How do I mount a host directory as a volume in docker compose

Question

I have a development environment I m dockerizing and I would like the ability to livereload my changes without having to rebuild docker images  I m using docker compose because redis is one of my app s dependencies and I like being able to link a redis container I have two containers defined in my docker-compose yml  node    build    node   links      - redis   ports      -  quot 8080 quot    env file      - node-app env  redis    image  redis   ports      -  quot 6379 quot   I ve gotten to the point in my node app s dockerfile where I add a volume  but how do I mount the the host s directory in the volume so that all my live edits to the code are reflected in the container  Here s my current Dockerfile    Set the base image to Ubuntu FROM    node boron    File Author   Maintainer MAINTAINER Amin Shah Gilani  lt amin gilani me gt     Install nodemon RUN npm install -g nodemon    Add a  app volume VOLUME   quot  app quot      TODO  link the current   to  app    Define working directory WORKDIR  app    Run npm install RUN npm install    Expose port EXPOSE  8080    Run app using nodemon CMD   quot nodemon quot    quot  app app js quot    My project looks like this    - docker-compose yml - node-app env - node    - app js   - Dockerfile js

User · Answer

In docker-compose yml you can use this format  volumes      - host directory container directory  according to their documentation

User · Answer

There are a few options Short Syntax Using the host   guest format you can do any of the following   volumes      Just specify a path and let the Engine create a volume   -  var lib mysql      Specify an absolute path mapping   -  opt data  var lib mysql      Path on the host  relative to the Compose file   -   cache  tmp cache      User-relative path   -   configs  etc configs  ro      Named volume   - datavolume  var lib mysql  Long Syntax As of docker-compose v3 2 you can use long syntax which allows the configuration of additional fields that can be expressed in the short form such as mount type  volume  bind or tmpfs  and read only  version   quot 3 2 quot  services    web      image  nginx alpine     ports        -  quot 80 80 quot      volumes        - type  volume         source  mydata         target   data         volume            nocopy  true       - type  bind         source    static         target   opt app static  networks    webnet   volumes    mydata   Check out https   docs docker com compose compose-file  long-syntax-3 for more info

User · Answer

Checkout their documentation From the looks of it you could do the following on your docker-compose yml volumes      -     app  Where    is the host directory  and  app is the target directory for the containers   EDIT Previous documentation source now leads to version history  you ll have to select the version of compose you re using and look for the reference   For the lazy     v3   v2   v1 Side note  Syntax remains the same for all versions as of this edit

User · Answer

we have to create your own docker volume mapped with the host directory before we mention in the docker-compose yml as external 1 Create volume named share docker volume create --driver local   --opt type none   --opt device  home mukundhan share   --opt o bind share  2 Use it in your docker-compose version   quot 3 quot   volumes    share      external  true  services    workstation      container name   quot workstation quot      image   quot ubuntu quot      stdin open  true     tty  true     volumes        - share  share consistent       -   source  source consistent     working dir   source     ipc  host     privileged  true     shm size   2gb    db      container name   quot db quot      image   quot ubuntu quot      stdin open  true     tty  true     volumes        - share  share consistent     working dir   source     ipc  host  This way we can share the same directory with many services running in different containers

User · Answer

If you would like to mount a particular host directory   disk1 prometheus-data in the following example  as a volume in the volumes section of the Docker Compose YAML file  you can do it as below  e g   version   3   services    prometheus      image  prom prometheus     volumes        - prometheus-data  prometheus  volumes    prometheus-data      driver  local     driver opts        o  bind       type  none       device   disk1 prometheus-data  By the way  in prometheus s Dockerfile  You may find the VOLUME instruction as below  which marks it as holding externally mounted volumes from native host  etc   Note however  this instruction is not a must though to mount a volume into a container    Dockerfile     VOLUME   quot  prometheus quot        Refs   https   docs docker com compose compose-file  driver https   docs docker com compose compose-file  driver opts

User · Answer

It was two things  I added the volume in docker-compose yml  node    volumes      -   node  app  I moved the npm install  amp  amp  nodemon app js pieces into a CMD because RUN adds things to the Union File System  and my volume isn t part of UFS    Set the base image to Ubuntu FROM    node boron    File Author   Maintainer MAINTAINER Amin Shah Gilani  lt amin gilani me gt     Install nodemon RUN npm install -g nodemon    Add a  app volume VOLUME   quot  app quot      Define working directory WORKDIR  app    Expose port EXPOSE  8080    Run npm install CMD npm install  amp  amp  nodemon app js

[docker] How do I mount a host directory as a volume in docker compose

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