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Description

When finding the warning "Unable to subscribe to AMB channel: /mid/server/<sys_id>", specially if the error is present with all the mid servers in the same Environment after an upgrade following a clone.

Agent log message will look like below:

2020-02-18 09:08:43 (019) StartupSequencer Initializing AMB client...
2020-02-18 09:08:43 (023) AMBClientProvider Connecting AMB client to instance...
...
2020-02-18 09:08:43 (796) StartupSequencer StartupSequencer: setting sysId: <sys_id>, command: sudo, password prompt: as default privileged command
...
2020-02-18 09:08:43 (930) AMBClientProvider WARNING *** WARNING *** Unable to subscribe to AMB channel: /mid/server/<sys_id>
...
2020-02-18 09:09:50 (264) ECCQueueMonitor.40 WARNING *** WARNING *** Reconnecting AMB channel..

And repeats again...

2020-02-18 09:09:50 (265) ECCQueueMonitor.40 Initializing AMB client...
2020-02-18 09:09:50 (272) AMBClientProvider Connecting AMB client to instance...

Release or Environment

  • Any release that uses AMB (Helsinki and later, which is when the AMB Channel was implemented).
  • This issue is related to the clone performed in the instance combined to the version upgrade of the MID server.

Cause

After a clone in the instance and upgrade. Once the MID server has upgraded accordingly the combination of a new upgraded version in the mid with an old key in the instance side made the issue appear.

Resolution

The solution to this issue is to rekey the MID server, using the steps described in Rekey a MID Server

Article Information

Last Updated:2020-06-05 00:36:50
Published:2020-02-20