How to automatically get an available port? - docker

I'm working with docker containers for some projects and to save time i clone the docker composer file for my other projects.
The problem I have is that the ports for my mysql_database and apache_service are fixed values.
Example:
version: "3.2"
services:
apache_service:
build:
context: './docker/apache/'
links:
- mysql_service:mysql_service
depends_on:
- mysql_service
ports:
- "8080:80" # "random_port:80"
volumes:
- ./:/var/www/
mysql_service:
build:
context : ./
dockerfile : ./docker/mysql/Dockerfile
command: [
'--character-set-server=utf8mb4',
'--collation-server=utf8mb4_unicode_ci',
'--default-authentication-plugin=mysql_native_password',
]
restart:
always
volumes:
- ./docker/initdb:/docker-entrypoint-initdb.d
- ./docker/mysql/logs:/var/log/mysql
ports:
- "4306:3306" # "random_port:3306"
environment:
MYSQL_ROOT_PASSWORD: ${DB_PASSWORD}
container_name:
mysql_service
When i copy the docker-composer file and write docker-composer up i alwayas have to change the ports previously...
How i could automatily get an avaliable port for this services?

Use 0 as the host port: this way you will get the first available (random) port from the operating system; to later get the actual used port you can use the docker port <container> command.

Related

Docker Postgres database not running or accessible

Below is my Dockerfile:
FROM node:14
WORKDIR /workspace
COPY . .
COPY /prisma ./prisma/
RUN npm install
EXPOSE 3333
EXPOSE 9229
CMD [ "npm", "run", "start" ]
And my docker-compose.yml
version: '3.8'
services:
todoapp-api:
container_name: todoapp-api
build:
context: .
dockerfile: Dockerfile
ports:
- 3333:3333
postgres:
image: postgres:13.5
container_name: postgres
restart: always
environment:
- POSTGRES_USER=myuser
- POSTGRES_PASSWORD=mypassword
volumes:
- postgres:/var/lib/postgresql/data
ports:
- '5432:5432'
volumes:
postgres:
networks:
nestjs-crud:
And my .env:
DATABASE_URL="postgresql://myuser:mypassword#192.168.1.1/mydb?schema=public"
After struggling with making the database run and be accessible, I found out that one possible solution was to change the DATABASE_URL. As you can see, I am writing my IP Address there to get it to run and this works for me. However, when I replace 192.168.1.1 with the name of the service: postgres, it stops working and I get the error:
Can't reach database server at postgres:5432
Writing the IP address is not ideal of course. However, if I don't write the IP address then the database server just doesn't work.
I think you may need to atributte networks in the containers specs. You already defined what networks you have in the YAML but they need to be inserted in container's spec like
todoapp-api:
container_name: todoapp-api
networks:
- nestjs-crud
build:
context: .
dockerfile: Dockerfile
ports:
- 3333:3333
networks:
nestjs-crud:
internal: true
My recomendation is to create one network for the db and other for the API, then assing the network db for the db, and both in the API, thus, the API can acess db network. Than, you can acess the db by the host nestjs-crud.postgres
To bounce back, on the point of the comment above, the two services are not in the same network, which is why you have the concern. To solve this problem, it will be necessary to put the services in the same network by putting the mention:
networks:
- nestjs-crud
and depends_on in todoapp-api
in the todoapp-api and postgres service, this becomes:
version: '3.8'
services:
todoapp-api:
container_name: todoapp-api
build:
context: .
dockerfile: Dockerfile
ports:
- 3333:3333
networks:
- nestjs-crud
depends_on:
- postgres
postgres:
image: postgres:13.5
container_name: postgres
restart: always
environment:
- POSTGRES_USER=myuser
- POSTGRES_PASSWORD=mypassword
volumes:
- postgres:/var/lib/postgresql/data
ports:
- '5432:5432'
networks:
- nestjs-crud
volumes:
postgres:
networks:
nestjs-crud:
And add in .env database service name.

Update in-docker-compose container with new env_file

I have the following docker-compose configuration:
version: '2'
services:
nginx:
image: 'nginx:latest'
expose:
- '80'
- '8080'
container_name: nginx
ports:
- '80:80'
- '8080:8080'
volumes:
- '/home/ubuntu/nginx.conf:/etc/nginx/nginx.conf'
networks:
- default
restart: always
inmates:
image: 'xxx/inmates:mysql'
container_name: 'inmates'
expose:
- '3000'
env_file: './inmates.env'
volumes:
- inmates_documents_images:/data
- inmates_logs:/logs.log
networks:
- default
restart: always
we19:
image: 'xxx/we19:dev'
container_name: 'we19'
expose:
- '3000'
env_file: './we19.env'
volumes:
- we19_logs:/logs.log
networks:
- default
restart: always
desktop:
image: 'xxx/desktop:dev'
container_name: 'desktop'
expose:
- '3000'
env_file: './desktop.env'
volumes:
- desktop_logs:/logs.log
networks:
- default
restart: always
volumes:
inmates_documents_images:
inmates_logs:
desktop_logs:
we19_logs:
Assume I did docker-compose up -d --buiild.
Now the 4 containers (services) are runnig.
Now, I want to update ./desktop.env file with new content. Is there any possible way to reset only desktop container with the new env file? Or docker-compose restart is neccessary?
Basically I'm trying to restart only desktop container with the new env file but keep all 3 others container up running without restarting them.
Extract from docker-compose up --help
[...]
If there are existing containers for a service, and the service's configuration or image was changed after the container's creation, docker-compose up picks up the changes by stopping and recreating the containers (preserving mounted volumes). To prevent Compose from picking up changes, use the --no-recreate flag.
[...]
Usage: up [options] [--scale SERVICE=NUM...] [SERVICE...]
[...]
The following command should do the trick in your case.
docker-compose up -d desktop
If not, see the documentation for other options you can use to meet your exact requirement (e.g. --force-recreate, --renew-anon-volumes, ...)

Change default 0.0.0.0 from docker to specific

I've managed to run my docker container installing php / composer / phpmyadmin.
But as a result for example phpmyadmin is accessible through the url : http://0.0.0.0:8080/
How can I change the default 0.0.0.0 by something with more sense like http://myapp:8080
I guess I have to add something into my hosts; but I also guess I have to update my docker so he knew he has to read it.
Here is my docker-compose.yml
version: '3'
services:
symfony:
build:
context: .
dockerfile: docker/Dockerfile
image: project-manager
ports:
- 80:80
db:
image: mysql
ports:
- 3306:3306
volumes:
- "./.data/db:/var/lib/mysql"
environment:
MYSQL_ROOT_PASSWORD: root
phpmyadmin:
image: phpmyadmin/phpmyadmin
ports:
- "8080:80"
links:
- db
So actually 127.0.0.1 already respond as 0.0.0.0 listen to everything so as we just have to setup in the host what we need as usual. 127.0.0.1 myapp

Can't to connect to postgres container

I define postgres server in docker-compose.yml:
db:
image: postgres:9.5
expose:
- 5432
Then in another docker container I tried to connect to this postgres container. But it gives an error with warning:
Is the server running on host "db" (172.22.0.2) and accepting
data-service_1 | TCP/IP connections on port 5432?
Why container can't to connect to another by provided information (host="db" and port=5432)?
PS
Full docker-compose.yml:
version: "2"
services:
data-service:
build: .
depends_on:
- db
ports:
- "50051:50051"
db:
image: postgres:9.5
depends_on:
- data-volume
environment:
- POSTGRES_USER=cobrain
- POSTGRES_PASSWORD=a
- POSTGRES_DB=datasets
ports:
- "8000:5432"
expose:
- 5432
volumes_from:
- data-volume
# - container:postgres9.5-data
restart: always
data-volume:
image: busybox
command: echo "I'm data container"
volumes:
- /var/lib/postgresql/data
Solution #1. Same file.
To be able to access the db container, you have to define your other containers in context of docker-compose.yml. When containers are started, each container gets all other containers mapped in /etc/hosts.
Just do
version: '2'
services:
web:
image: your/image
db:
image: postgres:9.5
If you do not wish to put your other containers into the same docker-compose.yml, there are other solutions:
Solution #2. IP
Do docker inspect <name of your db container> and look for IPAddress directive in the result listing. Use that IPAddress as host to connect to.
Solution #3. Networks
Make your containers join same network. For that, under each service, define:
services:
db:
networks:
- myNetwork
Don't forget to change db for each container you are starting.
I usually go with the first solution during development. I use apache+php as one container and pgsql as another one, a separate DB for every project. I do not start more than one setting of docker-compose.yml, so in this case defining both containers in one .yml config is perfect.
the depends on is not correct. i would try to use other paramters like LINKS and environment:
version: "2"
services:
data-service:
build: .
links:
- db
ports:
- "50051:50051"
volumes_from: ["db"]
environment:
DATABASE_HOST: db
db:
image: postgres:9.5
environment:
- POSTGRES_USER=cobrain
- POSTGRES_PASSWORD=a
- POSTGRES_DB=datasets
ports:
- "8000:5432"
expose:
- 5432
#volumes_from:
#- data-volume
# - container:postgres9.5-data
restart: always
data-volume:
image: busybox
command: echo "I'm data container"
volumes:
- /var/lib/postgresql/data
this one works for me (not postgres but mysql)

connect to mysql database from docker container

I have this docker file and it is working as expected. I have php application that connects to mysql on localhost.
# cat Dockerfile
FROM tutum/lamp:latest
RUN rm -fr /app
ADD crm_220 /app/
ADD crmbox.sql /
ADD mysql-setup.sh /mysql-setup.sh
EXPOSE 80 3306
CMD ["/run.sh"]
When I tried to run the database as separate container, my php application is still pointing to localhost. When I connect to the "web" container, I am not able to connect to "mysql1" container.
# cat docker-compose.yml
web:
build: .
restart: always
volumes:
- .:/app/
ports:
- "8000:8000"
- "80:80"
links:
- mysql1:mysql
mysql1:
image: mysql:latest
volumes:
- "/var/lib/mysql:/var/lib/mysql"
ports:
- "3306:3306"
environment:
MYSQL_ROOT_PASSWORD: secretpass
How does my php application connect to mysql from another container?
This is similar to the question asked here...
Connect to mysql in a docker container from the host
I do not want to connect to mysql from host machine, I need to connect from another container.
At first you shouldn't expose mysql 3306 port if you not want to call it from host machine. At second links are deprecated now. You can use network instead. I not sure about compose v.1 but in v.2 all containers in common docker-compose file are in one network (more about networks) and can be resolved by name each other. Example of docker-compose v.2 file:
version: '2'
services:
web:
build: .
restart: always
volumes:
- .:/app/
ports:
- "8000:8000"
- "80:80"
mysql1:
image: mysql:latest
volumes:
- "/var/lib/mysql:/var/lib/mysql"
environment:
MYSQL_ROOT_PASSWORD: secretpass
With such configuration you can resolve mysql container by name mysql1 inside web container.
For me, the name resolutions is never happening. Here is my docker file, and I was hoping to connect from app host to mysql, where the name is mysql and passed as an env variable to the other container - DB_HOST=mysql
version: "2"
services:
app:
build:
context: ./
dockerfile: /src/main/docker/Dockerfile
image: crossblogs
environment:
- DB_HOST=mysql
- DB_PORT=3306
ports:
- 8080:8080
depends_on:
- mysql
mysql:
image: mysql:5.7.20
environment:
- MYSQL_USER=root
- MYSQL_ALLOW_EMPTY_PASSWORD=yes
- MYSQL_DATABASE=crossblogs
ports:
- 3306:3306
command: mysqld --lower_case_table_names=1 --skip-ssl --character_set_server=utf8 --explicit_defaults_for_timestamp

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