ERROR: The Compose file './docker-compose.yml' is invalid because: services.jenkins.volumes contains an invalid type, it should be an array

Question

The docker-compose file is like this:

version: '3'
services:
  jenkins:
    container_name: jenkins
    image: jenkins/jenkins
    ports:
      - "8080:8080"
    volumes:
      -$PWD/jenkins_home: /var/jenkins_home
    networks:
      - net
networks:
  net:

The docker version information:

Client: Docker Engine - Community
Version:           20.10.5
API version:       1.41
Go version:        go1.13.15
Git commit:        55c4c88
Built:             Tue Mar  2 20:33:55 2021
OS/Arch:           linux/amd64
Context:           default
Experimental:      true

Server: Docker Engine - Community
Engine:
 Version:          20.10.5
 API version:      1.41 (minimum version 1.12)
 Go version:       go1.13.15
 Git commit:       363e9a8
 Built:            Tue Mar  2 20:32:17 2021
 OS/Arch:          linux/amd64
 Experimental:     false
 containerd:
 Version:          1.4.4
 GitCommit:        05f951a3781f4f2c1911b05e61c160e9c30eaa8e
 runc:
 Version:          1.0.0-rc93
 GitCommit:        12644e614e25b05da6fd08a38ffa0cfe1903fdec
 docker-init:
 Version:          0.19.0
 GitCommit:        de40ad0

The error is:

The Compose file './docker-compose.yml' is invalid because: services.jenkins.volumes contains an invalid type, it should be an array

Answer 1

There should be a space between - and the value, and the value should be a string. See the docker compose volumes documentation .

version: '3'
services:
  jenkins:
    container_name: jenkins
    image: jenkins/jenkins
    ports:
      - "8080:8080"
    volumes:
      - "${PWD}/jenkins_home:/var/jenkins_home"
    networks:
      - net
networks:
  net:

Answer 2

You should add a space after - in docker-compose file. I also recommend using relative path instead of using PWD variable in docker-compose , so your file in volumes part would be like this:

volumes:
    - /path/to/jenkins_home:/var/jenkins_home

Or:

volumes:
    - jenkins_home:/var/jenkins_home

Also remember do not add space before or after :