How to setup a Nexus instance on a Kubernetes cluster

Requirements

• A kubernetes cluster (that could be minikube, minishift, microk8s, etc.)

• A dedicated namespace for nexus (we are going to use nexus as target namespace)

Steps

1. Create a namespace for nexus

We are going to deploy our nexus instance on a namespace called nexus

kubectl create namespace nexus

2. Create the deployment file.

Let’s create a Deployment.yaml file to describe our nexus deployment.

Here things get a little bit different between nexus 2.x and nexus 3.x. In both cases though we are going to use a volume mount for nexus-data, remember that this is going to be removed when the pod is removed. In production you should probably use some kind of persistent data.

Nexus 2.x

Here we are passing a few customizable ENV variable and adding a volume mount for nexus data.

Deployment.yaml.

    apiVersion: apps/v1
    kind: Deployment
    metadata:
      name: nexus
      namespace: nexus
    spec:
      replicas: 1
      template:
        metadata:
          labels:
            app: nexus-server
        spec:
          containers:
            - name: nexus
              image: sonatype/nexus:latest
              env:
              - name: MAX_HEAP
                value: "800m"
              - name: MIN_HEAP
                value: "300m"
              resources:
                limits:
                  memory: "4Gi"
                  cpu: "1000m"
                requests:
                  memory: "2Gi"
                  cpu: "500m"
              ports:
                - containerPort: 8081
              volumeMounts:
                - name: nexus-data
                  mountPath: /sonatype-work
          volumes:
            - name: nexus-data
              emptyDir: {}

Nexus 3.x

For Nexus 3.x we dont use any custom env variables. You can check the official docker repo for the supported env variables.

Deployment.yaml.

    apiVersion: extensions/v1beta1
    kind: Deployment
    metadata:
      name: nexus
      namespace: nexus
    spec:
      replicas: 1
      selector:
        matchLabels:
            app: nexus-server
      template:
        metadata:
          labels:
            app: nexus-server
        spec:
          containers:
            - name: nexus
              image: sonatype/nexus3:latest
              resources:
                limits:
                  memory: "4Gi"
                  cpu: "1000m"
                requests:
                  memory: "2Gi"
                  cpu: "500m"
              ports:
                - containerPort: 8081
              volumeMounts:
                - name: nexus-data
                  mountPath: /nexus-data
          volumes:
            - name: nexus-data
              emptyDir: {}

3. Create the deployment

Now let’s create the deployment

kubectl create -f Deployment.yaml

You can check the deployment pod status with

kubectl get pod -n nexus

4. Create a service for nexus

Now you need to create a Service.yaml file that will to expose the nexus endpoint using NodePort.

Note

If you are on a cloud, you can expose the service using a load balancer using the service type Loadbalancer. Also, the Prometheus annotations will help in service endpoint monitoring by Prometheus.

Service.yaml.

apiVersion: v1
kind: Service
metadata:
  name: nexus-service
  namespace: devops-tools
  annotations:
      prometheus.io/scrape: 'true'
      prometheus.io/path:   /
      prometheus.io/port:   '8081'
spec:
  selector:
    app: nexus-server
  type: NodePort
  ports:
    - port: 8081
      targetPort: 8081
      nodePort: 32000

Now you can create the service

kubectl create -f Service.yaml

Check the service configuration using kubectl.

kubectl describe service nexus-service -n devops-tools

5. Access nexus

Now you will be able to access nexus on any of the Kubernetes node IP on port 32000/nexus as we have exposed the node port. For example,

Service	Url
Nexus 2	http://35.144.130.153:32000/nexus
Nexus 3	http://35.144.130.153:32000

Note

For Nexus 2.x and Nexus 3 < 3.17 the default username and password will be admin & admin123, while for Nexus 3 >= 3.17 you need to get the password from within the container with cat /nexus-data/admin.password