Merge pull request #828 from s1061123/dev/chroot

Add chroot option in multus-daemon

docs/how-to-use.md

@@ -39,7 +39,7 @@ cat >/etc/cni/net.d/00-multus.conf <<EOF
 {
   "name": "multus-cni-network",
   "type": "multus",
-  "readinessindicatorfile": "/var/run/flannel/subnet.env",
+  "readinessindicatorfile": "/run/flannel/subnet.env",
   "delegates": [
     {
       "NOTE1": "This is example, wrote your CNI config in delegates",

docs/thick-plugin.md

@@ -79,7 +79,14 @@ specifies the path to the server configuration:
 
 The server configuration is encoded in JSON, and allows the following keys:
 
+- `"chrootDir"`: Specify the directory which points to host root from the pod. See 'Chroot configuration' section for the details.
 - `"socketDir"`: Specify the location where the unix domain socket used for
-client/server communication will be located. Defaults to `"/var/run/multus-cni/"`.
+client/server communication will be located. Defaults to `"/run/multus-cni"`.
 
 In addition, you can add any configuration which is in [configuration reference](https://github.com/k8snetworkplumbingwg/multus-cni/blob/master/docs/configuration.md#multus-cni-configuration-reference). Server configuration override multus CNI configuration (e.g. `/etc/cni/net.d/00-multus.conf`)
+
+#### Chroot configuration
+
+In thick plugin case, delegate CNI plugin is executed by multus-daemon from Pod, hence if the delegate CNI requires resources in container host, for example unix socket or even file, then CNI plugin is failed to execute because multus-daemon runs in Pod. Multus-daemon supports "chrootDir" option which executes delegate CNI under chroot (to container host).
+
+This configuration is enabled in deployments/multus-daemonset-thick.yml as default.