Docker 2: Difference between revisions

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docker stop b0ff6611123e
docker stop b0ff6611123e
docker container rm b0ff6611123e
docker container rm b0ff6611123e
</syntaxhighlight>
=Networking with Docker Compose=
==General==
In order to connect on the network container to container I ended up setting up my own network.
<syntaxhighlight lang="bash">
docker network create --attachable django_demo
</syntaxhighlight>
Once we have the network we can assign the containers to the network by setting the network name and the network in this case django_demo
<syntaxhighlight lang="yaml">
version: '3.8'
services:
  django:
    container_name: djangoapp
    build:
      context: .
      dockerfile: Dockerfile
    command: 'python manage.py runserver 0.0.0.0:8000'
    ports:
      - 8000:8000
    volumes:
      - .:/app
    depends_on:
      - db
    networks:
      django_demo:
...
networks:
  django_demo:
    external: true     
</syntaxhighlight>
We need to specify the container_name because the default is to use the service name an, underscore and a number which in this case would have been django_1. This creates an invalid host as the underscore is not allowed.
==Commands==
We can see the network with
<syntaxhighlight lang="bash">
docker network inspect django_demo
</syntaxhighlight>
We can delete network with
<syntaxhighlight lang="bash">
docker network prune
</syntaxhighlight>
And we can see the containers with
<syntaxhighlight lang="bash">
docker ps
</syntaxhighlight>
==Django Specific==
===Allowed Hosts===
To ensure no errors we need to specify which hosts django allows. This is done in the settings.py. In this example the container name for the app is put in the allowed list.
<syntaxhighlight lang="python">
...
ALLOWED_HOSTS = ['127.0.0.1','djangoapp']
...
</syntaxhighlight>
===App Database Connection===
We need to also need to account for the hostname when using the container_name in the docker-compose yml
<syntaxhighlight lang="python">
DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.mysql',
        'NAME': 'dont',
        'USER': 'copy',
        'PASSWORD': 'this',
        'HOST': 'djangodb',
        'PORT': '3306'
    }
}
</syntaxhighlight>
==Flask==
===App Database Connection===
In this case I created a flask app so the database is specified in the main.py in the SQLALCHEMY_DATABASE_URI. Here we use the hostname for URI.
<syntaxhighlight lang="python">
app.config['SQLALCHEMY_DATABASE_URI'] = 'mysql://root:root@flaskdb/main'
</syntaxhighlight>
===Container to Container===
To call the django service we do this by using the hostname of the django service. In our case.
<syntaxhighlight lang="python">
...
  req = requests.get('http://djangoapp:8000/api/user')
  return jsonify(req.content.decode('utf-8'))
</syntaxhighlight>
</syntaxhighlight>

Revision as of 20:54, 16 August 2021

Build Container

RUN command

RUN su-exec volpara git clone https://github.com/bibble235/aports

Copying from on container

Given the container 

FROM ubuntu:18.04 AS opencv_build

Copying can be done using 

COPY --from=opencv_build /usr/local/opencv/ /usr/local/

Creating a docker postgres image

This exposes the default port 5432 for postgres 

docker run --name postgresq-spring -e POSTGRES_USER=iain -e POSTGRES_PASSWORD=password -p 5432:5432 -v /data:/var/lib/postgresql/data -d postgres:alpine

The -d is to run the container in the background
The postgres:alpine is the image name
The -p is the port to expose which is the default for postgress The -v is where the data will be stored

Running a Container

Sample for running a container with name test, ip 172,18.0.11, network to run on as billnet, capital P to expose the port (not for production), remove container when exit, it to have the errors go to the host console, and ps/dataservice for the image name 

 docker run --name test --ip=172,18.0.11 --net=billnet -P --rm -it ps/dataservice

Build MediaWiki Container

Build your own Docker Image

Get the definition from github and build the container. 

https://github.com/wikimedia/mediawiki-docker/blob/38d4e7f77f8b5b4efda91f969ccba2475fc2c597/1.35/apache/Dockerfile
docker build .

Use Prebuilt

We can install the prebuilt one with 

docker pull mediawiki


We can find the container with the command 

docker ps --format "table {{.ID}}\t{{.Status}}\t{{.Names}}"

b0ff6611123e   Up 2 minutes   some-mediawiki
898c8f40818d   Up 6 hours     k8s_operator_openshift-web...
b02230ae7074   Up 6 hours     k8s_kube-dns_kube-dns-qhbvf_....
ea19641bc9a1   Up 6 hours     k8s_webconsole_webconsole-...
0dc6ee563a9b   Up 6 hours     k8s_registry_docker-registry-...
0b6ea1064152   Up 6 hours     k8s_operator_openshift-servic...
...

From there we can get the ip address with 

docker inspect -f '{{range .NetworkSettings.Networks}}{{.IPAddress}}{{end}}' b0ff6611123e

172.17.0.9

Delete Container

We can stop the contain and delete it 

docker stop b0ff6611123e
docker container rm b0ff6611123e
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