Look At Upgrading Postgres In Docker 
====================================

The standard Docker images for Postgres have the following issues wrt
in place upgrades:
- Only 1 version of Postgres binaries
- Cannot stop Postgres (stops container)

To get around this a custom image that has:
- 2 versions of Postgres binaries (e.g version 10 and 11)
- runs top (or tail -f etc) as its ENTRYPOINT so that Postgres is stopped

Run a container with this image using 2 volumes (one for the old install
one for the new);

$ docker run \
         --detach \
         --name=mig-postgres \
         --volume=/srv/docker/volumes/test-postgres/datadir10:/var/lib/postgresql/data \
         --volume=/srv/docker/volumes/test-postgres/datadir11:/var/lib/postgresql/data11 \ 
         migpostgres

$ docker exec -it mig-postgres bash
# chown postgres:postgres /var/lib/postgresql/data11
# su - postgres
postgres $ /usr/lib/postgresql/11/bin/initdb -D /var/lib/postgresql/data11
postgres $ /usr/lib/postgresql/11/bin/pg_upgrade \
           --old-bindir=/usr/lib/postgresql/10/bin \
           --new-bindir=/usr/lib/postgresql/11/bin \
           --old-datadir=/var/lib/postgresql/data \
           --new-datadir=/var/lib/postgresql/data11 \
           --old-port=5432 \
           --new-port=5433 \
           --check

(run again w/o --check if ok)

postgres $ echo "listen_addresses='*'" >> /var/lib/postgresql/data11/postgresql.conf 
postgres $ cp /var/lib/postgresql/data/pg_hba.conf \
              /var/lib/postgresql/data11
postgres $ exit
# exit

$ docker container stop mig-postgres
$ docker run \
         --detach \
         --name=test-postgres11 \
         --volume=/srv/docker/volumes/test-postgres/datadir11:/var/lib/postgresql/data \
         --publish 5432:5432 \
         postgres:11