docs(consensus): instructions for enabling consensus on the main node

docs/src/guides/advanced/16_decentralization.md

@@ -0,0 +1,104 @@
+# Decentralization
+
+To enable support for synchronization over p2p network, the main node needs to have the "consensus" component configured
+and enabled as follows:
+
+## Generating the consensus secrets
+
+Run the following to generate consensus secrets:
+
+```
+docker run --entrypoint /usr/bin/zksync_external_node "matterlabs/external-node:2.0-v25.1.0" generate-secrets > consensus_secrets.yaml
+chmod 600 consensus_secrets.yaml
+```
+
+## Preparing the consensus config
+
+Create `consensus_config.yaml` file with the following content (remember to replace the placeholders):
+
+```yaml
+server_addr: '0.0.0.0:3054'
+public_addr:
+  # Address under which the node is accessible to the other nodes.
+  # It can be a public domain, like `example.com:3054`, in case the main node is accessible from the internet,
+  # or it can be a kubernetes cluster domain, like `server-v2-core.<cluster name>.svc.cluster.local:3054` in
+  # case the main node should be only accessible within the cluster.
+debug_page_addr: '0.0.0.0:5000'
+max_payload_size: 3200000
+gossip_dynamic_inbound_limit: 10
+genesis_spec:
+  chain_id: # chain id
+  protocol_version: 1 # consensus protocol version
+  validators:
+    - key: validator:public:??? # public key of the main node (copy this PUBLIC key from consensus_secrets.yaml)
+      weight: 1
+  leader: validator:public:??? # same as above - main node will be the only validator and the only leader.
+```
+
+## Providing the configuration to the `zksync_server`
+
+To enable consensus component for the main node you need to append
+`--components=<whatever components you were running until now>,consensus` to the `zksync_server` command line arguments.
+In addition to that, you need to provide the configuration (from the files `consensus_config.yaml` and
+`consensus_secrets.yaml` that we have just prepared) to the `zksync_server` binary. There are 2 ways (hopefully not for
+long) to achieve that:
+
+- In file-based configuration system, the consensus config is embedded in the
+  [general config](https://github.com/matter-labs/zksync-era/blob/1edcabe0c6a02d5b6700c29c0d9f6220ec6fb03c/core/lib/config/src/configs/general.rs#L58),
+  and the consensus secrets are embedded in the
+  [secrets config](https://github.com/matter-labs/zksync-era/blob/main/core/bin/zksync_server/src/main.rs). Paste the
+  content of the generated `consensus_secrets.yaml` file to the `secrets` config, and prepared config to the `general`
+  config.
+
+- In env-var-based configuration system, the consensus config and consensus secrets files are passed as standalone
+  files. The paths to these files need to be passed as env vars `CONSENSUS_CONFIG_PATH` and `CONSENSUS_SECRETS_PATH`.
+
+## Gitops repo config
+
+If you are using the matterlabs gitops repo to configure the main node, it is even more complicated becase the
+`consensus_config.yaml` file is rendered from a helm chart. See the
+[example](https://github.com/matter-labs/gitops-kubernetes/blob/main/apps/environments/mainnet2/server-v2/server-v2-core.yaml),
+to see where you have to paste the content of the `consensus_config.yaml` file.
+
+You need to embed the `consenus_secrets.yaml` file into a kubernetes config:
+
+```yaml
+apiVersion: v1
+kind: Secret
+metadata:
+  name: consensus-secrets
+type: Opaque
+stringData:
+  .consensus_secrets.yaml: <here goes the content of the consensus_secrets.yaml file>
+```
+
+You need to add the following sections to your kubernetes config for the core server:
+
+```yaml
+spec:
+  values:
+    persistence:
+      consensus-secrets-volume:
+        name: consensus-secrets # this is the name of the secret kubernetes object we defined above
+        enabled: true
+        type: secret
+        mountPath: '/etc/consensus_secrets/'
+    args:
+      - --components=state_keeper,consensus
+    service:
+      main:
+        ports:
+          consensus:
+            enabled: true
+            port: 3054
+    configMap:
+      consensus:
+        enabled: true
+        data:
+          consensus_config.yaml: <here goes the content of the consensus_config.yaml file>
+    env:
+      - name: CONSENSUS_CONFIG_PATH
+        value: /etc/consensus_config.yaml # this is the location rendered by the helm chart, you can't change it
+      - name: CONSENSUS_SECRETS_PATH
+        value: /etc/consensus_secrets/.consensus_secrets.yaml
+```

docs/src/guides/advanced/README.md

@@ -20,6 +20,7 @@ way.
 - [ZK intuition](./13_zk_intuition.md)
 - [ZK deeper overview](./14_zk_deeper_overview.md)
 - [Prover keys](./15_prover_keys.md)
+- [Decentralization](./16_decentralization.md)
 
 Additionally, there are a few articles that cover specific topics that may be useful for developers actively working on
 `zksync-era` repo:

docs/src/guides/external-node/10_decentralization.md

@@ -28,7 +28,7 @@ Each participant node of the gossipnet has to have an identity (a public/secret
 the first time, generate the secrets by running:
 
 ```
-docker run --entrypoint /usr/bin/zksync_external_node "matterlabs/external-node:2.0-v24.12.0" generate-secrets > consensus_secrets.yaml
+docker run --entrypoint /usr/bin/zksync_external_node "matterlabs/external-node:2.0-v25.1.0" generate-secrets > consensus_secrets.yaml
 chmod 600 consensus_secrets.yaml
 ```