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POErlang: Cannot start slave - {error,timeout}
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copied!<p>I'm currently trying to set up a distributed Tsung load testing environment which uses the Erlang slave functionality, however I have been unsuccessful in getting the controller node to start a slave node. E.g.</p> <pre><code>(musicglue@load1)1> net:ping(musicglue@load2). pong (musicglue@load1)2> slave:start(load2,musicglue,"-setcookie tom"). {error,timeout} </code></pre> <h2>BACKGROUND</h2> <p>My env:</p> <p>Controller - hostname: load1, user: musicglue, Ubuntu 10.04 LTS, Erlang R15B01 compiled from source Slave - hostname: load2, user: musicglue, Ubuntu 10.04 LTS, Erlang R15B01 complied from source Firewall disabled SELinux not installed</p> <p>Things that are working:</p> <ul> <li>I can SSH from load1 onto load2 and vice versa</li> <li>I can start an erl sessions on load1 and load2</li> <li>I can start an erl session on load2 from load1; ssh load2 erl</li> <li>I can successfully ping load2 from load1 from an erl session using the same cookie on both nodes.</li> </ul> <p>Ping output:</p> <pre><code>musicglue@load1:~$ erl -rsh ssh -sname musicglue -setcookie tom Erlang R15B01 (erts-5.9.1) [source] [64-bit] [smp:4:4] [async-threads: 0] [hipe] [kernel-poll:false] Eshell V5.9.1 (abort with ^G) (musicglue@load1)1> net:ping(musicglue@load2). pong </code></pre> <h2>THE ISSUE</h2> <p>My problem occurs when attempting to start a slave session from load1 on load2:</p> <pre><code>musicglue@load1:~$ erl -rsh ssh -sname musicglue -setcookie tom Erlang R15B01 (erts-5.9.1) [source] [64-bit] [smp:4:4] [async-threads: 0] [hipe] [kernel-poll:false] Eshell V5.9.1 (abort with ^G) (musicglue@load1)1> net:ping(musicglue@load2). pong (musicglue@load1)2> slave:start(load2,musicglue,"-setcookie tom"). {error,timeout} </code></pre> <p>Here is the output I get from epmd when I run the slave:start command:</p> <pre><code>epmd: Thu May 24 10:01:57 2012: Non-local peer connected epmd: Thu May 24 10:01:57 2012: opening connection on file descriptor 4 epmd: Thu May 24 10:01:57 2012: got 12 bytes ***** 00000000 00 0a 7a 6d 75 73 69 63 67 6c 75 65 |..zmusicglue| epmd: Thu May 24 10:01:57 2012: ** got PORT2_REQ epmd: Thu May 24 10:01:57 2012: got 2 bytes ***** 00000000 77 01 |w.| epmd: Thu May 24 10:01:57 2012: ** sent PORT2_RESP (error) for "musicglue" epmd: Thu May 24 10:01:57 2012: closing connection on file descriptor 4 epmd: Thu May 24 10:01:57 2012: Local peer connected epmd: Thu May 24 10:01:57 2012: opening connection on file descriptor 4 epmd: Thu May 24 10:01:57 2012: got 24 bytes ***** 00000000 00 16 78 ca d6 4d 00 00 05 00 05 00 09 6d 75 73 |..x..M.......mus| ***** 00000010 69 63 67 6c 75 65 00 00 | icglue..| epmd: Thu May 24 10:01:57 2012: ** got ALIVE2_REQ epmd: Thu May 24 10:01:57 2012: registering 'musicglue:1', port 51926 epmd: Thu May 24 10:01:57 2012: type 77 proto 0 highvsn 5 lowvsn 5 epmd: Thu May 24 10:01:57 2012: got 4 bytes ***** 00000000 79 00 00 01 | y...| epmd: Thu May 24 10:01:57 2012: ** sent ALIVE2_RESP for "musicglue" epmd: Thu May 24 10:01:57 2012: unregistering 'musicglue:1', port 51926 epmd: Thu May 24 10:01:57 2012: closing connection on file descriptor 4 </code></pre> <p>Any help or suggestions anyone has would be much appreciated,</p> <p>Many thanks</p> <h2>EDIT</h2> <p>I should also mention that I can see the ssh connection being successfully acknowledged by load2 but then immediately disconnecting:</p> <pre><code>May 30 13:49:27 load2 sshd[16169]: Accepted publickey for musicglue from 173.45.236.182 port 51843 ssh2 May 30 13:49:27 load2 sshd[16171]: Received disconnect from 173.45.236.182: 11: disconnected by user </code></pre> <p>In response to below comments I have also tried to start the slave using different node names for the slave:</p> <pre><code>musicglue@load1:~$ erl -rsh ssh -sname musicglue -setcookie tom Erlang R15B01 (erts-5.9.1) [source] [64-bit] [smp:4:4] [async-threads:0] [hipe] [kernel-poll:false] Eshell V5.9.1 (abort with ^G) (musicglue@load1)1> slave:start(load2,bar,"-setcookie tom"). {error,timeout} </code></pre> <p>and for the controller:</p> <pre><code>musicglue@load1:~$ erl -rsh ssh -sname foo -setcookie tom Erlang R15B01 (erts-5.9.1) [source] [64-bit] [smp:4:4] [async-threads:0] [hipe] [kernel-poll:false] Eshell V5.9.1 (abort with ^G) (foo@load1)1> slave:start(load2,musicglue,"-setcookie tom"). {error,timeout} </code></pre> <p>and for both:</p> <pre><code>musicglue@load1:~$ erl -rsh ssh -sname foo -setcookie tom Erlang R15B01 (erts-5.9.1) [source] [64-bit] [smp:4:4] [async-threads:0] [hipe] [kernel-poll:false] Eshell V5.9.1 (abort with ^G) (foo@load1)1> slave:start(load2,bar,"-setcookie tom"). {error,timeout} </code></pre> <p>But to no avail</p> <h2>SOLUTION</h2> <p>Turns out that my problem was that my slave was unable to SSH onto the controller and therefore could not respond to any commands. </p> <p>After fixing this port of communication between the two nodes everyone worked perfectly.</p>

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