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1301 - Updated steps for moving a node #1303

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1301 - Updated steps for moving a node #1303

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90 changes: 52 additions & 38 deletions source/docs/casper/operators/maintenance/moving-node.md
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Expand Up @@ -6,68 +6,82 @@ title: Move a Node

This guide is for active validators who want to move their node to another machine.

:::note

Starting with node version 1.5, operators need to move the unit files at the database level. This step allows moving the node with nearly zero rewards loss.

:::

## Swapping Keys with a Hot Backup

This method limits downtime and enables a smooth transition from the old to the new node. It keeps the node in sync with the tip of the chain.

1. Once a node is running (`current_node`), create a second node (`backup_node`) on another machine. These two nodes will run in parallel.
2. When the `backup_node` is up to date, stop both nodes.
3. Swap their associated keys.
4. Restart the `backup_node`.
2. When the `backup_node` is up to date, stop the `current_node`.
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Created a more detailed list here.

3. Move the unit files at the DB level using `rsync`. This step allows moving the node with nearly zero rewards loss.
4. Stop the `backup_node`.
5. Swap keys on the `backup_node`, now the new validator.
6. Restart the `backup_node`.
7. Swap keys on the `current_node`, now the new backup.
8. Restart the `current_node`.

### Preparation for swapping

Let both nodes synchronize to the tip of the blockchain. Keep the current validating node running with the original validator keyset.
1. Let both nodes synchronize to the tip of the blockchain. Keep the current validating node running with the original validator keyset.

Bond the `backup_node` and wait until rewards are issued.
2. Bond the `backup_node` and wait until rewards are issued.

To swap keys:
3. Prepare to swap keys by following these steps:

1. Create the following folder structure on both nodes under the `/etc/casper/validator_keys/` directory.
2. Create subdirectories for the `current_node` and `backup_node`.
3. Copy each node's keyset under the corresponding directories.
- Create the following folder structure on both nodes under the `/etc/casper/validator_keys/` directory.
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Adding steps and reformatting seems nicer to me.

- Create subdirectories for the `current_node` and `backup_node`.
- Copy each node's keyset under the corresponding directories.

```bash
/etc/casper/validator_keys/
├── public_key.pem
├── public_key_hex
├── secret_key.pem
├── current_node
│ ├── public_key.pem
│ ├── public_key_hex
│ └── secret_key.pem
└── backup_node
| ├── public_key.pem
| ├── public_key_hex
| └── secret_key.pem
/etc/casper/validator_keys/
├── public_key.pem
├── public_key_hex
├── secret_key.pem
├── current_node
│ ├── public_key.pem
│ ├── public_key_hex
│ └── secret_key.pem
└── backup_node
| ├── public_key.pem
| ├── public_key_hex
| └── secret_key.pem
```

This setup allows key swapping by running the `sudo -u casper cp * ../` command, as shown below.

### Swapping the nodes

On the `current_node`, run these commands:
1. When the `backup_node` is up to date, stop the `current_node`.

```bash
sudo systemctl stop casper-node-launcher
cd /etc/casper/validator_keys/backup_node
sudo -u casper cp * ../
```
2. On the `backup_node` (the future validator), use `rsync` to move the unit files from the `current_node`, located in `/var/lib/casper/casper-node/[NETWORK_NAME]/unit_files`.

On the `backup_node` (the future validator), run these commands:
3. On the `backup_node`, run these commands to stop the node, swap keys, and restart the node:

```bash
sudo systemctl stop casper-node-launcher
cd /etc/casper/validator_keys/current_node
sudo -u casper cp * ../
sudo systemctl start casper-node-launcher
```
```bash
sudo systemctl stop casper-node-launcher
cd /etc/casper/validator_keys/current_node
sudo -u casper cp * ../
sudo systemctl start casper-node-launcher
```

Restart the original validator node (`current_node`), which is now the new backup:
4. On the `current_node`, run these commands to stop the node and swap keys:

```bash
sudo systemctl start casper-node-launcher
```
```bash
sudo systemctl stop casper-node-launcher
cd /etc/casper/validator_keys/backup_node
sudo -u casper cp * ../
```

5. Restart the original validator node (`current_node`), which is now the new backup:

```bash
sudo systemctl start casper-node-launcher
```

### Understanding rewards impact

Expand Down