Open GitLab using public-instance-ip of your instance. Then login using username as root and password as “instance-id”
Now, Click on the icon as shown in the below image to access the admin panel
Click on Applications
Select Mattermost and press edit button
Now, Replace the old ip with the public ip of your instance and Click on Submit
Copy the Application-ID and Secret in text file as we will need these details further in our setup.
In AWS Console, select the GitLab EC2 instance and SSH into the instance.
Enter the below Commands in the terminal
- sudo su
- nano /etc/gitlab/gitlab.rb
- Press ctrl+w and search for mattermost [gitlab-id]
- Now, edit and paste the mattermost [‘gitlab-id’] and mattermost [‘gitlab-secret’] that you have copied earlier in the step 6
- Press ctrl+x and then type y and enter to save
- Next, type the command gitlab-ctl reconfigure
Now open a new tab in the browser, enter public-ip of your instance with port 9000 to see Kanboard Admin Panel. URL : http://instance-public-ip:9000
You will see the login page , click on Sign In with Gitlab
Next, Click on Authorize
Your mattermost is integrated with GitLab and you can now select the default team or create your own team.

Steps to Integrate Mattermost with GitLab