Docker Volumes Provisioner

hub.docker.com hasnat/volumes-provisioner

An alpine based helper image to essentially make directory with appropriate owner and permissions to be used by other containers. This is achieved by sed and install.

Most images require data folders to be under certain permissions, for mounted volumes directories have to be created and modified before container start. e.g.

• mysql data folder needs to be 1000:1000
• prometheus needs 65534:65534
• grafana needs 472:472

Config

Pass config as env var PROVISION_DIRECTORIES

uid:gid:mode:dir(s) e.g. 1000:1000:0755:/var/www

Can contain multiple directories separated by space and/or multiple configs separated by ;

e.g.

• 1000:1000:0755:/var/www/html
• 1000:1000:0755:/var/www /var/www/html
• 1000:1000:0755:/var/www /var/www/html;1001:1001:0755:/var/app /var/app/cache

draw

        PROVISION_DIRECTORIES                                                                              
                                                                                                           
                                                                                                           
                     sed                                                  -d, --directory                  
                                                                          treat all arguments as           
                                                                          directory names; create all      
                                                                          components of the specified      
                           ([0-9]+):([0-9]+):([0-9]+):([^:;]+);?          directories                      
                                │       │       │         │  │                                             
                                │       │       │         │  │            -o, --owner=OWNER                
                                │       │       │         │  │            set ownership (super-user only)  
                                └─────┐ └───┐   └─┐  ┌────┘  └────┐                                        
                                      │     │     │  │            │       -g, --group=GROUP                
                                      │     │     │  │            │       set group ownership, instead of  
                                      │     │     │  │            │       process' current group           
                                      ▼     ▼     ▼  ▼            ▼                                        
                       install -d -o \1 -g \2 -m \3 \4 ; ls -dhn \4 ;     -m, --mode=MODE                  
                                                                          set permission mode (as in       
                                                                          chmod), instead of rwxr-xr-x     
Examples                                                                                                   
                                                                                                           
PROVISION_DIRECTORIES: "1000:1000:0755:/var/www/html"                                                      
PROVISION_DIRECTORIES: "1000:1000:0755:/var/www /var/www/html"                                             
PROVISION_DIRECTORIES: "1000:1000:0755:/var/www /var/www/html;1000:1000:0755:/var/app /var/app/cache"      
PROVISION_DIRECTORIES: "65534:65534:0755:/var/data/prometheus/data"

Local Run example

docker run --rm \
-e PROVISION_DIRECTORIES=1000:1000:0755:/var/www \
-v `pwd`/data:/var/www \
hasnat/volumes-provisioner
ls -dhn data

Docker Compose prometheus example

Here using depends_on we make sure directory with correct permissions is created before prometheus starts

version: '2'
services:
  volumes-provisioner:
    image: hasnat/volumes-provisioner
    environment:
      PROVISION_DIRECTORIES: "65534:65534:0755:/var/data/prometheus/data"
    volumes:
      - "./var/data:/var/data"
    network_mode: none

  prometheus:
    image: prom/prometheus:v2.3.2
    ports:
      - "9090:9090"
    depends_on:
      - volumes-provisioner
    volumes:
      - "./var/data/prometheus/data:/prometheus/data"

Build locally

docker build -t volumes-provisioner .
docker run --rm \
-e PROVISION_DIRECTORIES=1000:1000:0755:/var/www \
-v `pwd`/data:/var/www \
volumes-provisioner
ls -dhn data

Notes

Won't work for docker for macos volume mounts