Catégorie : Devops

Deploy Snipe It with Kubernetes

In the previous post, we spoke about Snipe It and how to deploy it with docker. As is a simple product let’s introduce how to deploy this simple tool with Kubernetes.

First let’s introduce Kubernetes.

Kubernetes is an open-source platform for managing containerized workloads and services. Kubernetes manage containers system resiliently. It takes care of scaling and failover for your application, provides deployment patterns, and more.

Kubernetes works with several components:

Kubernetes is deployed with a Cluster who consists of a set of worker machines, called nodes, that run containerized applications. Every cluster has at least one worker node.

The worker node(s) host the Pods that are the components of the application workload. The control plane manages the worker nodes and the Pods in the cluster. In production environments, the control plane usually runs across multiple computers and a cluster usually runs multiple nodes, providing fault-tolerance and high availability.

You will find all the informations needed to https://kubernetes.io/docs/concepts/overview/what-is-kubernetes/

apiVersion: apps/v1
kind: Deployment

metadata:
  name: snipedb
  labels:
    app: snipe
spec:
  selector:
    matchLabels:
      app: snipe
      tier: snipedb
  strategy:
    type: Recreate
  template:
    metadata:
      labels:
        app: snipe
        tier: snipedb
    spec:
      containers:
        - name: snipedb 
          image: mariadb
          resources:
            limits:
              memory: 512Mi
              cpu: "1"
            requests:
              memory: 256Mi
              cpu: "0.2"
          ports:
            - containerPort: 3306 
          volumeMounts:
            - name: snipedb-pvolume
              mountPath: /var/lib/snipeit
          env: 
            - name: MYSQL_ROOT_PASSWORD
              value: "mysql_root_password"
            - name: MYSQL_DATABASE
              value: "snipe"
            - name: MYSQL_USER
              value: "snipeit"
            - name: MYSQL_PASSWORD
              value: "mysql_password"
      volumes:
        - name: snipedb-pvolume
          persistentVolumeClaim:
            claimName: snipedb-pvolume
---
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: snipedb-pvolume
  labels:
    app: snipedb
spec:
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 5Gi

The Deployment Metadata name is snipedb and it’s tagged with the labels app snipe. Labels are key/value pairs that are attached to objects, such as pods. Labels can be used to organize and to select subsets of objects.

The .spec.strategy.type==Recreate will kill all the previous pods before create new.

in .template.spec we will retrieve all the configs for the pods, we create the volume snipedb-pvolume who use the PersistantVolumeClaim snipedb-pvolume. A volume snipedb-pvolume has been created in .template.spec.containers.volumeMounts this volume use the declarated volume in .template.spec.volumes

The persistentVolumClaim .spec.accessModes has been setup in ReadWriteOnce. That means the volume can be mounted as read-write by a single node. Multiple pods under same nodes can access to Volume.

As the mysql we will create a deployment and a PersistantVolumeClaim for the snipe app.

Now let’s check the snipe_deployments.yml file

apiVersion: apps/v1
kind: Deployment
metadata:
  name: snipe
spec:
  selector:
    matchLabels:
      app: snipe 
      tier: frontend
  strategy:
    type: Recreate
  template:
    metadata:
      labels:
        app: snipe
        tier: frontend
    spec:
      containers:
        - name: snipe
          image: snipe/snipe-it:latest
          livenessProbe:
            httpGet:
              port: 80
          resources:
            limits:
              memory: 512Mi
              cpu: "1"
            requests:
              memory: 256Mi
              cpu: "0.2"
          ports:
            - containerPort: 80
          volumeMounts:
            - name: snipe-pvolume
              mountPath: /var/lib/snipeit     
          env:
            - name: APP_ENV
              value: "preproduction"
            - name: APP_DEBUG
              value: "true"
            - name: APP_KEY
              value: "base64:D5oGA+zhFSVA3VwuoZoQ21RAcwBtJv/RGiqOcZ7BUvI="
            - name: APP_URL
              value: "http://127.0.0.1:9000"
            - name: APP_TIMEZONE
              value: "Europe/Paris"
            - name: APP_LOCALE
              value: "en"
            - name: DB_CONNECTION
              value: "mysql"
            - name: DB_HOST
              value: "snipedb"
            - name: DB_DATABASE
              value: "snipe"
            - name: DB_USERNAME
              value: "snipeit"
            - name: DB_PASSWORD
              value: ""
            - name: DB_PORT
              value: "3306"
            - name: MAIL_PORT_587_TCP_ADDR
              value: "smtp.gmail.com"
            - name: MAIL_PORT_587_TCP_PORT
              value: "587"
            - name: MAIL_ENV_FROM_ADDR
              value: "mail@domain.com"
            - name: MAIL_ENV_FROM_NAME
              value: ""
            - name: MAIL_ENV_ENCRYPTION
              value: "tls"
            - name: MAIL_ENV_USERNAME
              value: "mail@domain.com" 
            - name: MAIL_ENV_PASSWORD
              value: ""         
      volumes:
        - name: snipe-pvolume
          persistentVolumeClaim:
            claimName: snipe-pvolume
---
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: snipe-pvolume
  labels:
    app: snipe
spec:
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 5Gi

The container image snipe/snipe-it:latest it’s used.

.spec.container.livenessprobe it’s used to know when to restart a container.

With snipe_deployments.yml and mariadb_deployment.yml we have the Deployments ready.

We have now to deploy Services to expose an application running on a set of Pods as a network service.

The snipe_services.yml will be used to expose Snipe app port 80 and databse 3306 port.

apiVersion: v1
kind: Service
metadata:
  name: snipe-entrypoint
  labels:
    app: snipe
spec:
  ports:
    - port: 80
  selector:
    app: snipe
    tier: frontend
  clusterIP: None

---
apiVersion: v1
kind: Service
metadata:
  name: snipedb
  labels:
    app: snipedb
spec:
  ports:
    - port: 3306
  selector:
    app: snipe
    tier: snipedb
  clusterIP: None

Now we should have a folder with three files snipe_deployments.yml, mariadb_deployments.yml and snipe_services.yml.

To generate the application run from command line the command

kubectl apply -f ./

this command will apply all the files and generate all the components.

Finally add a forward port to the service with the command

kubectl port-forward service/snipe-entrypoint 9000:80

Use command kubectl-get, kubectl describe for have more information on the running apps.

https://kubernetes.io/docs/reference/generated/kubectl/kubectl-commands