GitLab in Kubernetes

🐲

kmorton1988

Difficulty: Hard / Advanced

Introduction

In this article, I will describe all the steps required to set up GitLab in Kubernetes using Kustomize. We will go through how to run GitLab on Kubernetes when you already have related resources, such as Postgres, Redis, MinIO, and TLS Certificates, available in your setup.

This is a very common scenario in companies and for self-hosting: you are already using these services in your environment and prefer to use the same services for GitLab.

A complete production installation can be performed with Helm. You can refer to the official documentation from GitLab if that is your requirement.

Requirements

You will need the following in order to run GitLab.

Database: Postgres
Cache: Redis
Storage: MinIO is used as object storage for the container registry, GitLab backups, the Terraform storage backend, GitLab artifacts, and more
Ingress Controller: Nginx Ingress
Persistent Volume: Gitaly will store repository data on disk. Your Kubernetes cluster must have a way of provisioning storage. You can install the local path provisioner in your cluster for dynamically provisioning volumes.

Necessary Repositories

Info

You can swap MinIO with any other S3-compatible object storage by changing the connection info secret.

Let's Get Started!

When installing GitLab with Helm, it generates the ConfigMaps after rendering the templates with parameters. We can manually change these values in ConfigMaps, but it's a hassle and not convenient. To make this process easier, we will use a tool called subvars, which will let us render these values from the command line. Install it by following the instructions on the GitHub page. We will use it later.

Download the release with manifests from GitHub. Alternatively, you can clone the repo. If you are cloning the repo, remove the .git folder afterwards, as it sometimes creates issues when rendering multiple versions of the same file with subvars.
```
export RELEASE_VER=1.0
wget -q https://github.com/kha7iq/gitlab-k8s/archive/refs/tags/v${RELEASE_VER}.tar.gz
tar -xf v${RELEASE_VER}.tar.gz
cd gitlab-k8s-${RELEASE_VER}
```

Next, set the URL for our GitLab instance in our Kustomization file. This is located within the ingress-nginx folder. You will find two blocks, one for web-ui and the second for the registry, along with a tls-secret-name for HTTPS.

patch: |-
  - op: replace
    path: /spec/rules/0/host
    value: your-gitlab-url.example.com
  - op: replace
    path: /spec/tls/0/hosts/0
    value: your-gitlab-url.example.com
  - op: replace
    path: /spec/tls/0/secretName
    value: example-com-wildcard-secret

Next, create minio-conn-secret containing the configuration for MinIO. It will be used for all of the enabled S3 buckets except for the GitLab backup, which we will create separately. Create a Kubernetes secret to store this information. The following is an example:

minio.config
cat << EOF > minio.config
provider: AWS
region: us-east-1
aws_access_key_id: 4wsd6c468c0974006d
aws_secret_access_key: 5d5e6c468c0974006cdb41bc4ac2ba0d
aws_signature_version: 4
host: minio.example.com
endpoint: "https://minio.example.com"
path_style: true
EOF

kubectl create secret generic minio-conn-secret \
--from-file=connection=minio.config --dry-run=client -o yaml >minio-connection-secret.yml

Now create a secret with the MinIO configuration, which will be used for the GitLab backup storage. Replace the MinIO endpoint, bucket name, access key, and secret key.

cat << EOF > storage.config
[default]
access_key = be59435b326e8b0eaa
secret_key = 6e0a10bd2253910e1657a21fd1690088
bucket_location = us-east-1
host_base = https://minio.example.com
host_bucket = https://minio.example.com/gitlab-backups
use_https = True
default_mime_type = binary/octet-stream
enable_multipart = True
multipart_max_chunks = 10000
multipart_chunk_size_mb = 128
recursive = True
recv_chunk = 65536
send_chunk = 65536
server_side_encryption = False
signature_v2 = True
socket_timeout = 300
use_mime_magic = False
verbosity = WARNING
website_endpoint = https://minio.example.com
EOF

kubectl create secret generic storage-config --from-file=config=storage.config \
--dry-run=client -o yaml > secrets/storage-config.yml

All other secrets can be used as-is from the repository, or you can change all of them. You may read more about this here.

One of the most important secrets is the gitlab-rails-secret secret. In case of a disaster where you have to restore GitLab from a backup, you must apply the same secret to your cluster, as these keys will be used to decrypt the database from backup. Make sure you keep this consistent after the first install and do not change it.
It's a lot of work to change database details and other parameters one by one in ConfigMaps. I have implemented some templating for this, which can provide all the values of environment variables and render the manifests with subvars. It will output these to a destination folder and replace all the parameters defined as Go templates. The values should be self-explanatory. For example, the GITLAB_GITALY_STORAGE_SIZE variable specifies how much storage is needed for Gitaly, and GITLAB_STORAGE_CLASS is the name of the storage class in your Kubernetes cluster. The following command is an example of how to use this:
```
GITLAB_URL=gitlab.example.com \
GITLAB_REGISTRY_URL=registry.example.com \
GITLAB_PAGES_URL=pages.example.com \
GITLAB_POSTGRES_HOST=192.168.1.90 \
GITLAB_POSTGRES_PORT=5432 \
GITLAB_POSTGRES_USER=gitlab \
GITLAB_POSTGRES_DB_NAME=gitlabhq_production \
GITLAB_REDIS_HOST=192.168.1.91:6379 \
GITLAB_GITALY_STORAGE_SIZE=15Gi \
GITLAB_STORAGE_CLASS=local-path \
subvars dir --input gitlab-k8s-1.0 --out dirName
```
Change into dirName/gitlab-k8s-1.0 so you may review things to confirm everything is in order before applying the changes to the cluster.

The final step is to create the namespace gitlab and build with Kustomize or kubectl. I prefer Kustomize, but you can also use kubectl with the -k flag.

Create the Namespace
kubectl create namespace gitlab

Apply the Final Manifest
kustomize build gitlab-k8s-1.0/ | kubectl apply -f -
# or following if you have already changed into directory
kustomize build . | kubectl apply -f -
# With kubectl
kubectl apply -k  gitlab-k8s-1.0/
# or following if you have already changed into directory
kubectl apply -k  .

Head over to the endpoint you have configured for your GitLab instance, https://gitlab.example.com for example, and log in.

Notes

Default passwords GitLab root user password configured as a secret:

LAwGTzCebner4Kvd23UMGEOFoGAgEHYDszrsSPfAp6lCW15S4fbvrVrubWsua9PI

Postgres password configured as a secret:

ZDVhZDgxNWY2NmMzODAwMTliYjdkYjQxNWEwY2UwZGMK