Workshop Persistance Storage and Volume

$ docker run -d --name postgres_db -p 5432:5432 -v pg_data:/var/lib/postgresql/data postgres:10.1-alpine
$ docker ps
CONTAINER ID        IMAGE                  COMMAND                  CREATED             STATUS              PORTS                    NAMES
692828b21f0d        postgres:10.1-alpine   "docker-entrypoint..."   11 seconds ago      Up 13 seconds       0.0.0.0:5432->5432/tcp   postgres_db

$ psql -h localhost -p 5432 -U postgres
psql (10.1)
Type "help" for help.

postgres=#

or go inside the container (docker exec -it) interact with command line

$ docker exec -it 692828b21f0d  /bin/bash
bash-4.3# psql -U postgres
psql (10.1)
Type "help" for help.

postgres=#
postgres=# create database db1 with owner postgres;
CREATE DATABASE
postgres=# \q

inspect and test persistence of the volume

$ docker inspect 692828b21f0d
...
        "Mounts": [
            {
                "Type": "volume",
                "Name": "pg_data",
                "Source": "/var/lib/docker/volumes/pg_data/_data",
                "Destination": "/var/lib/postgresql/data",
                "Driver": "local",
                "Mode": "z",
                "RW": true,
                "Propagation": ""
            }
        ],
...

$ docker rm -f  692828b21f0d

$ docker run -d --name postgres_db2 -p 5432:5432 -v pg_data:/var/lib/postgresql/data postgres:10.1-alpine
abdf7976e35faf8c920128a6cfbeae82aff2f843e1e96313f3cb555586cb7f5f


$ docker exec -it abdf7976e35fa  bash
bash-4.3# psql -U postgres
psql (10.1)
Type "help" for help.

postgres=# show databases;
ERROR:  unrecognized configuration parameter "databases"
postgres=# \l
                                 List of databases
   Name    |  Owner   | Encoding |  Collate   |   Ctype    |   Access privileges
-----------+----------+----------+------------+------------+-----------------------
 db1       | postgres | UTF8     | en_US.utf8 | en_US.utf8 |
 postgres  | postgres | UTF8     | en_US.utf8 | en_US.utf8 |
 template0 | postgres | UTF8     | en_US.utf8 | en_US.utf8 | =c/postgres          +
           |          |          |            |            | postgres=CTc/postgres
 template1 | postgres | UTF8     | en_US.utf8 | en_US.utf8 | =c/postgres          +
           |          |          |            |            | postgres=CTc/postgres
(4 rows)

postgres=#

docker volume command

$ docker volume list
DRIVER              VOLUME NAME
local               pg_data

$ $ docker volume rm pg_data
Error response from daemon: unable to remove volume: 
remove pg_data: volume is in use - [abdf7976e35faf8c920128a6cfbeae82aff2f843e1e96313f3cb555586cb7f5f]

extra -e POSTGRES_PASSWORD=mysecretpassword

$ docker run -d --name postgres_db2 -p 5432:5432 -e POSTGRES_PASSWORD=mysecretpassword
 -v pg_data:/var/lib/postgresql/data postgres:10.1-alpine

location of linux file system for linux on mac

$ screen ~/Library/Containers/com.docker.docker/Data/com.docker.driver.amd64-linux/tty
# ls -ltrh /var/lib/docker/volumes/
total 28
drwxr-xr-x    3 root     root        4.0K Dec  3 14:37 pg_data
-rw-------    1 root     root       32.0K Dec  3 14:37 metadata.db