GitLab Scaling High Availability

In this repository you can see a simple and initial deploy of GitLab on docker-compose. The main idea was to deploy on swarm cluster.

You can easily configure and deploy your Docker-based GitLab installation in a swarm cluster.

Requirements

• Ubuntu >=18.04
• Docker
• Docker compose
• Docker Swarm

Install GitLab using docker-compose

1. Create a Docker-compose.yml : cd dockerCompose

2. Run docker-compose up

Setup a Docker swarm

There are a few things that we will need before we can get to Gitlab:

• A proxy to forward the requests to the correct services
• Postgres and Redis
• Prometheus to collect metrics from Gitlab and Grafana to visualize these metrics
• An NFS4 share to store any persistent data we need

The Proxy

Setting up NFS

1. First we need to install the NFS server: sudo apt install -y nfs-kernel-server
2. For the NFS share the will need a directory structure like the following:

.
+-- /srv/gitlab-swarm/
|   +-- gitlab 
        +-- config
        +-- data
        +-- logs
|   +-- grafana     
|   +-- postgres
|   +-- prometheus

We can create it using the following shell:

mkdir -p /srv/gitlab-swarm && \
mkdir -p /srv/gitlab-swarm/gitlab/{data,logs,config} && \
mkdir -p /srv/gitlab-swarm/postgres && \
mkdir -p /srv/gitlab-swarm/grafana && \
mkdir -p /srv/gitlab-swarm/prometheus && \
chmod -R 777 /srv/gitlab-swarm

3. Then we need to create the directory /exports/gitlab-swarm and mount srv/gitlab-swarm onto it (this is required for NFS version 4):

mkdir -p /exports/gitlab-swarm
mount --bind /srv/gitlab-swarm /exports/gitlab-swarm

4. Setup the NFS share by editing /etc/exports:

# /etc/exports

/exports/               *(rw,sync,fsid=0,crossmnt,no_subtree_check)
/exports/gitlab-swarm   *(rw,sync,no_root_squash,no_subtree_check)

5. Now we reload the NFS configuration: exportfs -ra

6. we need to add the following line to /etc/fstab: /srv/gitlab-swarm/ /exports/gitlab-swarm/ none bind

7. Remember that we need the NFS client installed on each node of the cluster: sudo apt install -y nfs-common

8. To test if the NFS configuration is correct, we can try mounting the share:

mkdir /var/tmp/test-nfs && \
mount -t nfs4 127.0.0.1:/gitlab-swarm /var/tmp/test-nfs && \
grep nfs4 /proc/mounts | cut -d ' ' -f 1,2,3 && \
umount /var/tmp/test-nfs

9. Running the commands above should output this: 127.0.0.1:/gitlab-swarm /var/tmp/test-nfs nfs4

Building the stack

1. Create the configuration files for the services we are deploying. The first one is for Gitlab itself (gitlab.rb).

2. The Prometheus configuration file to setup metrics collection from gitlab

3. The Grafana configuration file

Services

1. Now we can start defining the services of our stack. Let's begin with Gitlab itself: stack.yml

Deploying the stack

1. docker stack deploy -c stack.yaml gitlab

2. And if you access gitlab.localtest.me you get to our Gitlab instance running on Docker Swarm.

Authors

• Catarina Silva - catarinaacsilva

License

This project is licensed under the MIT License - see the LICENSE file for details