# What is MySQL Router?
MySQL Router is part of InnoDB cluster, and is lightweight middleware that
provides transparent routing between your application and back-end MySQL
Servers. It can be used for a wide variety of use cases, such as providing high
availability and scalability by effectively routing database traffic to
appropriate back-end MySQL Servers. The pluggable architecture also enables
developers to extend MySQL Router for custom use cases.
# Supported Tags and Respective Dockerfile Links
* MySQL Router 8.0, the latest GA bugfix release, for both x86 and AArch64(ARM64) architectures (tag: [`8.0`](https://github.com/mysql/mysql-docker/blob/main/mysql-router/8.0/Dockerfile)) ([mysql-router/8.0/Dockerfile](https://github.com/mysql/mysql-docker/blob/main/mysql-router/8.0/Dockerfile))
* MySQL Router 8.4, the LTS release, for both x86 and AArch64(ARM64) architectures (tag: [`latest`, `8.4`](https://github.com/mysql/mysql-docker/blob/main/mysql-router/8.4/Dockerfile)) ([mysql-router/8.4/Dockerfile](https://github.com/mysql/mysql-docker/blob/main/mysql-router/8.4/Dockerfile))
Images are updated when new MySQL Server maintenance releases and development milestones are published. Please note that non-GA releases are for preview purposes only and should not be used in production setups.
# How to Use the MySQL Router Images
The image currently uses the following mandatory variables:
| Variable | Description |
| ------------------------ | ------------------------------------------- |
| MYSQL_HOST | MySQL host to connect to |
| MYSQL_PORT | Port to use |
| MYSQL_USER | User to connect with |
| MYSQL_PASSWORD | Password to connect with |
Running in a container requires a working InnoDB cluster.
The image uses the following optional variables:
| Variable | Description |
| ------------------------ | ------------------------------------------- |
| MYSQL_INNODB_CLUSTER_MEMBERS | Wait for at least this number of cluster instances to be ONLINE |
| MYSQL_CREATE_ROUTER_USER | Whether to create a new account for the Router to use when it's running. Defaults to 1, set to 0 to disable. |
| MYSQL_ROUTER_BOOTSTRAP_EXTRA_OPTIONS | Additional command line options applied while bootstrapping |
If supplied the run script waits for the given mysql host to be up, the InnoDB cluster to have
MYSQL_INNODB_CLUSTER_MEMBERS members and then uses the given server for its
bootstrap mode
[Bootstrapping](https://dev.mysql.com/doc/mysql-router/en/mysql-router-deploying-bootstrapping.html).
The image can be run via:
```
docker run -e MYSQL_HOST=localhost -e MYSQL_PORT=3306 -e MYSQL_USER=mysql -e MYSQL_PASSWORD=mysql -e MYSQL_INNODB_CLUSTER_MEMBERS=3 -ti container-registry.oracle.com/mysql/community-router
```
It can be verified by typing:
```
docker ps
```
The following output should be displayed:
```
4954b1c80be1 mysql-router:8.0 "/run.sh mysqlrouter" About a minute ago Up About a minute (healthy) 6447/tcp, 6448/tcp, 0.0.0.0:6446->6446/tcp, 6449/tcp innodbcluster_mysql-router_1
```
# Exposed Ports
The following TCP ports are exposed by the MySQL Router container:
| Port | Description
| ----- | --------------------------------------------------------------------------------------- |
| 6446 | R/W connection port. Clients that connect to this port will be forwarded to the PRIMARY |
| 6447 | R/O connection port. Clients that connect to this port will be forwarded to a SECONDARY |
| 6448 | X Protocol R/W connection port. R/W port for X protocol client connections |
| 6449 | X Protocol R/O connection port. R/O port for X protocol client connections |
| 8443 | HTTPS REST interface port. |
For more information about the REST interface API, see:
https://dev.mysql.com/doc/mysql-router/en/mysql-router-rest-api-reference.html
For full usage documentation, see:
https://dev.mysql.com/doc/mysql-router/en/mysql-router-installation-docker.html