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authorAdrian Reber <areber@redhat.com>2021-12-21 16:01:53 +0000
committerAdrian Reber <areber@redhat.com>2021-12-23 09:51:38 +0000
commitd669dbfb9fbb4bae56ba90ce9b58352c793eff6e (patch)
tree60b8c68575360fa10ebb390eea542ce3b2e5b4a7 /docs
parentb746b22564298463ebf322d630488236b7277074 (diff)
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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>
Diffstat (limited to 'docs')
-rw-r--r--docs/source/markdown/podman-container-checkpoint.1.md12
1 files changed, 12 insertions, 0 deletions
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".