From eb94467780eab06a452586c9751fc4f571d9e089 Mon Sep 17 00:00:00 2001 From: Adrian Reber Date: Mon, 12 Jul 2021 11:43:45 +0000 Subject: Support checkpoint/restore with pods This adds support to checkpoint containers out of pods and restore container into pods. It is only possible to restore a container into a pod if it has been checkpointed out of pod. It is also not possible to restore a non pod container into a pod. The main reason this does not work is the PID namespace. If a non pod container is being restored in a pod with a shared PID namespace, at least one process in the restored container uses PID 1 which is already in use by the infrastructure container. If someone tries to restore container from a pod with a shared PID namespace without a shared PID namespace it will also fail because the resulting PID namespace will not have a PID 1. Signed-off-by: Adrian Reber --- pkg/checkpoint/crutils/checkpoint_restore_utils.go | 11 +++++++++++ 1 file changed, 11 insertions(+) (limited to 'pkg/checkpoint/crutils') diff --git a/pkg/checkpoint/crutils/checkpoint_restore_utils.go b/pkg/checkpoint/crutils/checkpoint_restore_utils.go index 53ff55865..3b77368bb 100644 --- a/pkg/checkpoint/crutils/checkpoint_restore_utils.go +++ b/pkg/checkpoint/crutils/checkpoint_restore_utils.go @@ -1,6 +1,7 @@ package crutils import ( + "bytes" "io" "os" "os/exec" @@ -189,3 +190,13 @@ func CRRuntimeSupportsCheckpointRestore(runtimePath string) bool { } return false } + +// CRRuntimeSupportsCheckpointRestore tests if the runtime at 'runtimePath' +// supports restoring into existing Pods. The runtime needs to support +// the CRIU option --lsm-mount-context and the existence of this is checked +// by this function. In addition it is necessary to at least have CRIU 3.16. +func CRRuntimeSupportsPodCheckpointRestore(runtimePath string) bool { + cmd := exec.Command(runtimePath, "restore", "--lsm-mount-context") + out, _ := cmd.CombinedOutput() + return bytes.Contains(out, []byte("flag needs an argument")) +} -- cgit v1.2.3-54-g00ecf