diff --git a/docs/csi-config.md b/docs/csi-config.md
index 8dbce88..377b797 100644
--- a/docs/csi-config.md
+++ b/docs/csi-config.md
@@ -1,57 +1,11 @@
-# Longhorn CSI on RancherOS/CoreOS + RKE or K3S
+# Longhorn CSI on K3S
 
 ## Requirements
   1. Kubernetes v1.11 or higher.
   2. Longhorn v0.4.1 or higher.
-  3. For RancherOS only: Ubuntu console.
 
 
 ## Instruction
-### For RancherOS/CoreOS + Kubernetes v1.11 only 
-  The following step is not needed for Kubernetes v1.12 and above.
-
-  Add extra_binds for kubelet in RKE `cluster.yml`:
-  ```
-   services:
-     kubelet:
-       extra_binds:
-       - "/opt/rke/var/lib/kubelet/plugins:/var/lib/kubelet/plugins" 
-   ```
-   
-### For each node:
-#### RancherOS:
-  ##### 1. Switch to ubuntu console
-
-  `sudo ros console switch ubuntu`, then type `y`
-
-  ##### 2. Install open-iscsi for each node. 
-  ```
-  sudo apt update
-  sudo apt install -y open-iscsi
-  ```
-  ##### 3. Modify configuration for iscsi. 
-    
-  1. Open config file `/etc/iscsi/iscsid.conf`
-  2. Comment `iscsid.startup = /bin/systemctl start iscsid.socket`
-  3. Uncomment `iscsid.startup = /sbin/iscsid`
-
-#### CoreOS:    
-
-  #####  1. If you want to enable iSCSI daemon automatically at boot, you need to enable the systemd service:
-
-  ```
-  sudo su
-  systemctl enable iscsid
-  reboot
-  ```
-  
-  #####  2. Or just start the iSCSI daemon for the current session:
-
-  ```
-  sudo su
-  systemctl start iscsid
-  ```
-
 #### K3S: 
   ##### 1. For Longhorn v0.7.0 and above
   Longhorn v0.7.0 and above support k3s v0.10.0 and above only by default. 
@@ -73,21 +27,6 @@ This error is due to Longhorn cannot detect where is the root dir setup for Kube
 User can override the root-dir detection by manually setting argument `kubelet-root-dir` here: 
 https://github.com/rancher/longhorn/blob/master/deploy/longhorn.yaml#L329
 
-#### How to find `root-dir`?
-
-**For RancherOS/CoreOS**
- 
-Run `ps aux | grep kubelet` and get argument `--root-dir` on host node. 
-
-e.g.
-```
-$ ps aux | grep kubelet
-root      3755  4.4  2.9 744404 120020 ?       Ssl  00:45   0:02 kubelet --root-dir=/opt/rke/var/lib/kubelet --volume-plugin-dir=/var/lib/kubelet/volumeplugins
-```
-You will find `root-dir` in the cmdline of proc `kubelet`. If it's not set, the default value `/var/lib/kubelet` would be used. In the case of RancherOS/CoreOS, the root-dir would be `/opt/rke/var/lib/kubelet` as shown above.
-
-If kubelet is using a configuration file, you would need to check the configuration file to locate the `root-dir` parameter.
-
 **For K3S v0.10.0-**
 
 Run `ps aux | grep k3s` and get argument `--data-dir` or `-d` on k3s server node.
@@ -107,33 +46,8 @@ If K3S is using a configuration file, you would need to check the configuration
 It is always `/var/lib/kubelet`
 
 ## Background 
-#### CSI doesn't work with RancherOS/CoreOS + RKE before Longhorn v0.4.1 
-The reason is:
-
-1. RKE sets argument `root-dir=/opt/rke/var/lib/kubelet` for kubelet in the case of RancherOS or CoreOS, which is different from the default value `/var/lib/kubelet`.
-                                                                             
-2. **For k8s v1.12 and above**
-
-     Kubelet will detect the `csi.sock` according to argument `<--kubelet-registration-path>` passed in by Kubernetes CSI driver-registrar, and `<drivername>-reg.sock` (for Longhorn, it's `io.rancher.longhorn-reg.sock`) on kubelet path `<root-dir>/plugins`.
-   
-   **For k8s v1.11**
-   
-     Kubelet will find both sockets on kubelet path `/var/lib/kubelet/plugins`.
-   
-3. By default, Longhorn CSI driver create and expose these 2 sock files on host path `/var/lib/kubelet/plugins`.
-
-4. Then kubelet cannot find `<drivername>-reg.sock`, so CSI driver doesn't work.
-
-5. Furthermore, kubelet will instruct CSI plugin to mount Longhorn volume on `<root-dir>/pods/<pod-name>/volumes/kubernetes.io~csi/<volume-name>/mount`.
-
-   But this path inside CSI plugin container won't be binded mount on host path. And the mount operation for Longhorn volume is meaningless.
-   
-   Hence Kubernetes cannot connect to Longhorn using CSI driver.
-   
 #### Longhorn versions before v0.7.0 don't work on K3S v0.10.0 or above
 K3S now sets its kubelet directory to `/var/lib/kubelet`. See [the K3S release comment](https://github.com/rancher/k3s/releases/tag/v0.10.0) for details.
 
 ## Reference
 https://github.com/kubernetes-csi/driver-registrar
-
-https://coreos.com/os/docs/latest/iscsi.html