engineervix/memcached-sasl repository overview

⁠Memcached with SASL Authentication

This is a custom Docker image for Memcached (based on this docker compose setup in the Zulip docs⁠), preconfigured to support SASL authentication using plain-text authentication. It automatically sets up the SASL configuration and password database at runtime.

I created it because I was trying to self-host Zulip via Dokku⁠, and couldn't find a decent way to configure Memcached as in the above setup, using the Official memcached plugin for dokku⁠.

⁠Features

• Memcached version 1.6.29-alpine
• SASL authentication enabled
• Custom environment variables for SASL configuration
• Automatically generates the SASL configuration file and user password database

⁠Usage

⁠Build the Image

1. Clone the repository to your local machine:

   git clone https://github.com/engineervix/docker-memcached-sasl.git
   cd memcached-sasl
   

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2. Build the Docker image:

   docker build -t your-dockerhub-username/memcached-sasl .
   

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3. Push the image to Docker Hub (or another container registry):

   docker push your-dockerhub-username/memcached-sasl
   

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⁠Environment Variables

The following environment variables can be configured when running the container:

• SASL_CONF_PATH: Path to the SASL configuration file (default: /home/memcache/memcached.conf).
• MEMCACHED_SASL_PWDB: Path to the SASL password database (default: /home/memcache/memcached-sasl-db).
• MEMCACHED_PASSWORD: Password used for the zulip user (default: "REPLACE_WITH_SECURE_MEMCACHED_PASSWORD").

⁠How It Works

1. The entrypoint script creates the SASL configuration file at the location specified by SASL_CONF_PATH. This file enables the plain-text mechanism for SASL authentication.

2. The script generates a password database file (MEMCACHED_SASL_PWDB), containing credentials for the user zulip. The username is set as zulip@localhost with the password defined by MEMCACHED_PASSWORD.

3. The memcached -S command starts Memcached with SASL authentication enabled, enforcing user authentication for all clients.

⁠Running the Image

You can run the image directly using Docker:

docker run -d \
  -e MEMCACHED_PASSWORD=your_secure_password \
  your-dockerhub-username/memcached-sasl

Or, use this image in a Dokku setup:

sudo dokku memcached:create memcached-zulip \
  --image "your-dockerhub-username/memcached-sasl" \
  --image-version "latest" \
  --custom-env "MEMCACHED_PASSWORD=your_secure_password"

⁠Customization

• If you want to customize the SASL mechanism or add more users, you can modify the Dockerfile or adjust the entrypoint script.
• For a more secure setup, ensure that the MEMCACHED_PASSWORD environment variable is set to a strong, random value.