goctl Kubernetes

Overview

goctl kube generates production-ready Kubernetes deployment YAML from a single command. Writing K8s manifests by hand is tedious — you need to make many decisions:

How many parameters does a Deployment spec require, and which are easy to get wrong?
How many rollback revisions should be retained?
How should readiness and liveness probes be configured?
How should CPU and memory requests/limits be set?
How do you configure the timezone? (Containers default to UTC, so logs show GMT unless configured otherwise.)
How should the service be exposed to other callers?
How should horizontal pod autoscaling be configured based on CPU and memory usage?

goctl kube handles all of this automatically, producing a ready-to-apply manifest that includes a Deployment, a Service, and two HorizontalPodAutoscaler resources.

goctl Kube directive

$ goctl kube --help
Generate kubernetes files

Usage:
  goctl kube [command]

Available Commands:
  deploy      Generate deployment yaml file

Flags:
  -h, --help   help for kube


Use "goctl kube [command] --help" for more information about a command.

goctl kube currently supports generating deployment YAML files.

goctl kube deploy directive

$ goctl kube deploy --help
Generate deployment yaml file

Usage:
  goctl kube deploy [flags]

Flags:
      --branch string            The branch of the remote repo, it does work with --remote
  -h, --help                     help for deploy
      --home string              The goctl home path of the template, --home and --remote cannot be set at the same time, if they are, --remote has higher priority
      --image string             The docker image of deployment (required)
      --imagePullPolicy string   Image pull policy. One of Always, Never, IfNotPresent
      --limitCpu int             The limit cpu to deploy (default 1000)
      --limitMem int             The limit memory to deploy (default 1024)
      --maxReplicas int          The max replicas to deploy (default 10)
      --minReplicas int          The min replicas to deploy (default 3)
      --name string              The name of deployment (required)
      --namespace string         The namespace of deployment (required)
      --nodePort int             The nodePort of the deployment to expose
      --o string                 The output yaml file (required)
      --port int                 The port of the deployment to listen on pod (required)
      --remote string            The remote git repo of the template, --home and --remote cannot be set at the same time, if they are, --remote has higher priority
                                 The git repo directory must be consistent with the https://github.com/zeromicro/go-zero-template directory structure
      --replicas int             The number of replicas to deploy (default 3)
      --requestCpu int           The request cpu to deploy (default 500)
      --requestMem int           The request memory to deploy (default 512)
      --revisions int            The number of revision history to limit (default 5)
      --secret string            The secret to image pull from registry
      --serviceAccount string    The ServiceAccount for the deployment
      --targetPort int           The targetPort of the deployment, default to port

Parameter field	Parameter Type	Required?	Default value	Parameter Description
branch	string	NO	Empty string	Remote template name is used only if `remote` has value
home	string	NO	`${HOME}/.goctl`	Local Template File Directory
image	string	YES	Empty string	Image name
imagePullPolicy	string	YES	Empty string	Image pull policy, Always: Always pull, Never: Never pull, IfNotPresent: Pull when it does not exist
limitCpu	int	NO	`1000`	cpu resource usage limit
limitMem	int	NO	`1024`	Maximum memory usage
maxReplicas	int	NO	`10`	Maximum number of replicas
minReplicas	int	NO	`3`	Minimum number of replicas
name	string	YES	Empty string	Deployment name
namespace	string	YES	Empty string	Kubernetes namespace
nodePort	int	YES	0	Service port to be exposed
o	string	YES	Empty string	yaml file name
port	int	YES	0	Port to listen
remote	string	NO	Empty string	Remote template is a git repository address. Priority is higher than `home` field value when this field is passed
replicas	int	NO	`3`	Number of replicas
requestCpu	int	NO	`500`	cpu limit
requestMem	int	NO	`512`	Memory limit
revisions	int	NO	`1`	Number of reserved versions, easy to roll back
secret	string	NO	Empty string	Registry image pull secret
serviceAccount	string	NO	Empty string	Service account
targetPort	int	NO	0	Target port

Examples

Using the Redis image as an example, here is how to generate a deployment YAML file with goctl kube deploy.

$ goctl kube deploy -name redis -namespace adhoc -image redis:6-alpine -o redis.yaml -port 6379
Done.

After executing the above command, redis.yaml files will be generated in the current directory, following：

apiVersion: apps/v1
kind: Deployment
metadata:
  name: redis
  namespace: adhoc
  labels:
    app: redis
spec:
  replicas: 3
  revisionHistoryLimit: 5
  selector:
    matchLabels:
      app: redis
  template:
    metadata:
      labels:
        app: redis
    spec:
      containers:
      - name: redis
        image: redis:6-alpine
        ports:
        - containerPort: 6379
        readinessProbe:
          tcpSocket:
            port: 6379
          initialDelaySeconds: 5
          periodSeconds: 10
        livenessProbe:
          tcpSocket:
            port: 6379
          initialDelaySeconds: 15
          periodSeconds: 20
        resources:
          requests:
            cpu: 500m
            memory: 512Mi
          limits:
            cpu: 1000m
            memory: 1024Mi
        volumeMounts:
        - name: timezone
          mountPath: /etc/localtime
      volumes:
        - name: timezone
          hostPath:
            path: /usr/share/zoneinfo/Asia/Shanghai

---

apiVersion: v1
kind: Service
metadata:
  name: redis-svc
  namespace: adhoc
spec:
  ports:
  - port: 6379
    targetPort: 6379
  selector:
    app: redis

---

apiVersion: autoscaling/v2beta1
kind: HorizontalPodAutoscaler
metadata:
  name: redis-hpa-c
  namespace: adhoc
  labels:
    app: redis-hpa-c
spec:
  scaleTargetRef:
    apiVersion: apps/v1
    kind: Deployment
    name: redis
  minReplicas: 3
  maxReplicas: 10
  metrics:
  - type: Resource
    resource:
      name: cpu
      targetAverageUtilization: 80

---

apiVersion: autoscaling/v2beta1
kind: HorizontalPodAutoscaler
metadata:
  name: redis-hpa-m
  namespace: adhoc
  labels:
    app: redis-hpa-m
spec:
  scaleTargetRef:
    apiVersion: apps/v1
    kind: Deployment
    name: redis
  minReplicas: 3
  maxReplicas: 10
  metrics:
  - type: Resource
    resource:
      name: memory
      targetAverageUtilization: 80