How do you run one daemon for multiple users? I have installed Bitcoin v0.18.1 as user1.
Everything is fine, but now I need to let user2 access the same run so he can use bitcoin-cli as well.

However, once I log into the VM instance as user2 I get this error:

error: Could not locate RPC credentials. No authentication cookie could be found, and RPC password is not set.  See -rpcpassword and -stdinrpcpass.  Configuration file: (/home/user2/.bitcoin/bitcoin.conf)

It does not matter if the users use the same wallet, I just need bitcoin-cli to work for both users and use data from user1 (full sync)
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 permissions in either case.