# Removing a Node

#### Scenario

Removing a node from a cluster in CCE will re-install the node OS and clear CCE components on the node.

Removing a node will not delete the server (ECS) corresponding to the node. You are advised to remove nodes at off-peak hours to avoid impacts on your services.

After a node is removed from the cluster, the node is still running and incurs fees.

#### Notes and Constraints

- Nodes can be removed only when the cluster is in the Available or Unavailable state.
- A CCE node can be removed only when it is in the Active, Abnormal, or Error state.
- A CCE node in the Active state can have its OS re-installed and CCE components cleared after it is removed.
- If the OS fails to be re-installed after the node is removed, manually re-install the OS. After the re-installation, log in to the node and run the clearance script to clear CCE components. For details, see Handling Failed OS Reinstallation.

#### Precautions

- Removing a node will lead to pod migration, which may affect services. Perform this operation during off-peak hours.
- Unexpected risks may occur during the operation. Back up data in advance.
- While the node is being deleted, the backend will set the node to the unschedulable state.
- After you remove the node and re-install the OS, the original LVM partitions will be cleared and the data managed by LVM will be cleared. Therefore, back up data in advance.

#### Procedure

1. Log in to the CCE console. In the navigation pane, choose Resource Management > Nodes. In the same row as the target node, choose More > Remove.
2. In the dialog box displayed, enter REMOVE, configure the login information required for re-installing the OS, and click Yes. Wait until the node is removed.

   After the node is removed, workload pods on the node are automatically migrated to other available nodes.

#### Handling Failed OS Reinstallation

You can perform the following steps to re-install the OS and clear the CCE components on the node if previous attempts fail:

1. Log in to the management console of the server and re-install the OS.
2. Log in to the server and run the following commands to clear the CCE components and LVM data:

   Write the following scripts to the clean.sh file:

       lsblk
       vgs --noheadings | awk '{print $1}' | xargs vgremove -f
       pvs --noheadings | awk '{print $1}' | xargs pvremove -f
       lvs --noheadings | awk '{print $1}' | xargs -i lvremove -f --select {}
       function init_data_disk() {
           all_devices=$(lsblk -o KNAME,TYPE | grep disk | grep -v nvme | awk '{print $1}' | awk '{ print "/dev/"$1}')
           for device in ${all_devices[@]}; do
               isRootDisk=$(lsblk -o KNAME,MOUNTPOINT $device 2>/dev/null| grep -E '[[:space:]]/$' | wc -l )
               if [[ ${isRootDisk} != 0 ]]; then
                   continue
               fi
               dd if=/dev/urandom of=${device} bs=512 count=64
               return
           done
           exit 1
       }
       init_data_disk
       lsblk

   Run the following command:

   bash clean.sh

Parent topic: Nodes