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ywn@ywn-virtual-machine:~/bitcoin/bin$ bitcoind -connect="18.214.92.184"
Error: Cannot obtain a lock on data directory /home/ywn/btc_data. Bitcoin Core is probably already running.
ywn@ywn-virtual-machine:~/bitcoin/bin$
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The bitcoin node I deployed is running, and I use “ bitcoind -connect="18.214.92.184" ” command to connect to the new node,
 but the above error occurs. what do I do?
I know that connect can be set via config file bitcoin.conf, but I want to set connect dynamically with command.




Ubuntu18
Bitcoin Core version v0.20.1

The default number of connections (nodes) Bitcoin Core works with is 125: 10 outbound and 115 inbound.

I use the command "bitcoin - maxconnections=300", and then I use the command "bitcoin cli getconnectioncount".
The output connectioncount is still 10. What should I do to achieve 15 outbound and 200 inbound connections?

Here are some questions about the node deployment of Bitcoin. I hope you can help me. Thanks.

Question 1
-connect=<ip>
       Connect only to the specified node; -noconnect disables automatic connections (the rules for this peer are the same as for -addnode). This option can be specified multiple times to connect to multiple nodes.

The above is a description of Bitcoin connection options. What is the maximum number of times the connection is used？in other words，How many nodes can a node connect at the same time？

Question 2
If I have an IP address of a node, can I obtain the IP addresses of all nodes connected to this node？