initial wrapper

Author: jphenow

Dockerfile

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+FROM percona/percona-postgresql-operator:2.6.0-ppg16.8-postgres
+
+# Create a custom entrypoint script that sets OOM score and starts postgres
+COPY entrypoint-wrapper.sh /usr/local/bin/
+RUN chmod +x /usr/local/bin/entrypoint-wrapper.sh
+
+# We don't change the original ENTRYPOINT - we wrap around it
+ENTRYPOINT ["/usr/local/bin/entrypoint-wrapper.sh"]

README.md

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+# OOM-Protected PostgreSQL Docker Image
+
+This Docker image extends `percona/percona-postgresql-operator:2.6.0-ppg16.8-postgres` with configurations to reduce the chances of PostgreSQL being killed by the Out-of-Memory (OOM) killer in Linux.
+
+## Features
+
+- Sets OOM score adjustment to `-900` for the Patroni process (which manages PostgreSQL)
+
+## How It Works
+
+This image works with the Percona PostgreSQL Operator architecture:
+
+1. Patroni is the process manager that starts and manages PostgreSQL
+2. Our wrapper script sets the OOM score adjustment to -1000 for the Patroni process
+3. This adjustment is inherited by PostgreSQL processes, protecting them from OOM killer
+4. Custom PostgreSQL configuration is provided to optimize memory usage
+5. The wrapper script preserves the original entrypoint behavior of the parent image
+
+## Usage
+
+### Basic Usage
+
+```bash
+docker build -t oom-protected-postgres .
+docker run -d --name postgres oom-protected-postgres
+```
+
+## References
+
+- [PostgreSQL documentation on kernel resources](https://www.postgresql.org/docs/current/kernel-resources.html)
+- [Percona blog on Out-of-Memory killer](https://www.percona.com/blog/out-of-memory-killer-or-savior/)
+- [Docker Hub: percona/percona-postgresql-operator](https://hub.docker.com/r/percona/percona-postgresql-operator)
+- [Patroni documentation](https://patroni.readthedocs.io/)

entrypoint-wrapper.sh

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+#!/bin/bash
+set -e
+
+# For Percona PostgreSQL Operator, Patroni is the process manager
+# The OOM score adjustment needs to be applied to Patroni process
+# which will then be inherited by the PostgreSQL process
+
+# Set OOM score adjustment to -1000 for the current process (Patroni)
+# This ensures both Patroni and PostgreSQL processes are killed last by the OOM killer
+if [ -f "/proc/self/oom_score_adj" ]; then
+    echo -900 > /proc/self/oom_score_adj
+    echo "Set OOM score adjustment to -1000 for Patroni process"
+else
+    echo "WARNING: Cannot set OOM score adjustment (file not found)"
+fi
+
+exec "$@"