Setup a Witness Backup Node

I will share my witness backup node story and some issues that I encountered.

Recently there was an issue of witness nodes among witnesses.
So @justyy shared his auto switching script.
https://github.com/DoctorLai/SteemWitnessAutoSwitch

The best way to handle the malfunction of the primary witness node is to manage backup witness nodes.

So I tried to setup my backup node. But I was not sure the detailed procedure.
I tried to find a proper tutorial to set it up, but I could not find any.

Here I share my trials with you.

1. Sync the block data
2. Create a new brain key for the backup node
3. Set the priv_wif_key in the config.ini
4. Run ./run.sh start

But I got this message from the steemd:

I found this post by @justyy regarding this message:
https://steemit.com/witness-category/@justyy/witness-category-a-backup-witness-node-added

Double singing is when you use the same private brain key on two active nodes at the same time. This will lead to double singing, which is extremely dangerous for the chain. You need to be 100% sure that your first node is dead to use the same brain key for your backup node.
This is why it is always better to have a separate brain key to use for your backup node.

I am sure that I used the different signing key for the backup node. I don't understand why I got this message.

Here is my guess.
I have not updated the new signing key because I don't want to switch my witness signing key. What I wanted is to prepare a backup node for the future failure of my primary node. If I updated the signing key, then the primary node cannot produce a block.

When my backup node tries to produce a block with 'etainclub' account whose signing key has not changed, it tried to get the priv_wif_key in the config.ini. So it failed since there is no the priv_wif_key of the primary node in the backup node.

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I checked whether or not I miss a block in the steem explorer.

I confirmed that I have not missed any block since the running of the backup node.

So It seems okay with the message. Please guide me if I am wrong.

Not producing block because I don't have the private key for STM5bJVcuxb4fzyKeXQ7nEBpcP4eHpDJvVuakWHdfCygf6Bq9NE2f

In case of the malfunction of the primary, I have to update the signing key of the backup node. It can be easily by the tool in the steemworld.

Posted through the ECblog app (https://blog.etain.club)