18.2.2 Deploying Group Replication Locally

When you are following Section 18.2.1.2, “Configuring an Instance for Group Replication”, you need to add configuration for the data directories added in the previous section. For example:

[mysqld]

# server configuration
datadir=<full_path_to_data>/data/s1
basedir=<full_path_to_bin>/mysql-8.0/

port=24801
socket=<full_path_to_sock_dir>/s1.sock

These settings configure MySQL server to use the data directory created earlier and which port the server should open and start listening for incoming connections.

Group Replication requires a network connection between the members, which means that each member must be able to resolve the network address of all of the other members. For example in this tutorial all three instances run on one machine, so to ensure that the members can contact each other you could add a line to the option file such as report_host=127.0.0.1.

Then each member needs to be able to connect to the other members on their group_replication_local_address. For example in the option file of member s1 add:

group_replication_local_address= "127.0.0.1:24901"
group_replication_group_seeds= "127.0.0.1:24901,127.0.0.1:24902,127.0.0.1:24903"

This configures s1 to use port 24901 for internal group communication with seed members. For each server instance you want to add to the group, make these changes in the option file of the member. For each member you must ensure a unique address is specified, so use a unique port per instance for group_replication_local_address. Usually you want all members to be able to serve as seeds for members that are joining the group and have not got the transactions processed by the group. In this case, add all of the ports to group_replication_group_seeds as shown above.

The remaining steps of Section 18.2.1, “Deploying Group Replication in Single-Primary Mode” apply equally to a group which you have deployed locally in this way.