Hi I know many people has requested that, but none of the solutions I found, could be applied on my case.
I guess there is a solution, but I cannot really find it! Basically I need to access a specific service running on my host machine from a docker container (dmz). I have a pool of docker containers and an " orchestrator" service that runs on the real machine (host). This guy is a python rest service running at port 5001 of the host and is responsible, for example, to save the execution logs of the running docker machines.
===============================================================
|1- HOST -> 5002:5002 dmz(dockerContainer):5002/service1 |
|2 - dmz <--> 9200:9200 elasticsearch:9200
|3- HOST:5002/service2 <- 5001:5001 dmz(dockerContainer) |
===============================================================
The connections 1 and 2 work. They are rest services and I get even the answer of the rest request. The 3 is what I need to do now, and I don’ t mange to! I don’ t know what happened, but I swear to god, three weeks ago from the containers I could access the host by its real IP address, and now I cannot anymore! I have no idea what has changed but just before I could and now I cannot anymore.
What I have tried up to now:
- 1- Instead of using the real IP use the docker0 172.17.0.1 (Docker Tip #65: Get Your Docker Host's IP Address from in a Container — Nick Janetakis)
- Does not work I get a connection timeout
Traceback (most recent call last):
File “/usr/local/lib/python3.6/site-packages/urllib3/connection.py”, line 157, in _new_conn
(self._dns_host, self.port), self.timeout, **extra_kw
File “/usr/local/lib/python3.6/site-packages/urllib3/util/connection.py”, line 84, in create_connection
raise err
File “/usr/local/lib/python3.6/site-packages/urllib3/util/connection.py”, line 74, in create_connection
sock.connect(sa)
TimeoutError: [Errno 110] Connection timed out
- 2 - Add extra_hosts on the dockerComposer.yml
extra_hosts: - "host:172.17.0.1"
- The same result from above!
- 3 - Add a external network (Docker compose, running containers in net:host - Stack Overflow)
hostnet: external: true name: host
- Apparently you cannot mix user defined and predefined networks, and I need both. The docker need to talk directly to other dockers via an internal virtual network.
ERROR: for testbed_dmz network-scoped alias is supported only for containers in user defined networks
ERROR: for dmz network-scoped alias is supported only for containers in user defined networks
ERROR: Encountered errors while bringing up the project.
- 4 - Port forwarding ( the thing I would prefer, but I guess I am too stupid to see a way to use)
Add a port for the host machine to the docker
ports: # 2 - DMZ ports - "127.0.0.1:5001:5001" - "5002:5002"
- Not a surprise that I can access the service on the docker (port 5002) from the host, but not the service on 5001 of the host from the docker. Well in fact I cannot even start the service. If I start the service, the docker network does not start, port in use, and vice versa if I put the docker before, I cannot start the service on the same port! YES, I know it is reasonable, but you cannot blame me for hopping to be able to do it ;). The thing is I don’ t know how to do it. How I could have a service that listens on the port of the host. I guess the port forwarding are mostly for communications on the sense HOST->Container, not in the other sens!
And now I am without options!!! Any Ideas, please 
- OS Version/build : Ubuntu 16.04
- Docker version : 19.03.2, build 6a30dfc
- Docker-compose version : 1.24.0, build 0aa59064
The original configurations, that could represent an interest dockerfile of the DMZ
#############################################################
# dockerfile
# DMZ dockerfile - Definition fo the DMZ server for the
# testbed. The DMZ is the machine that guarantees
# all the communication between the servers and the outside
# world are controlled.
#############################################################
FROM python:3.6
COPY . /app
WORKDIR /app
ENV PYTHONPATH "${PYTHONPATH}:.:.."
RUN pip install -r requirements.txt
ENTRYPOINT ["python3"]
CMD ["platform/testbed/restDMZServer.py"]
Composer file.
version: '3.5'
services:
dmz:
container_name: testbed_dmz
# 1 - DMZ image name
image: testbed_dmz:latest
ports:
# 2 - DMZ ports
- "5002:5002"
networks:
data_network:
# 3 - DMZ ip address
ipv4_address: 192.168.7.2
elasticsearch:
container_name: data_server
# 4 - Elasticsearch image name
image: docker.elastic.co/elasticsearch/elasticsearch:7.0.0
environment:
- cluster.name=docker-cluster
- bootstrap.memory_lock=true
- discovery.type=single-node
- "ES_JAVA_OPTS=-Xms512m -Xmx512m"
ulimits:
memlock:
soft: -1
hard: -1
ports:
- "9200:9200"
networks:
data_network:
# 5 elasticsearch ip address
ipv4_address: 192.168.7.3
kibana:
container_name: testbed_kibana
# 6 kibana image name
image: docker.elastic.co/kibana/kibana:7.0.0
environment:
# 7 again the elasticsearch ip address
- SERVER_NAME=192.168.7.3
ports:
- "5601:5601"
networks:
data_network:
# 8 kibana ip address
ipv4_address: 192.168.7.4
networks:
data_network:
# 9 the name of the network
name: DMZ_DATA_NET
driver: bridge
ipam:
driver: default
config:
# 10 the network address
- subnet: 192.12.7.0/29