Docker Hive - /entrypoint.sh: line 4: pg_isready: command not found

Question

I have set up three containers that are networked because I would like to use Hadoop and Hive with PostgreSQL. You can access Docker set up via https://github.com/jcool12/hadoop-docker/tree/main/hivepost so you can download the folders/ files to run it. The Hadoop container works, the PostgreSQL container works, but the Hive container, upon startup, presents this error:

Waiting for PostgreSQL to start...
/entrypoint.sh: line 4: pg_isready: command not found

The PostgreSQL container is running and looks fine, yet I'm still encountering this error:

/entrypoint.sh: line 4: pg_isready: command not found.

I have installed the PostgreSQL client in the /hive/Dockerfile and modified the entrypoint.sh, but nothing resolves the error. Could you please help me resolve this issue?

Answer 1

Your existing setup actually seems to work for me. But perhaps you might consider moving the readiness check across to Docker Compose by updating your docker-compose.yml as follows:

version: '3.8'

services:    
  postgres:
    image: postgres:13
    environment:
      - POSTGRES_DB=hive
      - POSTGRES_USER=hiveuser
      - POSTGRES_PASSWORD=hivepassword
    healthcheck:
      test: ["CMD-SHELL", "pg_isready -d hive -U hiveuser"]
      interval: 5s
      timeout: 5s
      retries: 5

  hive:
    build: ./hive
    depends_on:
      postgres:
        condition: service_healthy

I have retained only the important bits for clarity.

1. Add healthcheck to the postgres service, which uses pg_isready and will only mark the container as healthy when it is ready to accept connections.
2. Add a condition to the depends_on for the hive service, so that it will only start once postgres has been marked as healthy.

You can then remove the pg_isready command from the entrypoint.sh file.