's* memory information only, leaving the *container* running. operations will supersede prior dumps. It only works on `runc 1.0-rc3` or `higher`.\ The default is **false**. +The functionality to only checkpoint the memory of the container and in a second +checkpoint only write out the memory pages which have changed since the first +checkpoint relies on the Linux kernel's soft-dirty bit, which is not available +on all systems as it depends on the system architecture and the configuration +of the Linux kernel. Podman will verify if the current system supports this +functionality and return an error if the current system does not support it. + #### **--print-stats** Print out statistics about checkpointing the container(s). The output is @@ -126,6 +133,11 @@ Check out the *container* with previous criu image files in pre-dump. It only wo The default is **false**.\ *IMPORTANT: This OPTION is not available with __--pre-checkpoint__*. +This option requires that the option __--pre-checkpoint__ has been used before on the +same container. Without an existing pre-checkpoint, this option will fail. + +Also see __--pre-checkpoint__ for additional information about __--pre-checkpoint__ +availability on different systems. ## EXAMPLES Make a checkpoint for the container "mywebserver". -- cgit v1.2.3-54-g00ecf