I’m running containerized ManageIQ appliances for development.
To dump your postgres db running inside such a container you simply exec pg_dump.
In my case not directly, because pg_dump is a some obscure place inside the container.
docker exec miq_latest bash -lc 'pg_dump --format custom vmdb_production' > /tmp/pg_dump.pgdata
Start a vanilla postgres container to host your development db:
docker run --name miq_pg -e POSTGRES_USER=root -e POSTGRES_DB=vmdb_development -d -p 5432:5432 postgres:9.5
Now you can restore the dump
docker exec -i miq_pg pg_restore --dbname=vmdb_development --verbose --clean < /tmp/pg_dump.pgdata
Beware Mr. T
You might be used to run docker exec -ti - but don’t do this to dump a db. The -t, --tty flag
will also append a carriage return character.
❯ head /tmp/pg_dump.pgdata_dos | head -1 | cat -A
PGDMP^[email protected]^@M-r^M$
❯ head /tmp/pg_dump.pgdata | head -1 | cat -A
PGDMP^[email protected]^@M-r$
Better yet, pg_restore will just segfault on the wrong format
❯ docker exec -i miq_pg pg_restore --dbname=vmdb_development --verbose --clean < /tmp/pg_dump.pgdata_dos
❯ echo $?
139
❯ docker run --rm -ti --link=miq_pg -v /tmp:/tmp postgres:9.5 bash
root@9ce662730c82:/# pg_restore --dbname=vmdb_development --verbose --clean /tmp/pg_dump.pgdata_dos
Segmentation fault
