# Cetrifuge Chain Node Upgrade Guide

###### tags: `chain`
###### tags: `node-upgrade`

We are planning to upgrade the current Node, which is built on alpha-3 of substrate, to RC6 built in a effort to be as close to the Substrate V2 as possible. The Node upgrade is mandatory since this is a pre-requisite for the following runtime upgrade. There are multiple steps involved in migrating from existing nodes.

**Note**: Please note that this is not a runtime upgrade but Node upgrade which runs the Runtime. The Current runtime version is 229 and will remain 229 after the Node upgrade as well.

## Node details:

Docker Image: `centrifugeio/centrifuge-chain:20200928161532-a960a81`

Release: https://github.com/centrifuge/centrifuge-chain/releases/tag/v2.0.0-rc6

Please use either the Docker Image or build a new Node from the release mentioned above to run the Node.

## Bootnodes:
### Flint:

/ip4/35.246.197.135/tcp/30333/p2p/12D3KooWBF1RdctVztxLLzEwUiuMtqEDVicCjVCS8eyxh71nonxz
/ip4/34.89.219.76/tcp/30333/p2p/12D3KooWNHRdve4U1rsZsDnTKbY8C94Y7VJTrifBy9P2LXLDhCnG

### Amber:

/ip4/34.107.94.59/tcp/30333/p2p/12D3KooWQ3YL8sP2M1S9PVNj8JjmACUjawwRPckzL8fJmXZ7YRPY
/ip4/35.242.247.213/tcp/30333/p2p/12D3KooWECFKJirQiVHeidSkwrEocPr7wkUw3ijbJKNyvCVd3xcu

### Mainnet:

/ip4/34.89.245.58/tcp/30333/p2p/12D3KooWAVAMPNJywZS3J4be8gFGZACfgt1rXS3MyJ2MxEGtLXjr
/ip4/35.246.188.4/tcp/30333/p2p/12D3KooWCUjDbbhJf1o6skuE1EJ5PnKpJMaK6scmvWsHnjAULzDU

## Vocabulary
Node(A) => New Node built using RC6
Node(B) => Currently running Node

## Validator without Sentry setup:
- Start a new Validator Node(A) while your exisiting Validator Node(B) is still validating and producing blocks.
- **It is important that `Node Key` for Node(A) must be different from the Node(B) else your Validator will get slashed.**
- Get your Node(A) fully synced with the Network (*it may take up to 1 day to sync*)
- At this point, your Node(B) will still be validating and producing the blocks.
- Here is the example log when your validator proposed a new block
- Once the Node(A) is fully synced with the Network, generate a new session key using `author_rotateKeys` Node(A)'s RPC.
- Here is the curl command for the same.

- Copy the generated session key from the response and update your Validator account with this session key using `Change session keys` option as shown below.
- ![](https://storage.googleapis.com/centrifuge-hackmd/upload_1a8aad3197ebc88c13470c17b95ce92d.png)
- Once the session key is updated, Node(A) will start producing blocks in the **sesssion after the next session**. In the meantime, Node(B) validator should still be producing blocks.
- Once the new session keys are loaded, your Node(A) will start producing the blocks. You can identify this by looking at the logs of Node(A).
- ![](https://storage.googleapis.com/centrifuge-hackmd/upload_a796eec127d52070cff8d3636b0df45e.png)
- Once Node(A) is confirmed producing blocks, Node(B) can be decomissioned.

## Validator with Sentry Nodes:
**Parity recently accounced that Sentry feature will be dropped by Oct 2020. More information on this can be found here - https://github.com/paritytech/substrate/issues/6845
They highly recommended to decomisssion sentry setup sooner before the support for Sentry is removed.**

Upgrading Node in the sentry setup will be similar to Single validator node.
- Instead of starting a single validator node, we suggest starting full sentry node setup. 
- Once all the sentries and validator nodes fully synced with the network, changing session keys are same as Single node Validator.
- Once the new Validator behind the new Sentries is producing the blocks, you can decomission the old Sentry setup.