Connection to 127.0.0.1 refused in a Dockerfile based on postgres:17-alpine3.20
Good evening,
I am trying to create a Dockerfile for development purposes, which
would run Jetty and PostgreSQL. The PostgreSQL related part is below:
FROM postgres:17-alpine3.20
RUN apk update && apk upgrade && apk add --no-cache curl wget openjdk21 tini
# Tell docker-entrypoint.sh to create superuser "postgres"
# with password "mypassword" and database "postgres"
ENV POSTGRES_PASSWORD mypassword
# Tell docker-entrypoint.sh to change these params in postgresql.conf
ENV POSTGRES_INITDB_ARGS "--set port=6432 --set max_connections=20 --set
max_wal_size=2GB"
# The PostgreSQL port is changed from 5432 to 6432 to emulate pg_bouncer
ENV PGPORT 6432
ENV PGUSER words
ENV PGPASSWORD mypassword
WORKDIR /docker-entrypoint-initdb.d
COPY ["run-after-initdb.sh", "."]
RUN chmod +x run-after-initdb.sh && cat run-after-initdb.sh
USER postgres
EXPOSE 6432 9090
ENTRYPOINT ["/sbin/tini", "--"]
CMD ["sh", "-c", "docker-entrypoint.sh postgres & cd $JETTY_BASE && sleep
10 && java -Djdbc.drivers=org.postgresql.Driver -jar $JETTY_HOME/start.jar"]
And below is my run-after-initdb.sh script:
#!/bin/sh
createuser --username=postgres words
psql --username=postgres -c "GRANT USAGE ON SCHEMA public TO words;"
psql --username=postgres -c "ALTER USER words PASSWORD 'mypassword';"
for L in de en ru fr nl pl; do
createdb --username=postgres --owner=words words_$L
cd /dict/$L && psql words_$L < words_$L.sql
done
Then I build and run the docker image and that works without errors:
# docker build -t my_docker_image --progress=plain .
# docker run --name my_container -p 8080:8080 -p 6432:6432 my_docker_image
When I connect to the docker container via terminal,
I am able to connect with "psql words_de" command.
But the "psql -h localhost words_de" command fails:
psql: error: connection to server at "localhost" (127.0.0.1), port 6432
failed: Connection refused
Is the server running on that host and accepting TCP/IP connections?
connection to server at "localhost" (::1), port 6432 failed: Address not
available
Is the server running on that host and accepting TCP/IP connections?
I need the connection via 127.0.0.1 though,
because of my Java servlet hosted by the Jetty.
I have looked at the config files and env vars:
# ls -al /var/run/postgresql/
srwxrwxrwx 1 postgres postgres 0 Dec 1 19:06 .s.PGSQL.6432
-rw------- 1 postgres postgres 64 Dec 1 19:06 .s.PGSQL.6432.lock
# echo $PGDATA
/var/lib/postgresql/data
# grep -v '^#' $PGDATA/pg_hba.conf
local all all trust
host all all 127.0.0.1/32 trust
host all all ::1/128 trust
local replication all trust
host replication all 127.0.0.1/32 trust
host replication all ::1/128 trust
# grep -v '^.*#' $PGDATA/postgresql.conf
listen_addresses = '*'
max_wal_size = 2GB
min_wal_size = 80MB
log_timezone = UTC
datestyle = 'iso, mdy'
timezone = UTC
default_text_search_config = 'pg_catalog.english'
Is anybody able spotting, what am I doing wrong here? Thank you
TLDR "psql words_de" works, but "psql -h localhost words_de" does not
Best regards
Alex
Alexander Farber <alexander.farber@gmail.com> writes:
TLDR "psql words_de" works, but "psql -h localhost words_de" does not
I'd try connecting the first way and seeing what "show
listen_addresses" gives. Per your report it should be "*",
but maybe something is overriding that.
If it is "*", then it seems like something is interfering with
expanding that. Maybe try explicitly setting it to "localhost"?
regards, tom lane
Thank you, Tom -
On Sun, Dec 1, 2024 at 8:58 PM Tom Lane <tgl@sss.pgh.pa.us> wrote:
Alexander Farber <alexander.farber@gmail.com> writes:
TLDR "psql words_de" works, but "psql -h localhost words_de" does not
I'd try connecting the first way and seeing what "show
listen_addresses" gives. Per your report it should be "*",
but maybe something is overriding that.If it is "*", then it seems like something is interfering with
expanding that. Maybe try explicitly setting it to "localhost"?
it is empty in my docker container (but "localhost" on my prod server),
so I probably need to investigate that...
$ psql words_de
psql (17.2)
Type "help" for help.
words_de=> show listen_addresses;
listen_addresses
------------------
(1 row)
words_de=> set listen_addresses='localhost';
ERROR: parameter "listen_addresses" cannot be changed without restarting
the server
# grep listen_addresses $PGDATA/postgresql.conf
listen_addresses = '*'
I have tried changing the line in the Dockerfile, but it has not helped yet:
ENV POSTGRES_INITDB_ARGS "--set port=6432 --set max_connections=20 --set
max_wal_size=2GB --set listen_addresses=localhost"
ENV POSTGRES_INITDB_ARGS "--set port=6432 --set max_connections=20 --set
max_wal_size=2GB --set listen_addresses='localhost'"
Maybe the quotes get lost somehow when using the "--set" option?
$ grep listen $PGDATA/postgresql.conf
listen_addresses = localhost
My problem is related to
https://github.com/docker-library/postgres/pull/440/files
But I am yet not sure how to enable listening at localhost again
Alexander Farber <alexander.farber@gmail.com> writes:
it is empty in my docker container (but "localhost" on my prod server),
so I probably need to investigate that...
I'm betting the postgresql.conf entry is being overridden with a
postmaster command-line switch (not an initdb switch, which merely
sets up a postgresql.conf entry).
regards, tom lane
On 12/1/24 11:34, Alexander Farber wrote:
Good evening,
I am trying to create a Dockerfile for development purposes, which
would run Jetty and PostgreSQL. The PostgreSQL related part is below:
When I connect to the docker container via terminal,
I am able to connect with "psql words_de" command.
The terminal is in the container host?
If so does the host have an instance of Postgres running on it?
But the "psql -h localhost words_de" command fails:
Best regards
Alex
--
Adrian Klaver
adrian.klaver@aklaver.com
Seems too easy but have you tried
psql -p 6432 -h localhost words_de
?
On Sun, Dec 1, 2024 at 3:59 PM Alexander Farber <alexander.farber@gmail.com>
wrote:
Show quoted text
My problem is related to
https://github.com/docker-library/postgres/pull/440/filesBut I am yet not sure how to enable listening at localhost again
Yes thank you, I have tried specifying the port at the CLI too... that did
not help.
But restarting PostgreSQL in my
custom /docker-entrypoint-initdb.d/run-after-initdb.sh
has helped, even though I am not sure if it is the best way:
#!/bin/sh
LANGUAGES="de en fr nl pl ru"
createuser --username=postgres words
psql --username=postgres -c "GRANT USAGE ON SCHEMA public TO words;"
psql --username=postgres -c "ALTER USER words PASSWORD 'mypassword';"
for L in $LANGUAGES; do
createdb --username=postgres --owner=words words_$L
cd /dict/$L && psql words_$L < words_$L.sql
done
# Restart PostgreSQL to make it listen at localhost too
pg_ctl --options "-c listen_addresses='localhost'" --wait restart
Hi again, I would like to share a slightly better workaround
(does not restart PostgreSQL) for enabling localhost connections
(for example for servlets) in a postgres:17-alpine3.20 based Dockerfile:
RUN sed -i "s/listen_addresses=''/listen_addresses='localhost'/"
/usr/local/bin/docker-entrypoint.sh
Am Sonntag, dem 01.12.2024 um 21:59 +0100 schrieb Alexander Farber:
But I am yet not sure how to enable listening at localhost again
Instead of using a TCP/IP connection, why not use the unix socket to
connect to your database [1]https://jdbc.postgresql.org/documentation/use/#unix-sockets?
[1]: https://jdbc.postgresql.org/documentation/use/#unix-sockets
Thank you Torsten,
On Mon, Dec 2, 2024 at 12:32 PM Torsten Krah <krah.tm@gmail.com> wrote:
Am Sonntag, dem 01.12.2024 um 21:59 +0100 schrieb Alexander Farber:
But I am yet not sure how to enable listening at localhost again
Instead of using a TCP/IP connection, why not use the unix socket to
connect to your database [1]?[1] https://jdbc.postgresql.org/documentation/use/#unix-sockets
I will try that option too!
Is anybody able spotting, what am I doing wrong here? Thank you
Unless I'm mistaken, it seems like you are trying to run jetty and postgres
in the same container. You should really use two containers and run them
both with docker compose. Docker is very much designed to run a single
service. This should also greatly simplify your Dockerfile - you could
probably just use the vanilla postgres image for the postgres container.
Here's some info on how to achieve this:
https://www.docker.com/blog/how-to-use-the-postgres-docker-official-image/#Using-Docker-Compose