Postgresql 9.6 initdb fails in Centos 7 docker container

Question

I am trying to setup a docker image with Centos7 and PostgreSQL 9.6.

I use the centos:centos7 image as base, and I follow the steps from this page: https://wiki.postgresql.org/wiki/YUM_Installation

The step to initialize the DB

sh-4.2# /usr/pgsql-9.6/bin/postgresql96-setup initdb
Failed to get D-Bus connection: Operation not permitted
failed to find PGDATA setting in postgresql-9.6.service

I tried to follow these steps to enable systemd for the CentOS image, https://hub.docker.com/_/centos/ But it does not help.

I also tried to comment out the stmts in the postgresql96-setup script

#PGDATA=`systemctl show -p Environment "${SERVICE_NAME}.service" |
#                sed 's/^Environment=//' | tr ' ' '\n' |
#                sed -n 's/^PGDATA=//p' | tail -n 1`
#if [ x"$PGDATA" = x ]; then
#    echo "failed to find PGDATA setting in ${SERVICE_NAME}.service"
#    exit 1
#fi

Now the initdb works. But starting the service gives me the same error message

sh-4.2# systemctl enable postgresql-9.6.service
Created symlink from /etc/systemd/system/multi-user.target.wants/postgresql-9.6.service to /usr/lib/systemd/system/postgresql-9.6.service.
sh-4.2#  systemctl start postgresql-9.6.service
Failed to get D-Bus connection: Operation not permitted

Did I miss anything? Anyone can help me out of this?

Answer 1

The "D-Bus connection: Operation not permitted" is a hint that Postgres wants to talk to the SystemD daemon. I am running Postgres in a centos-7 docker container by using the https://github.com/gdraheim/docker-systemctl-replacement to avoid that situation.

Answer 2

The underlying problem is explained and can be resolved with this answer:

Failed to get D-Bus connection: Operation not permitted - Server Fault

You make your own new image ( centos7-systemd ) but it isn't as hard as it looks. But be careful to do exactly what it says, running your new image via:

docker run --privileged -ti -e container=docker -v /sys/fs/cgroup:/sys/fs/cgroup centos7-systemd /usr/sbin/init

and then connect to it via eg

$ sudo docker ps CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES 6667f8acbe5c centos7-systemd "/usr/sbin/init" 33 minutes ago Up 13 minutes eager_brattain $ docker exec -it eager_brattain bash

Then run those postgres instructions at https://wiki.postgresql.org/wiki/YUM_Installation and they will work fine.