Re: How can I get a PV from an external server from inside a docker container?

[Florian Feldbauer via Tech-talk <tech-talk at aps.anl.gov>]

Title: Re: How can I get a PV from an external server from inside a docker container?

Hey,

just for completeness, if you know the IP addresses of all your IOCs you can also use the default docker network and set the Environment variables
EPICS_CA_AUTO_ADDR_LIST no
EPICS_CA_ADDR_LIST <list of all CA server IP addresses>

In this case, the udp broadcast part of CA seems to be omitted and CA checks the list of IPs directly.

At least this worked in my very first tests with containerization of our clients (Archiver, Alarm system, .....)
But of course this approach is rather error prone and you need to change your config every time an IP address changes/is being added.

On the other hand, this is the only way I know of if running docker in rootless mode.

Cheers,
Florian

Am 26.03.2024 um 09:59 schrieb Carsten Winkler via Tech-talk:

Hello Dale, hello Florian,

many thanks for your helpful advises. Now I could solve the issue simply by adding "network_mode: host" to the service "epicsbase".

Now my working docker-compose.yml  looks like:

services:
    epicsbase:
       image: softioc
       container_name: epicsbase
       volumes:
          - ./epicsbase/db:/usr/local/db
       working_dir: /usr/local/epics
       command:
          - /bin/sh
          - -c
          - |
          echo start first Soft IOC
          screen -d -m /usr/local/epics/epics-base/bin/linux-x86_64/softIoc -D /usr/local/epics/epics-base/dbd/softIoc.dbd -d /usr/local/db/test.db
          tail -f /dev/null # keep alive

       network_mode: host

Best regards
Carsten

--------------------Ursprüngliche Nachricht--------------------
Von: Carsten Winkler <carsten.winkler at helmholtz-berlin.de>
Gesendet: Montag 25. März 2024 14:55
An: tech-talk at aps.anl.gov
Betreff: How can I get a PV from an external server from inside a docker container?

Hello,

I have 3 SoftIOCs.
    1.) local host       = 193.100.100.100 with PV: "local_pv"
    2.) external host  = 192.200.200.200 with PV: "external_pv"
    3.) docker container    on local host   with PV: "docker_pv"

From local host I can read all PVs (caget local_pv external_pv docker_pv). 👍
From inside the docker container I can read the local_pv and the docker_pv
but not the external_pv. 🤔

Here is my docker compose configuration:

services:
    epicsbase:
       image: softioc
       container_name: epicsbase
       volumes:
          - ./epicsbase/db:/usr/local/db
       working_dir: /usr/local/epics
       command:
          - /bin/sh
          - -c
          - |
          echo start first Soft IOC
          screen -d -m /usr/local/epics/epics-base/bin/linux-x86_64/softIoc -D /usr/local/epics/epics-base/dbd/softIoc.dbd -d /usr/local/db/test.db
          tail -f /dev/null # keep alive
       networks:
          - ioc-net
networks:
    ioc-net:

From inside the docker container I have also already tried EPICS_CA_AUTO_ADDR_LIST / EPICS_CA_ADDR_LIST. Unfortunately without success.
With and without these environment variables I only get the local_pv and the docker_pv.

How can I also read the external_pv from inside the docker container?

Best regards
Carsten

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