Passing from manual Docker host network to Docker Compose bridge - docker

Question

I have 2 docker images a modbus server and a client which I run manually with docker run --network host server and the same with the client and work perfectly. But now I need to add them to a docker-compose file where the network is bridge, what I did like this:
autoserver:
image: 19mikel95/pymodmikel:autoserversynchub
container_name: autoserver
restart: unless-stopped
clientperf:
image: 19mikel95/pymodmikel:reloadcomp
container_name: clientperf
restart: unless-stopped
depends_on:
- autoserver
links:
- "autoserver:server"
And I read that to refer from a container to another one(client to server) I have to use the service name in the dockercompose YML (autoserver) so that is what I did. In the python file executed in the client(which is the performance.py from pymodbus) I changed 'localhost' to:
host = 'autoserver'
client = ModbusTcpClient(host, port=5020)
However I get this error:
[ERROR/MainProcess] failed to run test successfully Traceback (most
recent call last): File "performance.py", line 72, in
single_client_test
client.read_holding_registers(10, 1, unit=1)
File "/usr/lib/python3/dist-packages/pymodbus/client/common.py", line
114, in read_holding_registers
return self.execute(request) File "/usr/lib/python3/dist-packages/pymodbus/client/sync.py", line 107, in
execute
raise ConnectionException("Failed to connect[%s]" % (self.str())) pymodbus.exceptions.ConnectionException: Modbus
Error: [Connection] Failed to
connect[ModbusTcpClient(autoserver:5020)]
as asked, my full docker-compose YML is this:
version: '2.1'
networks:
monitor-net:
driver: bridge
volumes:
prometheus_data: {}
grafana_data: {}
services:
prometheus:
image: prom/prometheus:latest
container_name: prometheus
volumes:
- ./prometheus:/etc/prometheus
- prometheus_data:/prometheus
command:
- '--config.file=/etc/prometheus/prometheus.yml'
- '--storage.tsdb.path=/prometheus'
- '--web.console.libraries=/etc/prometheus/console_libraries'
- '--web.console.templates=/etc/prometheus/consoles'
- '--storage.tsdb.retention.time=200h'
- '--web.enable-lifecycle'
restart: unless-stopped
expose:
- 9090
networks:
- monitor-net
labels:
org.label-schema.group: "monitoring"
alertmanager:
image: prom/alertmanager:latest
container_name: alertmanager
volumes:
- ./alertmanager:/etc/alertmanager
command:
- '--config.file=/etc/alertmanager/config.yml'
- '--storage.path=/alertmanager'
restart: unless-stopped
expose:
- 9093
networks:
- monitor-net
labels:
org.label-schema.group: "monitoring"
nodeexporter:
image: prom/node-exporter:latest
container_name: nodeexporter
volumes:
- /proc:/host/proc:ro
- /sys:/host/sys:ro
- c:\:/rootfs:ro
command:
- '--path.procfs=/host/proc'
- '--path.rootfs=/rootfs'
- '--path.sysfs=/host/sys'
- '--collector.filesystem.ignored-mount-points=^/(sys|proc|dev|host|etc)($$|/)'
restart: unless-stopped
expose:
- 9100
networks:
- monitor-net
labels:
org.label-schema.group: "monitoring"
cadvisor:
image: gcr.io/google-containers/cadvisor:latest
container_name: cadvisor
volumes:
- c:\:/rootfs:ro
- /var/run:/var/run:rw
- /sys:/sys:ro
- /var/lib/docker:/var/lib/docker:ro
#- /cgroup:/cgroup:ro #doesn't work on MacOS only for Linux
restart: unless-stopped
expose:
- 8080
networks:
- monitor-net
labels:
org.label-schema.group: "monitoring"
grafana:
image: grafana/grafana:latest
container_name: grafana
volumes:
- grafana_data:/var/lib/grafana
- ./grafana/provisioning:/etc/grafana/provisioning
environment:
- GF_SECURITY_ADMIN_USER=${ADMIN_USER:-admin}
- GF_SECURITY_ADMIN_PASSWORD=${ADMIN_PASSWORD:-admin}
- GF_USERS_ALLOW_SIGN_UP=false
restart: unless-stopped
expose:
- 3000
networks:
- monitor-net
labels:
org.label-schema.group: "monitoring"
pushgateway:
image: prom/pushgateway:latest
container_name: pushgateway
restart: unless-stopped
expose:
- 9091
networks:
- monitor-net
labels:
org.label-schema.group: "monitoring"
caddy:
image: stefanprodan/caddy
container_name: caddy
ports:
- "3000:3000"
- "9090:9090"
- "9093:9093"
- "9091:9091"
volumes:
- ./caddy:/etc/caddy
environment:
- ADMIN_USER=${ADMIN_USER:-admin}
- ADMIN_PASSWORD=${ADMIN_PASSWORD:-admin}
restart: unless-stopped
networks:
- monitor-net
labels:
org.label-schema.group: "monitoring"
autoserver:
image: 19mikel95/pymodmikel:autoserversynchub
container_name: autoserver
ports:
- "5020:5020"
restart: unless-stopped
networks:
- monitor-net
clientperf:
image: 19mikel95/pymodmikel:reloadcomp
container_name: clientperf
restart: unless-stopped
networks:
- monitor-net
depends_on:
- autoserver
links:
- "autoserver:server"

Answer 1

The problem is in the StartTcpServer(context, identity=identity, address=("localhost", 5020)) of sincserver.py file from autoserver image. The localhost allows for TcpServer to accept connection only from localhost. It should be replaced with 0.0.0.0 in order to allow any external requests to this port.
The following Docker Compose shows it (sed -i 's|localhost|0.0.0.0|g' sincserver.py replaces the hostname):
version: '2.1'
services:
autoserver:
image: 19mikel95/pymodmikel:autoserversynchub
command: sh -c "
sed -i 's|localhost|0.0.0.0|g' sincserver.py;
python3 sincserver.py daemon off
"
ports:
- "5020:5020"
restart: unless-stopped
clientperf:
image: 19mikel95/pymodmikel:reloadcomp
restart: unless-stopped
depends_on:
- autoserver
Run:
docker-compose up -d
docker-compose logs -f clientperf
And you will see log like
clientperf_1 | [DEBUG/MainProcess] 574 requests/second
clientperf_1 | [DEBUG/MainProcess] time taken to complete 1000 cycle by 10 workers is 1.7410697999875993 seconds
clientperf_1 | [DEBUG/MainProcess] 692 requests/second
clientperf_1 | [DEBUG/MainProcess] time taken to complete 1000 cycle by 10 workers is 1.4434449000109453 seconds
clientperf_1 | [DEBUG/MainProcess] 708 requests/second
clientperf_1 | [DEBUG/MainProcess] time taken to complete 1000 cycle by 10 workers is 1.4116760999895632 seconds
clientperf_1 | [DEBUG/MainProcess] 890 requests/second
clientperf_1 | [DEBUG/MainProcess] time taken to complete 1000 cycle by 10 workers is 1.1230684999900404 seconds
clientperf_1 | [DEBUG/MainProcess] 803 requests/second
clientperf_1 | [DEBUG/MainProcess] time taken to complete 1000 cycle by 10 workers is 1.2450218999874778 seconds
clientperf_1 | [DEBUG/MainProcess] 753 requests/second
clientperf_1 | [DEBUG/MainProcess] time taken to complete 1000 cycle by 10 workers is 1.3274328999978025 seconds
clientperf_1 | [DEBUG/MainProcess] 609 requests/second
clientperf_1 | [DEBUG/MainProcess] time taken to complete 1000 cycle by 10 workers is 1.6399398999928962 seconds

Answer 2

You can try using the env variable like AUTO_SERVER_HOST and call this in your code
version: '2.1'
networks:
monitor-net:
driver: bridge
volumes:
prometheus_data: {}
grafana_data: {}
services:
prometheus:
image: prom/prometheus:latest
container_name: prometheus
volumes:
- ./prometheus:/etc/prometheus
- prometheus_data:/prometheus
command:
- '--config.file=/etc/prometheus/prometheus.yml'
- '--storage.tsdb.path=/prometheus'
- '--web.console.libraries=/etc/prometheus/console_libraries'
- '--web.console.templates=/etc/prometheus/consoles'
- '--storage.tsdb.retention.time=200h'
- '--web.enable-lifecycle'
restart: unless-stopped
expose:
- 9090
networks:
- monitor-net
labels:
org.label-schema.group: "monitoring"
alertmanager:
image: prom/alertmanager:latest
container_name: alertmanager
volumes:
- ./alertmanager:/etc/alertmanager
command:
- '--config.file=/etc/alertmanager/config.yml'
- '--storage.path=/alertmanager'
restart: unless-stopped
expose:
- 9093
networks:
- monitor-net
labels:
org.label-schema.group: "monitoring"
nodeexporter:
image: prom/node-exporter:latest
container_name: nodeexporter
volumes:
- /proc:/host/proc:ro
- /sys:/host/sys:ro
- c:\:/rootfs:ro
command:
- '--path.procfs=/host/proc'
- '--path.rootfs=/rootfs'
- '--path.sysfs=/host/sys'
- '--collector.filesystem.ignored-mount-points=^/(sys|proc|dev|host|etc)($$|/)'
restart: unless-stopped
expose:
- 9100
networks:
- monitor-net
labels:
org.label-schema.group: "monitoring"
cadvisor:
image: gcr.io/google-containers/cadvisor:latest
container_name: cadvisor
volumes:
- c:\:/rootfs:ro
- /var/run:/var/run:rw
- /sys:/sys:ro
- /var/lib/docker:/var/lib/docker:ro
#- /cgroup:/cgroup:ro #doesn't work on MacOS only for Linux
restart: unless-stopped
expose:
- 8080
networks:
- monitor-net
labels:
org.label-schema.group: "monitoring"
grafana:
image: grafana/grafana:latest
container_name: grafana
volumes:
- grafana_data:/var/lib/grafana
- ./grafana/provisioning:/etc/grafana/provisioning
environment:
- GF_SECURITY_ADMIN_USER=${ADMIN_USER:-admin}
- GF_SECURITY_ADMIN_PASSWORD=${ADMIN_PASSWORD:-admin}
- GF_USERS_ALLOW_SIGN_UP=false
restart: unless-stopped
expose:
- 3000
networks:
- monitor-net
labels:
org.label-schema.group: "monitoring"
pushgateway:
image: prom/pushgateway:latest
container_name: pushgateway
restart: unless-stopped
expose:
- 9091
networks:
- monitor-net
labels:
org.label-schema.group: "monitoring"
caddy:
image: stefanprodan/caddy
container_name: caddy
ports:
- "3000:3000"
- "9090:9090"
- "9093:9093"
- "9091:9091"
volumes:
- ./caddy:/etc/caddy
environment:
- ADMIN_USER=${ADMIN_USER:-admin}
- ADMIN_PASSWORD=${ADMIN_PASSWORD:-admin}
restart: unless-stopped
networks:
- monitor-net
labels:
org.label-schema.group: "monitoring"
autoserver:
image: 19mikel95/pymodmikel:autoserversynchub
container_name: autoserver
ports:
- "5020:5020"
restart: unless-stopped
networks:
- monitor-net
clientperf:
image: 19mikel95/pymodmikel:reloadcomp
container_name: clientperf
restart: unless-stopped
networks:
- monitor-net
depends_on:
- autoserver
environment:
- AUTO_SERVER_HOST=autoserver
Call env variable like below
host = os.environ['AUTO_SERVER_HOST']
client = ModbusTcpClient(host, port=5020)