# Bitnami Secure Image for Pgpool-II

## What is Pgpool-II?

> Pgpool-II is the PostgreSQL proxy. It stands between PostgreSQL servers and their clients providing connection pooling, load balancing, automated failover, and replication.

[Overview of Pgpool-II](https://pgpool.net/)
Trademarks: This software listing is packaged by Bitnami. The respective trademarks mentioned in the offering are owned by the respective companies, and use of them does not imply any affiliation or endorsement.

## TL;DR

### Docker Compose

```console
docker run --name pgpool bitnami/pgpool:latest
```

You can find the default credentials and available configuration options in the [Environment Variables](#environment-variables) section.

## Why use Bitnami Secure Images?

Those are hardened, minimal CVE images built and maintained by Bitnami. Bitnami Secure Images are based on the cloud-optimized, security-hardened enterprise [OS Photon Linux](https://vmware.github.io/photon/). Why choose BSI images?

- Hardened secure images of popular open source software with Near-Zero Vulnerabilities
- Vulnerability Triage & Prioritization with VEX Statements, KEV and EPSS Scores
- Compliance focus with FIPS, STIG, and air-gap options, including secure bill of materials (SBOM)
- Software supply chain provenance attestation through in-toto
- First class support for the internet’s favorite Helm charts

Each image comes with valuable security metadata. You can view the metadata in [our public catalog here](https://app-catalog.vmware.com/bitnami/apps). Note: Some data is only available with [commercial subscriptions to BSI](https://bitnami.com/).

![Alt text](https://github.com/bitnami/containers/blob/main/BSI%20UI%201.png?raw=true "Application details")
![Alt text](https://github.com/bitnami/containers/blob/main/BSI%20UI%202.png?raw=true "Packaging report")

If you are looking for our previous generation of images based on Debian Linux, please see the [Bitnami Legacy registry](https://hub.docker.com/u/bitnamilegacy).

## How to deploy Pgpool-II in Kubernetes?

Deploying Bitnami applications as Helm Charts is the easiest way to get started with our applications on Kubernetes. Read more about the installation in the [Bitnami PostgreSQL HA Chart GitHub repository](https://github.com/bitnami/charts/tree/master/bitnami/postgresql-ha).

## Why use a non-root container?

Non-root container images add an extra layer of security and are generally recommended for production environments. However, because they run as a non-root user, privileged tasks are typically off-limits. Learn more about non-root containers [in our docs](https://techdocs.broadcom.com/us/en/vmware-tanzu/application-catalog/tanzu-application-catalog/services/tac-doc/apps-tutorials-work-with-non-root-containers-index.html).

## Supported tags and respective `Dockerfile` links

Learn more about the Bitnami tagging policy and the difference between rolling tags and immutable tags [in our documentation page](https://techdocs.broadcom.com/us/en/vmware-tanzu/application-catalog/tanzu-application-catalog/services/tac-doc/apps-tutorials-understand-rolling-tags-containers-index.html).

## Get this image

The recommended way to get the Bitnami Pgpool-II Docker Image is to pull the prebuilt image from the [Docker Hub Registry](https://hub.docker.com/r/bitnami/pgpool).

```console
docker pull bitnami/pgpool:latest
```

To use a specific version, you can pull a versioned tag. You can view the [list of available versions](https://hub.docker.com/r/bitnami/pgpool/tags/) in the Docker Hub Registry.

```console
docker pull bitnami/pgpool:[TAG]
```

If you wish, you can also build the image yourself by cloning the repository, changing to the directory containing the Dockerfile and executing the `docker build` command. Remember to replace the `APP`, `VERSION` and `OPERATING-SYSTEM` path placeholders in the example command below with the correct values.

```console
git clone https://github.com/bitnami/containers.git
cd bitnami/APP/VERSION/OPERATING-SYSTEM
docker build -t bitnami/APP:latest .
```

## Using `docker-compose.yaml`

Please be aware this file has not undergone internal testing. Consequently, we advise its use exclusively for development or testing purposes.

## Connecting to other containers

Using [Docker container networking](https://docs.docker.com/engine/userguide/networking/), a different server running inside a container can easily be accessed by your application containers and vice-versa.

Containers attached to the same network can communicate with each other using the container name as the hostname.

## Configuration

### Initializing with custom scripts

**Everytime the container is started**, it will execute the files with extension `.sh` located at `/docker-entrypoint-initdb.d` after initializing Pgpool-II.

### Securing Pgpool-II traffic

Pgpool-II supports the encryption of connections using the SSL/TLS protocol. Should you desire to enable this optional feature, you may use the following environment variables to configure the application:

- `PGPOOL_ENABLE_TLS`: Whether to enable TLS for traffic or not. Defaults to `no`.
- `PGPOOL_TLS_CERT_FILE`: File containing the certificate file for the TLS traffic. No defaults.
- `PGPOOL_TLS_KEY_FILE`: File containing the key for certificate. No defaults.
- `PGPOOL_TLS_CA_FILE`: File containing the CA of the certificate. If provided, Pgpool-II will authenticate TLS/SSL clients by requesting them a certificate (see [ref](https://www.pgpool.net/docs/latest/en/html/runtime-ssl.html)). No defaults.
- `PGPOOL_TLS_PREFER_SERVER_CIPHERS`: Whether to use the server's TLS cipher preferences rather than the client's. Defaults to `yes`.

When enabling TLS, Pgpool-II will support both standard and encrypted traffic by default, but prefer the latter.

Alternatively, you may also provide this configuration in your [custom](https://github.com/bitnami/containers/blob/main/bitnami/pgpool#configuration-file) configuration file.

### Configuration file

You can override the default configuration by providing a configuration file. Set `PGPOOL_USER_CONF_FILE` with the path of the file, and this will be added to the default configuration.
You can also override the default hba configuration by providing a hba configuration file. Set `PGPOOL_USER_HBA_FILE` with the path of the file, and this will overwrite the default hba configuration.

Refer to the [server configuration](http://www.pgpool.net/docs/latest/en/html/runtime-config.html) manual for the complete list of configuration options.

### Re-attaching nodes

Pgpool-II does not reattach nodes automatically, to reattach a node you have to get the `id` of the node and then run the attach command manually.

#### Step 1: Get the node id

To get the node `id` first connect to the pgpool container and open a psql session:

```console
docker exec -it pgpool bash

PGPASSWORD=$PGPOOL_POSTGRES_PASSWORD psql -U $PGPOOL_POSTGRES_USERNAME -h localhost
```

and run: `show pool_nodes;`

```console
postgres=# show pool_nodes;
 node_id | hostname | port | status | lb_weight |  role   | select_cnt | load_balance_node | replication_delay | replication_state | replication_sync_state | last_status_change
---------+----------+------+--------+-----------+---------+------------+-------------------+-------------------+-------------------+------------------------+---------------------
 0       | pg-0     | 5432 | down     | 0.500000  | standby | 0          | true              | 0                 |                   |                        | 2020-07-09 15:50:41
 1       | pg-1     | 5432 | up       | 0.500000  | primary | 0          | false             | 0                 |                   |                        | 2020-07-09 15:48:31
(2 rows)
```

In this example pg-0 is the node we want to reattach, we will use node `0`.

#### Step 2: reattach the node

Now exit psql console and run the following command, `0` is the node id we got in the previous step.

```console
pcp_attach_node -h localhost -U $PGPOOL_ADMIN_USERNAME 0
```

This command will prompt for a password, this password is the one set in the environment variable: `PGPOOL_ADMIN_PASSWORD`

### Environment variables

#### Customizable environment variables

| Name                                     | Description                                                                                                                        | Default Value                       |
|------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------|-------------------------------------|
| `PGPOOL_WORK_DIR`                        | Pgpool-II working directory.                                                                                                       | `/tmp`                              |
| `PGPOOL_USER_CONF_FILE`                  | Custom Pgpool-II configuration file to be appended at Pgpool-II configuration file.                                                | `nil`                               |
| `PGPOOL_USER_HBA_FILE`                   | Custom Pgpool-II host-based authentication configuration to be appended to Pgpool-II host-based authentication configuration file. | `nil`                               |
| `PGPOOL_PASSWD_FILE`                     | Pgpool-II pool password file.                                                                                                      | `pool_passwd`                       |
| `PGPOOL_PORT_NUMBER`                     | Pgpool-II port number.                                                                                                             | `5432`                              |
| `PGPOOL_ENABLE_POOL_HBA`                 | Enable Pgpool-II host-based authentication.                                                                                        | `yes`                               |
| `PGPOOL_ENABLE_POOL_PASSWD`              | Enable Pgpool-II pool password.                                                                                                    | `yes`                               |
| `PGPOOL_ENABLE_LOAD_BALANCING`           | Enable Load-Balancing.                                                                                                             | `yes`                               |
| `PGPOOL_ENABLE_STATEMENT_LOAD_BALANCING` | Enable Statement Load-Balancing.                                                                                                   | `no`                                |
| `PGPOOL_DISABLE_LOAD_BALANCE_ON_WRITE`   | Disable Load-Balancing on write queries.                                                                                           | `transaction`                       |
| `PGPOOL_ENABLE_CONNECTION_CACHE`         | Enable Pgpool-II connection cache.                                                                                                 | `yes`                               |
| `PGPOOL_TIMEOUT`                         | Pgpool-II timeout (in seconds).                                                                                                    | `360`                               |
| `PGPOOL_CONNECT_TIMEOUT`                 | Pgpool-II connection timeout (in milliseconds).                                                                                    | `10000`                             |
| `PGPOOL_MAX_POOL`                        | Pgpool-II maximum number of cached connections.                                                                                    | `15`                                |
| `PGPOOL_HEALTH_CHECK_PERIOD`             | Pgpool-II Health Check period (in seconds).                                                                                        | `30`                                |
| `PGPOOL_HEALTH_CHECK_TIMEOUT`            | Pgpool-II Health Check timeout (in seconds).                                                                                       | `10`                                |
| `PGPOOL_HEALTH_CHECK_MAX_RETRIES`        | Pgpool-II Health Check max retries.                                                                                                | `5`                                 |
| `PGPOOL_HEALTH_CHECK_RETRY_DELAY`        | Pgpool-II Health Check retry delay (in seconds).                                                                                   | `5`                                 |
| `PGPOOL_HEALTH_CHECK_PSQL_TIMEOUT`       | Pgpool-II Health Check psql timeout (in seconds).                                                                                  | `15`                                |
| `PGPOOL_AUTO_FAILBACK`                   | Enable Pgpool-II auto_failback on false primaries detection.                                                                       | `no`                                |
| `PGPOOL_DISCARD_STATUS`                  | Discard Pgpool-II status file on restarts.                                                                                         | `yes`                               |
| `PGPOOL_SR_CHECK_USER`                   | Pgpool-II Streaming Replication Check username.                                                                                    | `nil`                               |
| `PGPOOL_SR_CHECK_PASSWORD`               | Pgpool-II Streaming Replication Check password.                                                                                    | `nil`                               |
| `PGPOOL_SR_CHECK_DATABASE`               | Pgpool-II Streaming Replication Check database.                                                                                    | `postgres`                          |
| `PGPOOL_SR_CHECK_PERIOD`                 | Pgpool-II Streaming Replication Check period (in seconds).                                                                         | `30`                                |
| `PGPOOL_HEALTH_CHECK_USER`               | Pgpool-II Health Check username.                                                                                                   | `$PGPOOL_SR_CHECK_USER`             |
| `PGPOOL_HEALTH_CHECK_PASSWORD`           | Pgpool-II Health Check password.                                                                                                   | `$PGPOOL_SR_CHECK_PASSWORD`         |
| `PGPOOL_ADMIN_USERNAME`                  | Pgpool-II Admin username.                                                                                                          | `nil`                               |
| `PGPOOL_ADMIN_PASSWORD`                  | Pgpool-II Admin password.                                                                                                          | `nil`                               |
| `PGPOOL_POSTGRES_USERNAME`               | PostgreSQL backend admin username.                                                                                                 | `postgres`                          |
| `PGPOOL_POSTGRES_PASSWORD`               | PostgreSQL backend admin password.                                                                                                 | `nil`                               |
| `PGPOOL_POSTGRES_CUSTOM_USERS`           | Comma, semi-colon or space separated list of custom users to create.                                                               | `nil`                               |
| `PGPOOL_POSTGRES_CUSTOM_PASSWORDS`       | Comma, semi-colon or space separated list of passwords for the custom users to create.                                             | `nil`                               |
| `PGPOOL_ENABLE_LDAP`                     | Enable LDAP on Pgpool-II.                                                                                                          | `no`                                |
| `PGPOOL_AUTHENTICATION_METHOD`           | Pgpool-II authentication method.                                                                                                   | `scram-sha-256`                     |
| `PGPOOL_AES_KEY`                         | Pgpool-II AES key.                                                                                                                 | `head -c 20 /dev/urandom \| base64` |
| `PGPOOL_ENABLE_TLS`                      | Enable TLS on Pgpool-II.                                                                                                           | `no`                                |
| `PGPOOL_TLS_CA_FILE`                     | Pgpool-II TLS authentication CA file.                                                                                              | `nil`                               |
| `PGPOOL_TLS_CERT_FILE`                   | Pgpool-II TLS authentication cert file.                                                                                            | `nil`                               |
| `PGPOOL_TLS_KEY_FILE`                    | Pgpool-II TLS authentication key file.                                                                                             | `nil`                               |
| `PGPOOL_TLS_PREFER_SERVER_CIPHERS`       | Prefer server TLS authentication ciphers.                                                                                          | `yes`                               |
| `PGPOOL_ENABLE_LOG_CONNECTIONS`          | Enable Pgpool-II log connections                                                                                                   | `no`                                |
| `PGPOOL_ENABLE_LOG_HOSTNAME`             | Show clients hostnames on Pgpool-II connections logs.                                                                              | `no`                                |
| `PGPOOL_ENABLE_LOG_PCP_PROCESSES`        | Enable PCP processes logging.                                                                                                      | `yes`                               |
| `PGPOOL_ENABLE_LOG_PER_NODE_STATEMENT`   | Enable logging every SQL statement for each DB node separately.                                                                    | `no`                                |
| `PGPOOL_BACKEND_NODES`                   | Comma, semi-colon or space separated list of PostgreSQL backend nodes.                                                             | `nil`                               |
| `PGPOOL_BACKEND_APPLICATION_NAMES`       | Comma, semi-colon or space separated list of PostgreSQL backend application names.                                                 | `nil`                               |
| `PGPOOL_FAILOVER_ON_BACKEND_SHUTDOWN`    | Enable failover recovery on backend shutdown.                                                                                      | `on`                                |
| `PGPOOL_FAILOVER_ON_BACKEND_ERROR`       | Enable failover recovery on backend error.                                                                                         | `off`                               |
| `PGPOOL_DAEMON_USER`                     | Pgpool-II daemon user                                                                                                              | `pgpool`                            |
| `PGPOOL_DAEMON_GROUP`                    | Pgpool-II daemon group                                                                                                             | `pgpool`                            |

#### Read-only environment variables

| Name                      | Description                                             | Value                              |
|---------------------------|---------------------------------------------------------|------------------------------------|
| `PGPOOL_BASE_DIR`         | Pgpool-II installation directory.                       | `${BITNAMI_ROOT_DIR}/pgpool`       |
| `PGPOOL_BIN_DIR`          | Pgpool-II binaries directory.                           | `${PGPOOL_BASE_DIR}/bin`           |
| `PGPOOL_DATA_DIR`         | Pgpool-II data directory.                               | `${PGPOOL_BASE_DIR}/data`          |
| `PGPOOL_DEFAULT_CONF_DIR` | Pgpool-II default configuration directory.              | `${PGPOOL_BASE_DIR}/conf.default`  |
| `PGPOOL_CONF_DIR`         | Pgpool-II configuration directory.                      | `${PGPOOL_BASE_DIR}/conf`          |
| `PGPOOL_DEFAULT_ETC_DIR`  | Pgpool-II default etc directory.                        | `${PGPOOL_BASE_DIR}/etc.default`   |
| `PGPOOL_ETC_DIR`          | Pgpool-II etc directory.                                | `${PGPOOL_BASE_DIR}/etc`           |
| `PGPOOL_LOG_DIR`          | Pgpool-II logs directory.                               | `${PGPOOL_BASE_DIR}/logs`          |
| `PGPOOL_TMP_DIR`          | Pgpool-II temporary directory.                          | `${PGPOOL_BASE_DIR}/tmp`           |
| `PGPOOL_INITSCRIPTS_DIR`  | Pgpool-II init scripts directory.                       | `/docker-entrypoint-initdb.d`      |
| `PGPOOL_CONF_FILE`        | Pgpool-II configuration file.                           | `${PGPOOL_CONF_DIR}/pgpool.conf`   |
| `PGPOOL_PCP_CONF_FILE`    | Performance Co-Pilot (PCP) configuration file.          | `${PGPOOL_ETC_DIR}/pcp.conf`       |
| `PGPOOL_PGHBA_FILE`       | Pgpool-II host-based authentication configuration file. | `${PGPOOL_CONF_DIR}/pool_hba.conf` |
| `PGPOOL_LOG_FILE`         | Pgpool-II log file.                                     | `${PGPOOL_LOG_DIR}/pgpool.log`     |
| `PGPOOL_PID_FILE`         | Pgpool-II pid file.                                     | `${PGPOOL_TMP_DIR}/pgpool.pid`     |
| `PGPOOLKEYFILE`           | Pgpool-II pool key file.                                | `${PGPOOL_CONF_DIR}/.pgpoolkey`    |

### FIPS configuration in Bitnami Secure Images

The Bitnami Pgpool-II Docker image from the [Bitnami Secure Images](https://go-vmware.broadcom.com/contact-us) catalog includes extra features and settings to configure the container with FIPS capabilities. You can configure the next environment variables:

- `OPENSSL_FIPS`: whether OpenSSL runs in FIPS mode or not. `yes` (default), `no`.

## Logging

The Bitnami Pgpool-II Docker image sends the container logs to `stdout`. To view the logs:

```console
docker logs pgpool
```

You can configure the containers [logging driver](https://docs.docker.com/engine/admin/logging/overview/) using the `--log-driver` option if you wish to consume the container logs differently. In the default configuration docker uses the `json-file` driver.

## Notable Changes

### 4.3.1-debian-10-r67

- The ENV `PGPOOL_AUTHENTICATION_METHOD` default value has been changed from `md5` to `scram-sha-256` as our `bitnami/postgresql-repmgr:latest` image now uses PSQL v14, which has `scram-sha-256` as the default auth method.

### 4.1.1-debian-10-r35

- The Pgpool container has been migrated to a "non-root" user approach. Previously the container ran as the `root` user and the Pgpool daemon was started as the `pgpool` user. From now on, both the container and the Pgpool daemon run as user `1001`. You can revert this behavior by changing `USER 1001` to `USER root` in the Dockerfile.
- No backwards compatibility issues are expected.
- Environment variables related to LDAP configuration were renamed removing the `PGPOOL_` prefix. For instance, to indicate the LDAP URI to use, you must set `LDAP_URI` instead of `PGPOOL_LDAP_URI`.

### 4.1.0-centos-7-r8

- `4.1.0-centos-7-r8` is considered the latest image based on CentOS.
- Standard supported distros: Debian & OEL.

## License

Copyright &copy; 2026 Broadcom. The term "Broadcom" refers to Broadcom Inc. and/or its subsidiaries.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

<http://www.apache.org/licenses/LICENSE-2.0>

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
