How to save data using postgres docker image?

Question

I'm trying to save my data in / home / me / redmine so that when I stop my container, data loss. I am using the official postgres docker node image.

The problem is that every time I run the postgres container, it exits immediately. This problem occurred when I added "data" to / var / lib / postgresql, otherwise, without adding "data", it starts, but my data is not saved. Also, the path that I have on my host machine is / var / lib / postgresql / 9.4 / data, but the image page says that you need to use / var / lib / postgresql / data.

This is how I try to start / install the volume from the host:

docker run --name postgres -d \ --env='DB_NAME=redmine_production' \ --env='DB_USER=redmine' \ --env='DB_PASS=secret' \ --volume=/home/me/redmine/postgresql:/var/lib/postgresql/data \ postgres 

... and then after I linked redmine as follows ...

 docker run -d -p 3000:3000 --name redmine \ -v /home/me/redmine/files:/usr/src/redmine/files \ --link postgres:postgres redmine 

In the redmine container, the volume / home / me / redmine / files is a separate directory in which I try to save files other than those in the Postgres database.

Edit:

When I connect to the host / var / lib / postgresql directory, I find 9.4 / data in it, and then I see that the owner and group are not listed in my / etc / passwd or / etc / groups and wonder, it has no attitude to the problem.

 /var/lib/postgresql/9.4/data # ls -la total 88 drwx------ 18 70 70 4096 Aug 13 2015 . drwxr-xr-x 3 root root 4096 Mar 28 2015 .. drwx------ 8 70 70 4096 Jul 2 2015 base drwx------ 2 70 70 4096 Jul 2 2015 global drwx------ 2 70 70 4096 Mar 28 2015 pg_clog drwx------ 2 70 70 4096 Mar 28 2015 pg_dynshmem lrwxrwxrwx 1 root root 31 Mar 28 2015 pg_hba.conf -> /etc/postgresql- 9.4/pg_hba.conf lrwxrwxrwx 1 root root 33 Mar 28 2015 pg_ident.conf -> /etc/postgresql-9.4/pg_ident.conf drwx------ 4 70 70 4096 Mar 28 2015 pg_logical drwx------ 4 70 70 4096 Mar 28 2015 pg_multixact drwx------ 2 70 70 4096 Jul 2 2015 pg_notify drwx------ 2 70 70 4096 Mar 28 2015 pg_replslot drwx------ 2 70 70 4096 Mar 28 2015 pg_serial drwx------ 2 70 70 4096 Mar 28 2015 pg_snapshots drwx------ 2 70 70 4096 Aug 13 2015 pg_stat drwx------ 2 70 70 4096 Aug 13 2015 pg_stat_tmp drwx------ 2 70 70 4096 Mar 28 2015 pg_subtrans drwx------ 2 70 70 4096 Mar 28 2015 pg_tblspc drwx------ 2 70 70 4096 Mar 28 2015 pg_twophase -rw------- 1 70 70 4 Mar 28 2015 PG_VERSION drwx------ 3 70 70 4096 Mar 28 2015 pg_xlog -rw------- 1 70 70 88 Mar 28 2015 postgresql.auto.conf lrwxrwxrwx 1 root root 35 Mar 28 2015 postgresql.conf -> /etc/postgresql-9.4/postgresql.conf -rw------- 1 70 70 1626 Aug 13 2015 postmaster.log -rw------- 1 70 70 114 Jul 2 2015 postmaster.opts 

Thoughts?

Answer 1

Firstly, these environment variables look suspicious. Take a look at the documentation for the official Docker image and note that you need POSTGRES_DB , POSTGRES_USER and POSTGRES_PASSWORD , rather than DB_NAME , DB_USER and DB_PASS .

Also, you seem to be mostly on the right track. Here is a complete example:

First I launch the Postgres container. I host persistent storage somewhere outside of my home directory because, as you already noted, the files will not belong to you, which can be confusing in your home directory (although not necessarily problematic):

 docker run --rm --name postgres \ -v /tmp/postgres:/var/lib/postgresql/data \ -e POSTGRES_DB=larstest \ -e POSTGRES_USER=lars \ -e POSTGRES_PASSWORD=secret postgres 

Since this is the first time I started postgres pointing to this data directory, we will see that it initializes the database:

 The database cluster will be initialized with locale "en_US.utf8". The default database encoding has accordingly been set to "UTF8". The default text search configuration will be set to "english". Data page checksums are disabled. fixing permissions on existing directory /var/lib/postgresql/data ... ok creating subdirectories ... ok selecting default max_connections ... 100 selecting default shared_buffers ... 128MB selecting dynamic shared memory implementation ... posix creating configuration files ... ok running bootstrap script ... ok performing post-bootstrap initialization ... ok syncing data to disk ... ok Success. You can now start the database server using: 

Now, from another window, I can connect to it ...

 $ psql -h 172.17.0.4 -U lars larstest Password for user lars: psql (9.5.4, server 9.6.0) WARNING: psql major version 9.5, server major version 9.6. Some psql features might not work. Type "help" for help. 

... and create some data:

 larstest=# create table testtable (id integer); CREATE TABLE larstest=# insert into testtable values (1); INSERT 0 1 larstest=# select * from testtable; id ---- 1 (1 row) 

Now I exit the container:

 ^CLOG: received fast shutdown request LOG: aborting any active transactions FATAL: terminating connection due to administrator command LOG: autovacuum launcher shutting down LOG: shutting down LOG: database system is shut down 

We can verify that it no longer works:

 $ docker ps | grep postgres 

But if we run it again with the same command line arguments,

 docker run --rm --name postgres \ -v /tmp/postgres:/var/lib/postgresql/data \ -e POSTGRES_DB=larstest \ -e POSTGRES_USER=lars \ -e POSTGRES_PASSWORD=secret postgres 

We see that it does not initialize the database because it already exists, and skip directly:

 LOG: database system was shut down at 2016-10-21 03:13:50 UTC LOG: MultiXact member wraparound protections are now enabled LOG: database system is ready to accept connections LOG: autovacuum launcher started 

At this point, we can reconnect to the database and find that our data still exists:

 $ psql -h 172.17.0.2 -U lars larstest Password for user lars: psql (9.5.4, server 9.6.0) WARNING: psql major version 9.5, server major version 9.6. Some psql features might not work. Type "help" for help. larstest=# select * from testtable; id ---- 1 (1 row) 

That is almost all there is.