CODEWITHSUNDEEP
dockerdocker-composedockerfile
overexchange
overexchange

Reputation: 1

hostname attribute in docker-compose

In the below docker-compose file,

dbc:
  image: mysql:5.6
  hostname: db
  expose:
    - "3386"
  environment:
    MYSQL_DATABASE: somebackenddb
    MYSQL_USER: user1
    MYSQL_PASSWORD: pswd
    MYSQL_ROOT_PASSWORD: pswd

agent:
  image: somedockerhub/ansible
  volumes:
    - ../../whatever/x.yml:/whatever/y.yml
  links:
    - dbc
  environment:
    PROBE_HOST: "db"
    PROBE_PORT: "3306"

we are using hostname attribute in dbc service.

agent service is linked to that hostname whose value is db

Generally, hostnames are given to virtual machines.

Every container is given an IP address, but,

For a container launched by dbc service, what does hostname mean for a container?

Upvotes: 1

Views: 3982

Answers (1)

rokpoto.com
rokpoto.com

Reputation: 10736

By default hostnames of a docker container is equal to their container id.

Defining attribute hostname: db in docker-compose file will set hostname of dbc service container to be db.

If you enter the created container with docker exec -it [container_id] bash

and run command hostname you should see db.

Running hostname -i would show virtual ip address.

cat /etc/hosts would show: ... 172.17.0.4 db

Env. variable HOSTNAME insider container would equal db

Upvotes: 3

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