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Adding EKS clusters

GitLab supports adding new and existing EKS clusters.

EKS requirements

Before creating your first cluster on Amazon EKS with the GitLab integration, make sure the following requirements are met:

Additional requirements for self-managed instances (CORE ONLY)

If you are using a self-managed GitLab instance, GitLab must first be configured with a set of Amazon credentials. These credentials are used to assume an Amazon IAM role provided by the user creating the cluster. Create an IAM user and ensure it has permissions to assume the role(s) that your users need to create EKS clusters.

For example, the following policy document allows assuming a role whose name starts with gitlab-eks- in account 123456789012:

{
  "Version": "2012-10-17",
  "Statement": {
    "Effect": "Allow",
    "Action": "sts:AssumeRole",
    "Resource": "arn:aws:iam::123456789012:role/gitlab-eks-*"
  }
}

Administration settings

Generate an access key for the IAM user, and configure GitLab with the credentials:

  1. Navigate to Admin Area > Settings > General and expand the Amazon EKS section.

  2. Check Enable Amazon EKS integration.

  3. Enter your Account ID.

  4. Depending on your configuration, enter your access key and ID:

    • GitLab 13.7 and later, and using an instance profile: You may leave Access key ID and Secret access key blank. Read Instance profiles for more information.
    • All GitLab versions: Enter your access key credentials into Access key ID and Secret access key.

  5. Click Save changes.

Instance profiles

Introduced in GitLab 13.7.

You may leave Access key ID and Secret access key fields blank if you are using an instance profile to pass an IAM role to an EC2 instance. Instance profiles dynamically retrieve temporary credentials from AWS when needed.

New EKS cluster

Introduced in GitLab 12.5.

To create and add a new Kubernetes cluster to your project, group, or instance:

  1. Navigate to your:

    • Project's Operations > Kubernetes page, for a project-level cluster.
    • Group's Kubernetes page, for a group-level cluster.
    • Admin Area > Kubernetes, for an instance-level cluster.

  2. Click Add Kubernetes cluster.

  3. Under the Create new cluster tab, click Amazon EKS to display an Account ID and External ID needed for later steps.

  4. In the IAM Management Console, create an IAM policy:

    1. From the left panel, select Policies.

    2. Click Create Policy, which opens a new window.

    3. Select the JSON tab, and paste the following snippet in place of the existing content. These permissions give GitLab the ability to create resources, but not delete them:

      {
    "Version": "2012-10-17",
    "Statement": [
        {
            "Effect": "Allow",
            "Action": [
                "autoscaling:CreateAutoScalingGroup",
                "autoscaling:DescribeAutoScalingGroups",
                "autoscaling:DescribeScalingActivities",
                "autoscaling:UpdateAutoScalingGroup",
                "autoscaling:CreateLaunchConfiguration",
                "autoscaling:DescribeLaunchConfigurations",
                "cloudformation:CreateStack",
                "cloudformation:DescribeStacks",
                "ec2:AuthorizeSecurityGroupEgress",
                "ec2:AuthorizeSecurityGroupIngress",
                "ec2:RevokeSecurityGroupEgress",
                "ec2:RevokeSecurityGroupIngress",
                "ec2:CreateSecurityGroup",
                "ec2:createTags",
                "ec2:DescribeImages",
                "ec2:DescribeKeyPairs",
                "ec2:DescribeRegions",
                "ec2:DescribeSecurityGroups",
                "ec2:DescribeSubnets",
                "ec2:DescribeVpcs",
                "eks:CreateCluster",
                "eks:DescribeCluster",
                "iam:AddRoleToInstanceProfile",
                "iam:AttachRolePolicy",
                "iam:CreateRole",
                "iam:CreateInstanceProfile",
                "iam:CreateServiceLinkedRole",
                "iam:GetRole",
                "iam:listAttachedRolePolicies",
                "iam:ListRoles",
                "iam:PassRole",
                "ssm:GetParameters"
            ],
            "Resource": "*"
        }
    ]
}

      If an error is encountered during the creation process, changes will not be rolled back and you must remove resources manually. You can do this by deleting the relevant CloudFormation stack

    4. Click Review policy.

    5. Enter a suitable name for this policy, and click Create Policy. You can now close this window.

  5. In the IAM Management Console, create an EKS management IAM role. To do so, follow the Amazon EKS cluster IAM role instructions to create a IAM role suitable for managing the AWS EKS cluster's resources on your behalf. In addition to the policies that guide suggests, you must also include the AmazonEKSClusterPolicy policy for this role in order for GitLab to manage the EKS cluster correctly.

  6. In the IAM Management Console, create an IAM role:

    1. From the left panel, select Roles.
    2. Click Create role.
    3. Under Select type of trusted entity, select Another AWS account.
    4. Enter the Account ID from GitLab into the Account ID field.
    5. Check Require external ID.
    6. Enter the External ID from GitLab into the External ID field.
    7. Click Next: Permissions, and select the policy you just created.
    8. Click Next: Tags, and optionally enter any tags you wish to associate with this role.
    9. Click Next: Review.
    10. Enter a role name and optional description into the fields provided.
    11. Click Create role, the new role name displays at the top. Click on its name and copy the Role ARN from the newly created role.

  7. In GitLab, enter the copied role ARN into the Role ARN field.

  8. In the Cluster Region field, enter the region you plan to use for your new cluster. GitLab confirms you have access to this region when authenticating your role.

  9. Click Authenticate with AWS.

  10. Choose your cluster's settings:

    • Kubernetes cluster name - The name you wish to give the cluster.

    • Environment scope - The associated environment to this cluster.

    • Kubernetes version - The Kubernetes version to use.

    • Service role - Select the EKS IAM role you created earlier to allow Amazon EKS and the Kubernetes control plane to manage AWS resources on your behalf.

      NOTE: This IAM role is not the IAM role you created in the previous step. It should be the one you created much earlier by following the Amazon EKS cluster IAM role guide.

    • Key pair name - Select the key pair that you can use to connect to your worker nodes if required.

    • VPC - Select a VPC to use for your EKS Cluster resources.

    • Subnets - Choose the subnets in your VPC where your worker nodes run. You must select at least two.

    • Security group - Choose the security group to apply to the EKS-managed Elastic Network Interfaces that are created in your worker node subnets.

    • Instance type - The instance type of your worker nodes.

    • Node count - The number of worker nodes.

    • GitLab-managed cluster - Leave this checked if you want GitLab to manage namespaces and service accounts for this cluster. See the Managed clusters section for more information.

  11. Finally, click the Create Kubernetes cluster button.

After about 10 minutes, your cluster is ready to go. You can now proceed to install some pre-defined applications.

NOTE: You must add your AWS external ID to the IAM Role in the AWS CLI to manage your cluster using kubectl.

Cluster creation flow

The following sequence illustrates how GitLab works with AWS to create an EKS cluster:

sequenceDiagram
    autonumber
    participant G as GitLab
    participant A as AWS
    participant E as EKS cluster
    alt static credentials
      G->>G: Load AWS Access and secret key
    end
    alt IAM instance profile
      G->>A: Fetch temporary credentials
      A->>G: Temporary access credentials
    end
    G->>A: AssumeRole: EKS Provision Role
    A->>A: Check account, external IDs
    A->>A: Check permissions
    A->>G: New access credentials
    note over G: user selects EKS cluster options
    note over G,A: Use Service Role credentials
    G->>A: CreateStack (CloudFormation)
    A->>G: Received
    G->>G: Wait 5 minutes
    loop Poll for cluster creation
      G->>A: DescribeStacks
      A->>G: CREATE_IN_PROGRESS
    end
    note over G,E: EKS Cluster Created
    G->>A: DescribeStacks
    A->>G: CREATE_COMPLETE
    G->>E: kubectl create role (service account)
    E->>G: OK

First, GitLab must obtain an initial set of credentials to communicate with the AWS API. These credentials can be retrieved in one of two ways:

After GitLab retrieves the AWS credentials, it makes an AssumeRole API call to obtain credentials for the Provision Role. AWS confirms the request has the correct account ID, external ID, and permissions.

If the request is valid, AWS returns a new set of temporary credentials GitLab uses to load the Create cluster options page.

On the Create cluster page, the user must select a Service Role, which is the IAM role that is actually used to create the cluster, and other options such as the Kubernetes cluster name, Kubernetes version, and region. After the user clicks the Create Kubernetes cluster button, GitLab submits a CloudFormation API request to create an EKS cluster with the given parameters from the user. GitLab waits 5 minutes before checking whether the cluster was created, and polls once a minute for up to 30 minutes.

After GitLab receives a CREATE_COMPLETE message from AWS, GitLab talks to the EKS cluster to create a Kubernetes service account with cluster-admin privileges, and updates its internal database to reflect the newly-created Kubernetes cluster. From this point forward, GitLab uses this service account to interact with the cluster.

Troubleshooting creating a new cluster

The following errors are commonly encountered when creating a new cluster.

Validation failed: Role ARN must be a valid Amazon Resource Name

Check that the Provision Role ARN is correct. An example of a valid ARN:

arn:aws:iam::123456789012:role/gitlab-eks-provision'

Access denied: User arn:aws:iam::x is not authorized to perform: sts:AssumeRole on resource: arn:aws:iam::y

This error occurs when the credentials defined in the Administration settings cannot assume the role defined by the Provision Role ARN. Check that:

  1. The initial set of AWS credentials has the AssumeRole policy.

  2. The Provision Role has access to create clusters in the given region.

  3. The account ID and external ID match the value defined in the Trust relationships tab in AWS:

    AWS IAM Trust relationships

Could not load Security Groups for this VPC

When populating options in the configuration form, GitLab returns this error because GitLab has successfully assumed your provided role, but the role has insufficient permissions to retrieve the resources needed for the form. Make sure you've assigned the role the correct permissions.

ROLLBACK_FAILED during cluster creation

The creation process halted because GitLab encountered an error when creating one or more resources. You can inspect the associated CloudFormation stack to find the specific resources that failed to create.

If the Cluster resource failed with the error The provided role doesn't have the Amazon EKS Managed Policies associated with it., the role specified in Role name is not configured correctly.

NOTE: This role should be the role you created by following the EKS cluster IAM role guide. In addition to the policies that guide suggests, you must also include the AmazonEKSClusterPolicy policy for this role in order for GitLab to manage the EKS cluster correctly.

Existing EKS cluster

For information on adding an existing EKS cluster, see Existing Kubernetes cluster.

Create a default Storage Class

Amazon EKS doesn't have a default Storage Class out of the box, which means requests for persistent volumes are not automatically fulfilled. As part of Auto DevOps, the deployed PostgreSQL instance requests persistent storage, and without a default storage class it cannot start.

If a default Storage Class doesn't already exist and is desired, follow Amazon's guide on storage classes to create one.

Alternatively, disable PostgreSQL by setting the project variable POSTGRES_ENABLED to false.

Deploy the app to EKS

With RBAC disabled and services deployed, Auto DevOps can now be leveraged to build, test, and deploy the app.

Enable Auto DevOps if not already enabled. If a wildcard DNS entry was created resolving to the Load Balancer, enter it in the domain field under the Auto DevOps settings. Otherwise, the deployed app isn't externally available outside of the cluster.

Deploy Pipeline

GitLab creates a new pipeline, which begins to build, test, and deploy the app.

After the pipeline has finished, your app runs in EKS, and is available to users. Click on CI/CD > Environments.

Deployed Environment

GitLab displays a list of the environments and their deploy status, as well as options to browse to the app, view monitoring metrics, and even access a shell on the running pod.