RE: When I use an IOC in a container, streamDevice occasionally reports that protocol has been aborted, which causes the records in the IOC to become inaccessible from the host computer.

[Mark Rivers via Tech-talk <tech-talk at aps.anl.gov>]

Timeouts in the protocol should be recoverable.  From what I understand once this happens all CA access to the IOC is lost.  If so, this is a more serious issue.

 

Mark

 

 

From: Tech-talk <tech-talk-bounces at aps.anl.gov> On Behalf Of Zimoch Dirk via Tech-talk
Sent: Friday, May 12, 2023 2:16 PM
To: Wang, Andrew <wang126 at llnl.gov>
Cc: EPICS tech-talk <tech-talk at aps.anl.gov>
Subject: Re: When I use an IOC in a container, streamDevice occasionally reports that protocol has been aborted, which causes the records in the IOC to become inaccessible from the host computer.

 

Hi Andy,

 

I suspect your container stalls from time to time, causing timeouts in the protocol.

I do not think that containers have been designed with real-time performance in mind. Thus I am not really surprised that it does not behave like a pure host. Maybe you can tune how the host schedules the containers? Or reduce the number of containers per host? It may simply be overburdened. Do you have any figures on the system load?

Dirk

Am 12.05.2023 um 20:06 schrieb Wang, Andrew via Tech-talk <tech-talk at aps.anl.gov>:



Hi all,

 

I have created multiple IOCs for the project in which I am involved. They are all running in their own Docker container in a host computer running Ubuntu 20.04. In each Docker container, the following EPICs and support module versions are used.

 

1. EPICS: 7.0.4
2. StreamDevice: 2.8.15
3. Asyn: 4.41

 

In one of the IOCs, I have a SSEQ record that is used to push a scalar value to multiple records that set four parameters for the target instrument. There is an instance where streamDevice is unable to push the value to the second parameter, causing the protocol to abort. Then, a few minutes later, my colleagues and I have observed that no records from the IOC in question can be accessed through Channel Access. This is the error message that we receive.

 

Read operation timed out: some PV data was not read.

<RECORD_NAME> 0

CA.Client.Exception……………………………………………………..

Warning: “Virtual circuit disconnect”

Context: “op=0, channel=<RECORD_NAME>, type=DBR_TIME_DOUBLE, count=1, ctx=”<IP ADDRESS:PORT>”

Source File: ../getCopy.cpp line 91

Current Time: <TIME>

 

This also meant that I was unable to check the STAT field to see what the cause of the abortion was.

 

Thank you and I look forward to hearing back from everyone.

 

Andy

 

 

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