How to persist data in a dockerized postgres database using volumes

Question

My docker compose file has three containers  web  nginx  and postgres  Postgres looks like this  postgres    container name  postgres   restart  always   image  postgres latest   volumes      -   database  var lib postgresql   ports      - 5432 5432  My goal is to mount a volume which corresponds to a local folder called   database inside the postgres container as  var lib postgres  When I start these containers and insert data into postgres  I verify that  var lib postgres data base  is full of the data I m adding  in the postgres container   but in my local system    database only gets a data folder in it  i e    database data is created  but it s empty  Why  Notes   This suggests my above file should work  This person is using docker services which is interesting  UPDATE 1 Per Nick s suggestion  I did a docker inspect and found       quot Mounts quot                            quot Source quot    quot  Users alex Documents MyApp database quot                quot Destination quot    quot  var lib postgresql quot                quot Mode quot    quot rw quot                quot RW quot   true               quot Propagation quot    quot rprivate quot                                    quot Name quot    quot e5bf22471215db058127109053e72e0a423d97b05a2afb4824b411322efd2c35 quot                quot Source quot    quot  var lib docker volumes e5bf22471215db058127109053e72e0a423d97b05a2afb4824b411322efd2c35  data quot                quot Destination quot    quot  var lib postgresql data quot                quot Driver quot    quot local quot                quot Mode quot    quot  quot                quot RW quot   true               quot Propagation quot    quot  quot                    Which makes it seem like the data is being stolen by another volume I didn t code myself  Not sure why that is  Is the postgres image creating that volume for me  If so  is there some way to use that volume instead of the volume I m mounting when I restart  Otherwise  is there a good way of disabling that other volume and using my own    database  UPDATE 2 I found the solution  thanks to Nick   and another friend  Answer below

User · Answer

I would avoid using a relative path  Remember that docker is a daemon client relationship    When you are executing the compose  it s essentially just breaking down into various docker client commands  which are then passed to the daemon  That   database is then relative to the daemon  not the client   Now  the docker dev team has some back and forth on this issue  but the bottom line is it can have some unexpected results   In short  don t use a relative path  use an absolute path

User · Answer

You can create a common volume for all Postgres data  docker volume create pgdata  or you can set it to the compose file    version   quot 3 quot     services       db         image  postgres        environment           - POSTGRES USER postgres          - POSTGRES PASSWORD postgress          - POSTGRES DB postgres        ports           -  quot 5433 5432 quot         volumes           - pgdata  var lib postgresql data        networks           - suruse    volumes        pgdata   It will create volume name pgdata and mount this volume to container s path  You can inspect this volume docker volume inspect pgdata     output will be                  quot Driver quot    quot local quot            quot Labels quot                quot Mountpoint quot    quot  var lib docker volumes pgdata  data quot            quot Name quot    quot pgdata quot            quot Options quot                quot Scope quot    quot local quot

User · Answer

I think you just need to create your volume outside docker first with a docker create -v  location --name and then reuse it    And by the time I used to use docker a lot  it wasn t possible to use a static docker volume with dockerfile definition so my suggestion is to try the command line  eventually with a script

User · Answer

Strangely enough  the solution ended up being to change  volumes    -   postgres-data  var lib postgresql   to   volumes    -   postgres-data  var lib postgresql data

[postgresql] How to persist data in a dockerized postgres database using volumes

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