Frequent queries of status info

[LINGU2011-2012 (LINGU2)]

(08-07-2015 01:09 PM)LINGU2011-2012 (LINGU2) Wrote:  Executing remote commands to tbg15 with 1 ssh session, rather than 1 command 1 ssh session, helps. However, if commands are to the other 18 vpcs in class A internal ips, the ssh channels to them need to go thru the ssh channel of tbg15. This is not viable, especially true for real-time functions like dashboard (frequently executing top to all vpcs).
After a few successful executions, the ssh channels are blocked somehow. Of course, putting random delay between the executions help but is not scientific enough.
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Forget about it, it turns out to be a 'top | grep' problem due to different versions of 'top' installed on tbg15 and vpcs.
Still, some of them fail: "Error: (SSH) Channel open failure: open failed", which is from the nodejs ssh library.
In conclusion, with a persistent ssh channel to tbg15, frequent(period 10s)-and-low-load(top) commands can be executed on vpcs via temporary channels (ssh vpc-ip <command>) within the persistent ssh channel with some reliability.
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