Erlang Takeover After Successful Fault Tolerance
I have an application distributed across two nodes. When I stop () the first node the failover works fine, but (sometimes?) When I restart the first node the crash crashes and the app crashes as start_link comes back already running.
SUPERVISOR REPORT <0.60.0> 2009-05-20 12:12:01
===============================================================================
Reporting supervisor {local,twitter_server_supervisor}
Child process
errorContext start_error
reason {already_started,<2415.62.0>}
pid undefined
name tag1
start_function {twitter_server,start_link,[]}
restart_type permanent
shutdown 10000
child_type worker
ok
My app
start(_Type, Args)->
twitter_server_supervisor:start_link( Args ).
stop( _State )->
ok.
My director:
start_link( Args ) ->
supervisor:start_link( {local,?MODULE}, ?MODULE, Args ).
Both nodes use the same sys.config file.
What I don't understand about this process that the above shouldn't work?
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Your problem seems to be related to the Twitter server supervisor trying to start one of his children. Since the bug reports a child with start_function
{twitter_server,start_link,[]}
And since you are not showing this code, I can only assume that it is trying to register a name for itself, but a process with that name is already registered.
Even more guesswork, the reason shows Pid, Pid, which has a name that we tried to grab for ourselves:
{already_started,<2415.62.0>}
Pid has a non-zero seed, if it is zero, it means it is a local process. From which I conclude that you are trying to register a global name and you are connected to another node where there is already a global process registered with that name.
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