net_kernel:connect_node/1 returns ignored
Just some random thing I learnt today while playing with Erlang:
So, I was playing with connecting to another Erlang node; I’m thinking about how to use it for diagnostics. However, when I tried it…
1> net_kernel:connect_node('foo@roger-pc'). ignored
Huh? The documentation says:
Returns true if successful, false if not, and ignored if the local node is not alive.
Wait. What? Obviously the node is alive – I’m using it…? Hang on, maybe Erlang has a different meaning of “alive”?
2> erlang:is_alive(). false
Hmmm. Documentation again:
Returns true if the local node is alive; that is, if the node can be part of a distributed system. Otherwise, it returns false.
Ah. I didn’t give my local shell a name. Let’s try again:
$ erl -sname bar (bar@roger-pc)1>
Well, that’s more promising – there’s a name in the prompt…
(bar@roger-pc)1> is_alive(). true
(bar@roger-pc)2> net_kernel:connect_node('foo@roger-pc'). true