*: update drainExecSyncIO docs and validate the timeout

We should validate the drainExecSyncIO timeout at the beginning and
raise the error for any invalid input.

Signed-off-by: Wei Fu <fuweid89@gmail.com>

docs/cri/config.md

@@ -227,6 +227,16 @@ version = 2
   # https://github.com/container-orchestrated-devices/container-device-interface#containerd-configuration
   cdi_spec_dirs = ["/etc/cdi", "/var/run/cdi"]
 
+  # drain_exec_sync_io_timeout is the maximum duration to wait for ExecSync API'
+  # IO EOF event after exec init process exits. A zero value means there is no
+  # timeout.
+  #
+  # The string is in the golang duration format, see:
+  #    https://golang.org/pkg/time/#ParseDuration
+  #
+  # For example, the value can be '5h', '2h30m', '10s'.
+  drain_exec_sync_io_timeout = "0s"
+
   # 'plugins."io.containerd.grpc.v1.cri".containerd' contains config related to containerd
   [plugins."io.containerd.grpc.v1.cri".containerd]
 

pkg/cri/config/config.go

@@ -357,6 +357,8 @@ type PluginConfig struct {
 	//
 	// The string is in the golang duration format, see:
 	//   https://golang.org/pkg/time/#ParseDuration
+	//
+	// For example, the value can be '5h', '2h30m', '10s'.
 	DrainExecSyncIOTimeout string `toml:"drain_exec_sync_io_timeout" json:"drainExecSyncIOTimeout"`
 }
 

pkg/cri/config/config_unix.go

@@ -110,6 +110,6 @@ func DefaultConfig() PluginConfig {
 		EnableCDI:                false,
 		CDISpecDirs:              []string{"/etc/cdi", "/var/run/cdi"},
 		ImagePullProgressTimeout: time.Minute.String(),
-		DrainExecSyncIOTimeout:   "0",
+		DrainExecSyncIOTimeout:   "0s",
 	}
 }

pkg/cri/config/config_windows.go

@@ -86,6 +86,6 @@ func DefaultConfig() PluginConfig {
 			KeyModel: KeyModelNode,
 		},
 		ImagePullProgressTimeout: time.Minute.String(),
-		DrainExecSyncIOTimeout:   "0",
+		DrainExecSyncIOTimeout:   "0s",
 	}
 }