Connecting a Kubernetes cluster with GitLab

History
  • Introduced in GitLab 13.4.
  • Support for grpcs introduced in GitLab 13.6.
  • Agent server introduced on GitLab.com under wss://kas.gitlab.com through an Early Adopter Program in GitLab 13.10.
  • Introduced in GitLab 13.11, the GitLab agent became available on GitLab.com.
  • Moved from GitLab Premium to GitLab Free in 14.5.
  • GitLab Kubernetes agent renamed to GitLab agent for Kubernetes in GitLab 14.6.
  • Flux recommended as GitOps solution in GitLab 15.10.

You can connect your Kubernetes cluster with GitLab to deploy, manage, and monitor your cloud-native solutions.

To connect a Kubernetes cluster to GitLab, you must first install an agent in your cluster.

The agent runs in the cluster, and you can use it to:

  • Communicate with a cluster, which is behind a firewall or NAT.
  • Access API endpoints in a cluster in real time.
  • Push information about events happening in the cluster.
  • Enable a cache of Kubernetes objects, which are kept up-to-date with very low latency.

For more details about the agent’s purpose and architecture, see the architecture documentation.

Workflows

You can choose from two primary workflows. The GitOps workflow is recommended.

GitOps workflow

You should use Flux for GitOps. To get started, see Tutorial: Set up Flux for GitOps

GitLab CI/CD workflow

In a CI/CD workflow:

  • You configure GitLab CI/CD to use the Kubernetes API to query and update your cluster.

This workflow is considered push-based, because GitLab is pushing requests from GitLab CI/CD to your cluster.

Use this workflow:

  • When you have a heavily pipeline-oriented processes.
  • When you need to migrate to the agent but the GitOps workflow cannot support the use case you need.

This workflow has a weaker security model and is not recommended for production deployments.

Supported Kubernetes versions for GitLab features

GitLab supports the following Kubernetes versions. If you want to run GitLab in a Kubernetes cluster, you might need a different version of Kubernetes:

You can upgrade your Kubernetes version to a supported version at any time:

  • 1.29 (support ends when GitLab version 17.10 is released or when 1.32 becomes supported)
  • 1.28 (support ends when GitLab version 17.5 is released or when 1.31 becomes supported)
  • 1.27 (support ends when GitLab version 17.2 is released or when 1.30 becomes supported)

GitLab aims to support a new minor Kubernetes version three months after its initial release. GitLab supports at least three production-ready Kubernetes minor versions at any given time.

When a new version of Kubernetes is released, we will:

  • Update this page with the results of our early smoke tests within approximately four weeks.
  • If we expect a delay in releasing new version support, we will update this page with the expected GitLab support version within approximately eight weeks.

When installing the agent, use a Helm version compatible with your Kubernetes version. Other versions of Helm might not work. For a list of compatible versions, see the Helm version support policy.

Support for deprecated APIs can be removed from the GitLab codebase when we drop support for the Kubernetes version that only supports the deprecated API.

Some GitLab features might work on versions not listed here. This epic tracks support for Kubernetes versions.

Migrate to the agent from the legacy certificate-based integration

Read about how to migrate to the agent for Kubernetes from the certificate-based integration.

Agent connection

The agent opens a bidirectional channel to KAS for communication. This channel is used for all communication between the agent and KAS:

  • Each agent can maintain up to 500 logical gRPC streams, including active and idle streams.
  • The number of TCP connections used by the gRPC streams is determined by gRPC itself.
  • Each connection has a maximum lifetime of two hours, with a one-hour grace period.
    • A proxy in front of KAS might influence the maximum lifetime of connections. On GitLab.com, this is two hours. The grace period is 50% of the maximum lifetime.

For detailed information about channel routing, see Routing KAS requests in the agent.

Kubernetes integration glossary

This glossary provides definitions for terms related to the GitLab Kubernetes integration.

Term Definition Scope
GitLab agent for Kubernetes The overall offering, including related features and the underlying components agentk and kas. GitLab, Kubernetes, Flux
agentk The cluster-side component that maintains a secure connection to GitLab for Kubernetes management and deployment automation. GitLab
GitLab agent server for Kubernetes (kas) The GitLab-side component of GitLab that handles operations and logic for the Kubernetes agent integration. Manages the connection and communication between GitLab and Kubernetes clusters. GitLab
Pull-based deployment A deployment method where Flux checks for changes in a Git repository and automatically applies these changes to the cluster. GitLab, Kubernetes
Push-based deployment A deployment method where updates are sent from GitLab CI/CD pipelines to the Kubernetes cluster. GitLab
Flux An open-source GitOps tool that integrates with the agent for pull-based deployments. GitOps, Kubernetes
GitOps A set of practices that involve using Git for version control and collaboration in the management and automation of cloud and Kubernetes resources. DevOps, Kubernetes
Kubernetes namespace A logical partition in a Kubernetes cluster that divides cluster resources between multiple users or environments. Kubernetes