ClusterLink Installation Guide¶

The information here is based on ClusterLink documentation.

What is ClusterLink?¶

ClusterLink simplifies the connection between application services that are located in different domains, networks, and cloud infrastructures.

Install clusterlink CLI on a machine¶

For each cluster where clusterlink will run, install clusterlink on the master machine.

Run the installation script:

curl -L https://github.com/clusterlink-net/clusterlink/releases/download/v0.4.0/clusterlink.sh | sh -

Check the installation by running the command:

clusterlink –-version

Create a ClusterLink fabric¶

This is a one-time procedure to build a clusterlink fabric to connect multiple clusters.

Log in to the master machine on your first cluster.

Create a directory named ClusterLink.

From inside the ClusterLink directory, create the fabric’s certificate authority (CA) certificate and private key

clusterlink create fabric

This will create a fabric with the default name: defaut_fabric. This command will create the CA files cert.pem and key.pem in a directory named defaut_fabric. These files will be needed to create clusterlink peers on each cluster where clusterlink is installed.

Connect a cluster to a clusterlink fabric¶

Perform the following procedure on the master node of each cluster added to the fabric (including the first cluster).

Ensure you have a ClusterLink directory with subdirectory default_fabric containing files cert.pem and key.pem.

If necessary, copy these files from the original clusterlink fabric installation.

--/ClusterLink
--/ClusterLink/default_fabric
--/ClusterLink/default_fabric/cert.pem
--/ClusterLink/default_fabric/key.pem

Create a peer certificate¶

Choose <peer_name> to be <ICOS Agent ID>-<ICOS Cluster Name>.

Run the following commands from the ClusterLink directory.

clusterlink create peer-cert --name <peer_name>

Verify that the directory default_fabric/<peer_name> was created with files cert.pem and key.pem in that directory.

--/ClusterLink
--/ClusterLink/default_fabric
--/ClusterLink/default_fabric/cert.pem
--/ClusterLink/default_fabric/key.pem
--/ClusterLink/default_fabric/<peer-name>/cert.pem
--/ClusterLink/default_fabric/<peer-name>/key.pem

Install ClusterLink Deployment¶

clusterlink deploy peer --name <peer_name>

Verify that the ClusterLink control and data plane components are running.

It may take a few seconds for the deployments to be successfully created.

kubectl rollout status deployment cl-controlplane -n clusterlink-system
kubectl rollout status deployment cl-dataplane -n clusterlink-system

Apply an access policy to allow other clusterLink peers to connect.

kubectl apply -f policy.yaml

For policy.yaml, use the following:

apiVersion: clusterlink.net/v1alpha1
kind: AccessPolicy
metadata:
  name: allow-policy
  namespace: default
spec:
  action: allow
  from:
    - workloadSelector: {}
  to:
    - workloadSelector: {}

Set up peers between clusters¶

See example here.

For each peer to which you want to connect, prepare a peer-<peer-name>.yaml file.

It may be easiest to copy some existing peer* files (scp from existing installation, ~/ClusterLink directory) to the ClusterLink directory. Install existing peers on new cluster and install new cluster as a peer on existing clusters that may use resources on the new cluster.

kubectl apply -f peer-xxxx.yaml

The peer-xxxx.yaml file looks like this:

apiVersion: clusterlink.net/v1alpha1
kind: Peer
metadata:
  name: <peer-name>
  namespace: clusterlink-system
spec:
  gateways:
    - host: <peer-address>
      port: 30443

The fields that must be adjusted per instance are the name and host fields.

Export / Import¶

When running an application, define Export and Import of services between peers / clusters. (This should be done by the Deployment Manager.) See example here.

To export a service on a cluster, create a service-export.yaml that looks like this:

apiVersion: clusterlink.net/v1alpha1
kind: Export
metadata:
  name: <service-name>
  namespace: <service-namespace>
spec:
  port: <port-number>

kubectl apply -f service-export.yaml

To import a service on a cluster, create a service-import.yaml that looks like this:

apiVersion: clusterlink.net/v1alpha1
kind: Import
metadata:
  name: <service-name>
  namespace: <service-namespace>
spec:
  port: <port-number>
  sources:
    - exportName:       <service-name>>
      exportNamespace:  <service-namespace>
      peer:             <peer-name>

kubectl apply -f service-import.yaml

To detach cluster from clusterlink fabric¶

clusterlink delete peer –name <peer_name>