bitnami postgresql replaces postgresql.conf after restarting docker

Question

I'm using docker pull bitnami/postgresql:15.2.0 and I mount 2 directories:

• /bitnami/postgresql/data to /la/la/la/data
• /opt/bitnami/postgresql/conf to /la/la/la/conf

/opt/bitnami/postgresql/conf has postgresql.conf which I'm trying to change

After changing some values and restarting Docker the file has the default values back i.e. modified file replaced with the default conf file. It doesn't matter if Docker was running at the time of the change or not - I tried both ways.

I found the instructions on the site, but there are also a lot of questions about it. I don't understand how to use this:

Add your custom file to files/postgresql.conf in your working directory.

Apparently I'm doing something wrong ... so, do you guys have any advice on how to change postgresql.conf?

Thank you!

Answer 1

For simplicity, you can declare just the config you want to overwrite, then mount it onto opt/bitnami/postgresql/conf/conf.d/postgresql.conf.

For example I have this config file

➜  code cat postgresql.conf
log_connections = yes
shared_buffers = 128MB
log_min_messages=DEBUG5
log_min_error_statement=DEBUG

➜  code pwd
/Users/hoaphan/dev/code


➜  code docker run  --rm --name postgresql -ePOSTGRESQL_PASSWORD=123456 -v  /Users/hoaphan/dev/code/postgresql.conf:/opt/bitnami/postgresql/conf/conf.d/postgresql.conf bitnami/postgresql:15.2.0

You can verify that this is effective when compare the mount of logging:

with just (no config mounted)

docker run  --rm --name postgresql -ePOSTGRESQL_PASSWORD=123456 bitnami/postgresql:15.2.0 

---

Not recommended. But if for some reason you still want to override the full original config, you can:

• start the original container (eg: docker run --rm -it bitnami/postgresql:15.2.0 bash)

• copy the original config out onto your host(here I take the whole directory)

  docker cp postgresql:/opt/bitnami/postgresql/conf .

now after edited the conf/postgresql.con, I start another, overriding the full config: docker run --rm --name postgresql -ePOSTGRESQL_PASSWORD=123456 -v /Users/hoaphan/dev/code/conf/postgresql.conf:/opt/bitnami/postgresql/conf/postgresql.conf bitnami/postgresql:15.2.0

similar result, the config should be effective

---

Also if you postgres via binami helm chart:

helm repo add bitnami https://charts.bitnami.com/bitnami
helm install myrelease bitnami/postgresql

I'm pretty sure the https://docs.bitnami.com/kubernetes/infrastructure/postgresql/configuration/customize-config-file/ is BS from the look of https://charts.bitnami.com/bitnami/postgresql-12.4.2.tgz But you can add your config file using a values.yaml with content like:

primary:
  extendedConfiguration: |
    log_connections=yes
    log_min_messages=DEBUG5
    log_min_error_statement=DEBUG5

Then

helm install myrelease bitnami/postgresql --values values.yaml

will create ConfigMap like this and mount it into the running container as /opt/bitnami/postgresql/conf/conf.d/override.conf, postgres will know to pick it up and apply.

apiVersion: v1
data:
  override.conf: |-
    log_connections=yes
    log_min_messages=DEBUG5
    log_min_error_statement=DEBUG5
kind: ConfigMap
metadata:
  annotations:
    meta.helm.sh/release-name: myrelease
    meta.helm.sh/release-namespace: default
  creationTimestamp: "2023-05-03T09:13:58Z"
  labels:
    app.kubernetes.io/component: primary
    app.kubernetes.io/instance: myrelease
    app.kubernetes.io/managed-by: Helm
    app.kubernetes.io/name: postgresql
    helm.sh/chart: postgresql-12.4.2
  name: myrelease-postgresql-extended-configuration
  namespace: default