Search Engine: Elastic

Article ID: 130533, created on Mar 28, 2017, last review on Mar 28, 2017

  • Applies to:
  • Operations Automation


An OA managed host is unreachable.

Many tasks, related to the host, are failing with the error:

Cannot establish connection to the host #NNN

There is an existing record in unreachable_hosts table of OA DB for the host with a large amount of failures:

plesk=> select * from unreachable_hosts ;
 host_id |       checked_at       | c_failures | last_response_delay
      35 | 2016-05-28 01:37:40+08 |        116 |                   1

OA Agent was down on the host, but got started back, which did not resolve the issue with tasks.


If slave node was unreachable for a long time, it does not become available right away after restart, because of a hardcoded timeout of unreachable hosts checking. The timeout becomes longer in proportion to the number of failed attempts to connect.


Wait more to have the OA Management Node reconnect to the slave host and recognize that it is available.

In case of time constraints, contact Odin Technical Support to restore the host connectivity instantly.

5356b422f65bdad1c3e9edca5d74a1ae caea8340e2d186a540518d08602aa065 e12cea1d47a3125d335d68e6d4e15e07

Email subscription for changes to this article
Save as PDF