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MariaDB Replication MariaDB Replication

Stack

Databases

Asynchronous MariaDB replication: one primary accepts writes and streams its binary log to a read-only replica. This is the classic read-scaling / hot-standby topology.

Configuration

Type
Compose
Platform
linux
Env vars
MARIADB_DATABASE=appMARIADB_PASSWORD=''MARIADB_REPLICATION_PASSWORD=''MARIADB_REPLICATION_USER=replMARIADB_ROOT_PASSWORD=''MARIADB_USER=app
Source
Repo

Template by deployable-sh·Source

Report issue

Services

mariadb-primary

Configuration

Image
mariadb:11.8
Command
--log-bin,--server-id=1,--log-basename=primary
Ports
3306:3306
Volumes
/var/lib/mysql : primary-data
Env vars
MARIADB_ROOT_PASSWORD=${MARIADB_ROOT_PASSWORD}MARIADB_DATABASE=${MARIADB_DATABASE:-app}MARIADB_USER=${MARIADB_USER:-app}MARIADB_PASSWORD=${MARIADB_PASSWORD}MARIADB_REPLICATION_USER=${MARIADB_REPLICATION_USER:-repl}MARIADB_REPLICATION_PASSWORD=${MARIADB_REPLICATION_PASSWORD}
Restart
unless-stopped

Image details

Pulls: 3.2B
User: stackbrew
Created: Nov 25, 2014
Updated: 1 day ago
Status: active

mariadb-replica

Configuration

Image
mariadb:11.8
Command
--server-id=2,--read-only=ON
Ports
3307:3306
Volumes
/var/lib/mysql : replica-data
Env vars
MARIADB_ROOT_PASSWORD=${MARIADB_ROOT_PASSWORD}MARIADB_MASTER_HOST=mariadb-primaryMARIADB_REPLICATION_USER=${MARIADB_REPLICATION_USER:-repl}MARIADB_REPLICATION_PASSWORD=${MARIADB_REPLICATION_PASSWORD}
Restart
unless-stopped

Image details

Pulls: 3.2B
User: stackbrew
Created: Nov 25, 2014
Updated: 1 day ago
Status: active

Standalone Install

Select an install method, to see config/commands for deploying MariaDB Replication

Installation method

Install on Portainer

Import all app templates into your Portainer instance, for easy 1-click deploys

  1. Ensure both Docker and Portainer are installed, and up-to-date
  2. Log into your Portainer web UI
  3. Under Settings → App Templates, paste the below URL
  4. Head to Home → App Templates, and the list of apps will show up
  5. Select MariaDB Replication, fill in any config options, and hit Deploy

Template Import URL

https://raw.githubusercontent.com/Lissy93/portainer-templates/main/templates.json
Show Me demo
Original stackfile

The compose file this template deploys, straight from its repo:

name: mariadb-replication

services:
  mariadb-primary:
    image: mariadb:11.8
    restart: unless-stopped
    command: ["--log-bin", "--server-id=1", "--log-basename=primary"]
    environment:
      MARIADB_ROOT_PASSWORD: ${MARIADB_ROOT_PASSWORD}
      MARIADB_DATABASE: ${MARIADB_DATABASE:-app}
      MARIADB_USER: ${MARIADB_USER:-app}
      MARIADB_PASSWORD: ${MARIADB_PASSWORD}
      MARIADB_REPLICATION_USER: ${MARIADB_REPLICATION_USER:-repl}
      MARIADB_REPLICATION_PASSWORD: ${MARIADB_REPLICATION_PASSWORD}
    ports:
      - "3306:3306"
    volumes:
      - primary-data:/var/lib/mysql

  mariadb-replica:
    image: mariadb:11.8
    restart: unless-stopped
    command: ["--server-id=2", "--read-only=ON"]
    environment:
      MARIADB_ROOT_PASSWORD: ${MARIADB_ROOT_PASSWORD}
      MARIADB_MASTER_HOST: mariadb-primary
      MARIADB_REPLICATION_USER: ${MARIADB_REPLICATION_USER:-repl}
      MARIADB_REPLICATION_PASSWORD: ${MARIADB_REPLICATION_PASSWORD}
    ports:
      - "3307:3306"
    depends_on:
      - mariadb-primary
    volumes:
      - replica-data:/var/lib/mysql

volumes:
  primary-data:
  replica-data:

Or deploy it directly from the source:

git clone https://github.com/deployable-sh/stacks
cd stacks
docker compose -f mariadb-replication/compose.yaml up -d

More install options in our documentation.

Container Documentation

mariadb-primary Documentation

MariaDB Server is a high performing open source relational database, forked from MySQL.

mariadb-replica Documentation

MariaDB Server is a high performing open source relational database, forked from MySQL.

Serve MariaDB Replication on your own domain behind Caddy, Nginx or Traefik. Fill in your domain and copy the result. It's a starting point, some apps need their own base URL or extra headers set too.

Proxying mariadb-replication.example.com to http://mariadb-primary:3306

Add this to your Caddyfile

mariadb-replication.example.com {
	reverse_proxy http://mariadb-primary:3306
}

Check the logs first

Nine times out of ten the logs tell you exactly what went wrong.

  • In Portainer, go to Containers, click the container, then Logs. Or run docker logs <container>
  • Exit codes help too: 137 means killed, usually out of memory. 126 or 127 means the command inside the image is broken.

Port already in use

If deployment fails with "Bind for 0.0.0.0:3306 failed: port is already allocated", something else on your server is using that port.

  • Find what's using it: sudo ss -tlnp | grep :3306
  • Stop the other service, or pick a different host port. In 3306:3306 only the left number is yours to change, the right one belongs to the app.

Running but the page won't load

The container is up but nothing appears in your browser.

  • Use your server's real IP: http://your-server-ip:3306. The 0.0.0.0 link Portainer shows isn't a real address.
  • Give it a minute after first deploy, mariadb-replication can take a while to initialise.
  • Make sure your firewall allows the port, e.g. sudo ufw allow 3306

Image won't pull

Test the pull directly on the host: docker pull mariadb:11.8

  • "manifest unknown" means the tag no longer exists.
  • "toomanyrequests" is the Docker Hub rate limit. Log in with docker login to raise it.
  • "no space left on device" means a full disk. Reclaim space with docker system prune

"exec format error"

This means the image was built for a different CPU architecture than your server.

  • Check yours with uname -m: x86_64 is amd64, aarch64 is arm64. Raspberry Pi and other ARM boards are the usual culprits.

Container keeps restarting

The unless-stopped restart policy relaunches the app after every crash, so the real error can scroll past.

  • Check the logs right after a restart, the last few lines before it died are the useful ones.
  • Get the exit code with docker inspect <container> --format '{{.State.ExitCode}}'
  • Still stuck? Redeploy once with the restart policy set to no so the failure stays visible.

Stack won't deploy

Compose stacks fail fast on small mistakes, and Portainer shows the reason just above the editor.

  • YAML only accepts spaces for indentation, a single tab breaks the whole file.

Raise an issue

Found something which isn't working as it should? Here's how to report it.

A Compose stack

MariaDB Replication is a Compose stack, a set of containers (2 of them) defined in one file and brought up together by Portainer, then started and stopped as a single app.

The services

This stack is built from 2 containers that run side by side. Here's each one, with the image it runs and anything it waits for first:

  • mariadb-primary runs mariadb:11.8
  • mariadb-replica runs mariadb:11.8, starts after mariadb-primary

Ports

A port is the door the app answers on. A mapping like 3306:3306 means it's reachable on port 3306 of your server, where the left number is yours to change and the right one belongs to the app. It opens:

  • 3306:3306
  • 3307:3306

Volumes

A volume is where MariaDB Replication keeps its files so they survive an update or a restart. Without one, anything it saves would sit inside the container and vanish the moment it's recreated. This template mounts:

  • /var/lib/mysql kept in the primary-data volume Docker manages
  • /var/lib/mysql kept in the replica-data volume Docker manages

Environment variables

Environment variables are the settings you hand over when you deploy, things like a password or a timezone. MariaDB Replication takes 7 of them, all with defaults you can leave alone or tweak:

  • MARIADB_ROOT_PASSWORD, pulled from your own environment
  • MARIADB_DATABASE, defaults to app
  • MARIADB_USER, defaults to app
  • MARIADB_PASSWORD, pulled from your own environment
  • MARIADB_REPLICATION_USER, defaults to repl
  • MARIADB_REPLICATION_PASSWORD, pulled from your own environment
  • MARIADB_MASTER_HOST, defaults to mariadb-primary

Restart policy

The restart policy here is unless-stopped, so Docker restarts MariaDB Replication after a crash or reboot, but leaves it off when you stop it on purpose. You can change this on the deploy screen. The choices are no (never restart), on-failure (only after a crash), unless-stopped (restart unless you stop it), and always (bring it back no matter what).

Networking

Portainer puts these services on one shared private network, so they can find each other by name (like mariadb-primary) while only the ports above are open to you.

Platform

The platform is linux, the kind of system the container is built to run on. Docker and Portainer handle this on a normal Linux server.

Portainer app templates

Zooming out, this whole page comes from a Portainer app template: a short recipe telling Portainer how to set MariaDB Replication up. Add the template list to Portainer once, then deploying MariaDB Replication is a click rather than a wall of config.