added tutorial for multikey

docs/validators/key-management/multikey-nodes.md

@@ -322,16 +322,219 @@ We strongly suggest to practice this process first on the public testnet. You sh
 :::
 
 Whenever deciding to switch from single-key operation to multikey, the following steps on how to execute this process can be considered:
-1. create your `allValidatorsKeys.pem` by manually (or through a text tool) concatenate all your `validatorKey.pem` files;
-2. start a multikey group, **configure it as a backup group**, provide the `allValidatorsKeys.pem` file to all the nodes forming the group;
-3. let this backup multikey group nodes sync and go the next step **after all these nodes are synced**;
-4. switch off your single-key backup nodes (if you previously had ones);
-5. create a new multikey group, configure it as main group and let it sync. **Do not provide the `allValidatorsKeys.pem` keys yet!**. Go the next step **after all these nodes are synced**; 
-6. after the main group nodes are synced, copy the `allValidatorsKeys.pem` file to all nodes from the main group, switch off the main single-key nodes and restart the multikey nodes from the main group, so they will load the `allValidatorsKeys.pem` file;
-7. closely monitor all your nodes in the explorer, should be online and with their rating status increasing/at 100%. Repeat this step for a few times at 10 minutes interval. 
+1. Create your `allValidatorsKeys.pem` by manually (or through a text tool) concatenate all your `validatorKey.pem` files;
+2. Start a multikey group, **configure it as a backup group**, provide the `allValidatorsKeys.pem` file to all the nodes forming the group;
+3. Let this backup multikey group nodes sync and go the next step **after all these nodes are synced**;
+4. Switch off your single-key backup nodes (if you previously had ones);
+5. Create a new multikey group, configure it as main group and let it sync. **Do not provide the `allValidatorsKeys.pem` keys yet!**. Go the next step **after all these nodes are synced**; 
+6. After the main group nodes are synced, copy the `allValidatorsKeys.pem` file to all nodes from the main group, switch off the main single-key nodes and restart the multikey nodes from the main group, so they will load the `allValidatorsKeys.pem` file;
+7. Closely monitor all your nodes in the explorer, should be online and with their rating status increasing/at 100%. Repeat this step for a few times at 10 minutes interval. 
 
 Make sure that all operations from step 6 are made as quickly as possible. In case this step takes a long time, the backup multikey group should take over.
 
 :::caution
 Always attempt this process while closely monitor your nodes. If done correctly, your nodes might experience a brief rating drop (until the backup group takes over - if necessary)
 :::
+
+### Setup a multikey node
+
+**1. Login as root & update/upgrade the machine**
+
+```
+bash
+apt-get update
+apt-get upgrade
+apt autoremove
+```
+
+**2. Add and configure the ubuntu user**
+
+```
+adduser ubuntu
+```
+
+Set a long password
+
+```
+usermod -aG sudo ubuntu
+echo 'StrictHostKeyChecking=no' >> /etc/ssh/ssh_config
+visudo
+```   
+
+Add this line:
+
+```
+ubuntu  ALL=(ALL) NOPASSWD:ALL
+```
+
+Save & exit
+
+```
+sudo su ubuntu
+sudo visudo -f /etc/sudoers.d/myOverrides
+```
+
+Add this line:
+
+```
+ubuntu  ALL=(ALL) NOPASSWD:ALL
+```
+
+Save & exit
+
+**3. Configure ssh service:**
+
+```
+cd
+mkdir .ssh && chmod 700 .ssh && cd .ssh/
+nano authorized_keys
+```
+
+Paste your pubkey & save & exit
+The pubkey can be obtained by typing `cat ~/.ssh/id_rsa.pub` (or the name of your key) 
+
+```
+chmod 600 authorized_keys
+```
+
+ssh config
+
+```
+sudo nano /etc/ssh/sshd_config
+```
+
+Uncomment & change this line to match your desired port:
+
+```
+Port <any port value > 1024> # example: 7728
+```
+
+Set the following fields to their respective values: 
+
+```
+#    PermitRootLogin -> no
+#    PubkeyAuthentication -> yes
+#    PasswordAuthentication -> no
+```
+
+Save & exit
+
+```
+sudo systemctl restart sshd
+```
+
+At this time a snapshot/image of the host could be generated using the provider’s accepted method. This snapshot/image could later be used to create/spin up further machines with all the initial setup already completed.
+
+
+**4. Configure your local ssh config file** 
+
+```
+nano ~/.ssh/config
+```
+
+Add:
+
+```
+Host host-0
+  Hostname xxx.yyy.zzz.ttt
+  User ubuntu
+  Port 7728
+  IdentityFile ~/.ssh/id_rsa
+```
+
+Save & exit
+
+
+**5. Keys Setup**
+
+```
+cd ~
+mkdir VALIDATOR_KEYS
+```
+
+Copy your validator(s) .pem file either by using scp:
+
+```
+scp allValidatorsKeys.pem ubuntu@xxx.yyy.zzz.xxx:/home/ubuntu/VALIDATOR_KEYS
+``` 
+
+Or by using nautilius file explorer:
+
+```
+sftp://host-0
+``` 
+
+
+**6. Node Setup**
+
+```
+git clone https://github.com/multiversx/mx-chain-scripts
+cd mx-chain-scripts/config/
+nano variables.cfg
+```
+
+Set the following:
+
+```
+#    ENVIRONMENT="mainnet"
+#    GITHUBTOKEN="<your github token>"
+#    NODE_EXTRA_FLAGS="" # optional for extra flags (example: `-log-save -profile-mode`)  
+#    OVERRIDE_CONFIGVER="" # optional for a particulare release (example: `rc-v1.6.0`)
+```
+
+Save & exit
+
+```
+cd ..
+./script.sh install
+```
+
+Install your node(s)
+You can tweak several binary flags settings by typing
+
+```
+sudo nano /etc/systemd/system/elrond-node-0.service
+```
+
+Save & exit
+Reload the service file:
+
+```
+sudo systemctl daemon-reload
+```
+
+For additional `prefs.toml` file settings adjustments, can use this:
+
+```
+nano ~/elrond-nodes/node-0/config/prefs.toml
+```
+
+Set the following:
+
+```
+#    DestinationShardAsObserver = "<shard ID>"
+#    NodeDisplayName = "node"
+#    Identity = "identity"
+#    RedundancyLevel = <redundancy level: 0 for main, 1 for first backup...>
+```
+
+```
+cp ~/VALIDATOR_KEYS/allValidatorsKeys.pem ~/elrond-nodes/node-0/config/
+cd ~/mx-chain-scripts
+./script.sh start
+```
+
+
+**7. Node Checkup**
+
+The running node can be monitored using the termui console
+
+```
+~/elrond-utils/termui -address 127.0.0.1:8080
+```
+
+If the node does not start in a reasonable time frame (5 minutes), we can check the log output by using this command:
+
+```
+sudo journalctl -f -u elrond-node-0.service
+```