Locale issue with en_GB.UTF-8

Hi All,

I am trying to use an extended image of PostgreSQL with en_GB.utf8 locale as explained in the
official docker documentation at https://hub.docker.com/r/_/postgres/

so my Dockerfile looks like

```
FROM postgres:10.3

RUN localedef -i en_GB -c -f UTF-8 -A /usr/share/locale/locale.alias en_GB.UTF-8

ENV LANG en_GB.utf8

ARG VERSION=7.4.1
LABEL maintainer="Citus Data https://citusdata.com" \
org.label-schema.name="Citus" \
org.label-schema.description="Scalable PostgreSQL for multi-tenant and real-time workloads" \
org.label-schema.url="https://www.citusdata.com" \
org.label-schema.vcs-url="https://github.com/citusdata/citus" \
org.label-schema.vendor="Citus Data, Inc." \
org.label-schema.version=${VERSION} \
org.label-schema.schema-version="1.0"

ENV CITUS_VERSION ${VERSION}.citus-1

# install Citus
RUN apt-get update \
&& apt-get install -y --no-install-recommends \
ca-certificates \
curl \
&& curl -s https://install.citusdata.com/community/deb.sh | bash \
&& apt-get install -y postgresql-$PG_MAJOR-citus-7.4=$CITUS_VERSION \
postgresql-$PG_MAJOR-hll=2.10.2.citus-1 \
postgresql-$PG_MAJOR-topn=2.0.2 \
&& apt-get purge -y --auto-remove curl \
&& rm -rf /var/lib/apt/lists/*

# add citus to default PostgreSQL config
RUN echo "shared_preload_libraries='citus'" >> /usr/share/postgresql/postgresql.conf.sample

# add scripts to run after initdb
COPY 000-configure-stats.sh 001-create-citus-extension.sql /docker-entrypoint-initdb.d/

# add health check script
COPY pg_healthcheck /

HEALTHCHECK --interval=4s --start-period=6s CMD ./pg_healthcheck

```

The modified image gets generated without any issues however, when I try to start the cluster the master container remains in an unhealthy state and never reaches healthy state. Following is the log for the issue.

```
master_1 | The files belonging to this database system will be owned by user "postgres".
master_1 | This user must also own the server process.
master_1 |
master_1 | The database cluster will be initialized with locale "en_GB.utf8".
master_1 | The default database encoding has accordingly been set to "UTF8".
master_1 | The default text search configuration will be set to "english".
master_1 |
master_1 | Data page checksums are disabled.
master_1 |
master_1 | fixing permissions on existing directory /var/lib/postgresql/data ... ok
master_1 | creating subdirectories ... ok
master_1 | selecting default max_connections ... 100
master_1 | selecting default shared_buffers ... 128MB
master_1 | selecting dynamic shared memory implementation ... posix
master_1 | creating configuration files ... ok
master_1 | running bootstrap script ... ok
master_1 | performing post-bootstrap initialization ... ok
master_1 |
master_1 | WARNING: enabling "trust" authentication for local connections
master_1 | You can change this by editing pg_hba.conf or using the option -A, or
master_1 | --auth-local and --auth-host, the next time you run initdb.
master_1 | syncing data to disk ... ok
master_1 |
master_1 | Success. You can now start the database server using:
master_1 |
master_1 | pg_ctl -D /var/lib/postgresql/data -l logfile start
master_1 |
master_1 | ****************************************************
master_1 | WARNING: No password has been set for the database.
master_1 | This will allow anyone with access to the
master_1 | Postgres port to access your database. In
master_1 | Docker's default configuration, this is
master_1 | effectively any other container on the same
master_1 | system.
master_1 |
master_1 | Use "-e POSTGRES_PASSWORD=password" to set
master_1 | it in "docker run".
master_1 | ****************************************************
master_1 | waiting for server to start....2018-07-13 09:06:44.614 UTC [89] LOG: number of prepared transactions has not been configured, overriding
master_1 | 2018-07-13 09:06:44.614 UTC [89] DETAIL: max_prepared_transactions is now set to 200
master_1 | 2018-07-13 09:06:44.659 UTC [89] LOG: listening on Unix socket "/var/run/postgresql/.s.PGSQL.5432"
master_1 | 2018-07-13 09:06:44.845 UTC [90] LOG: database system was shut down at 2018-07-13 09:06:17 UTC
master_1 | 2018-07-13 09:06:44.944 UTC [89] LOG: database system is ready to accept connections
master_1 | done
master_1 | server started
master_1 | ALTER ROLE
master_1 |
master_1 |
master_1 | /usr/local/bin/docker-entrypoint.sh: running /docker-entrypoint-initdb.d/000-configure-stats.sh
master_1 |
master_1 | /usr/local/bin/docker-entrypoint.sh: running /docker-entrypoint-initdb.d/001-create-citus-extension.sql
master_1 | BEGIN
master_1 | 2018-07-13 09:06:45.415 UTC [116] LOG: starting maintenance daemon on database 12995 user 10
master_1 | 2018-07-13 09:06:45.415 UTC [116] CONTEXT: Citus maintenance daemon for database 12995 user 10
master_1 | CREATE EXTENSION
master_1 | UPDATE 1
master_1 | COMMIT
master_1 |
master_1 |
**master_1 | 2018-07-13 09:06:47.293 UTC [89] LOG: received fast shutdown request
master_1 | waiting for server to shut down....2018-07-13 09:06:47.334 UTC [89] LOG: aborting any active transactions
master_1 | 2018-07-13 09:06:47.335 UTC [116] FATAL: terminating connection due to administrator command
master_1 | 2018-07-13 09:06:47.335 UTC [116] CONTEXT: Citus maintenance daemon for database 12995 user 10
master_1 | 2018-07-13 09:06:47.337 UTC [89] LOG: worker process: Citus Maintenance Daemon: 12995/10 (PID 116) exited with exit code 1
master_1 | 2018-07-13 09:06:47.339 UTC [89] LOG: worker process: logical replication launcher (PID 97) exited with exit code 1
master_1 | 2018-07-13 09:06:47.339 UTC [91] LOG: shutting down
master_1 | ...2018-07-13 09:06:50.597 UTC [89] LOG: database system is shut down
master_1 | done
master_1 | server stopped**
master_1 |
master_1 | PostgreSQL init process complete; ready for start up.
master_1 |
master_1 | 2018-07-13 09:06:50.668 UTC [1] LOG: number of prepared transactions has not been configured, overriding
master_1 | 2018-07-13 09:06:50.668 UTC [1] DETAIL: max_prepared_transactions is now set to 200
master_1 | 2018-07-13 09:06:50.668 UTC [1] LOG: listening on IPv4 address "0.0.0.0", port 5432
master_1 | 2018-07-13 09:06:50.668 UTC [1] LOG: listening on IPv6 address "::", port 5432
master_1 | 2018-07-13 09:06:50.728 UTC [1] LOG: listening on Unix socket "/var/run/postgresql/.s.PGSQL.5432"
master_1 | 2018-07-13 09:06:50.835 UTC [125] LOG: database system was shut down at 2018-07-13 09:06:50 UTC
master_1 | 2018-07-13 09:06:50.879 UTC [1] LOG: database system is ready to accept connections

```

I am simply unable to understand why this is happening as it is just a change in the LANG / encoding. Could someone form the developer/maintainer / user community shed some light on this ?

Also, if somebody can guide me how to use Citus with en_GB.utf8 support that would really be a big help.

Thanks

devopxy