Provide ability to set lo up without CNI

Signed-off-by: Michael Zappa <michael.zappa@gmail.com>

internal/cri/config/config.go

@@ -185,6 +185,8 @@ type CniConfig struct {
 	// * ipv6 - select the first ipv6 address
 	// * cni - use the order returned by the CNI plugins, returning the first IP address from the results
 	IPPreference string `toml:"ip_pref" json:"ipPref"`
+	// UseInternalLoopback specifies if we use the CNI loopback plugin or internal mechanism to set lo to up
+	UseInternalLoopback bool `toml:"use_internal_loopback" json:"useInternalLoopback"`
 }
 
 // Mirror contains the config related to the registry mirror

internal/cri/config/config_unix.go

@@ -77,6 +77,7 @@ func DefaultRuntimeConfig() RuntimeConfig {
 			NetworkPluginMaxConfNum:    1, // only one CNI plugin config file will be loaded
 			NetworkPluginSetupSerially: false,
 			NetworkPluginConfTemplate:  "",
+			UseInternalLoopback:        false,
 		},
 		ContainerdConfig: ContainerdConfig{
 			DefaultRuntimeName: "runc",

internal/cri/config/config_windows.go

@@ -47,6 +47,7 @@ func DefaultRuntimeConfig() RuntimeConfig {
 			NetworkPluginMaxConfNum:    1,
 			NetworkPluginSetupSerially: false,
 			NetworkPluginConfTemplate:  "",
+			UseInternalLoopback:        false,
 		},
 		ContainerdConfig: ContainerdConfig{
 			DefaultRuntimeName: "runhcs-wcow-process",