bitcoin-cli attempts to read the credentials from $HOME/.bitcoin. Since user2 will have a different home directory, bitcoin-cli will not able to find the credentials.
You can either symlink .bitcoin from user1's home directory to user2's, or alias bitcoin-cli for user2 to use -datadir=user1home/.bitcoin.
You may need to play around with the read ...
There is no need to resolve anything - some miners create arbitrary versions to attempt to speed up the mining process, as it gives them an additional field in the block block header to alter without having to recalculate the merkle root and other fields.
This is harmless, provided they aren't producing invalid blocks for version 2, in which case the block ...
In some cases, bitcoin-qt/bitcoind may regularly (and even gratuitously) flush the wallet , so it's possible that wallet.dat could be in an inconsistent state at the time you make your own copy.
The backupwallet RPC call should be a safe way to accomplish this.
I finally end up with this setting for my raspberry
content of the file bitcoind.service