kratos

README

Kratos

Yep another deployment tools

Kratos is simple, but with simplicity come less flexibility, so if you want a full fledge deploying tools, this is propably not for you. But, if you have some simple container, maybe a nginx with your html5 website, this may be the perfect alternative to custom Kubernetes YAML, or the build of helm templates.

Use case

I had a little html5 demo container that I wanted to host on my Kubernetes cluster. To deploy on my cluster I have 2 options at hand (ok, I haven't search for others options beside these two):

• Helm template packaging
• Kubernetes yaml files

These solutions are not difficult (if you are familiar with Kubernetes), but time consuming (and yes boring).

So Kratos is born from this use case.

Status

Under heavy developpment, use at your own risk.

Contribution are welcome.

Prerequisite

• Kubernetes 1.19+
• Golang 1.18+ for building
• Certmanager for TLS certificates
• A working kubeconfig configuration

Cmdline

Alternative to helm for deploying simple container, without the pain of managing Kubernetes yaml templates.

Usage:
  kratos [command]

Available Commands:
  create      Deploy an application.
  delete      Delete an application.
  get         Retreive a configuration of deployed application.
  help        Help about any command.
  init        Create an empty configuration file.
  list        List applications.
  update      Update an application.
  version     Show version of kratos.

Flags:
  -h, --help                help for kratos
  -k, --kubeconfig string   kubernetes configuration file (default "/home/user/.kube/config")

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

Security restriction

Kratos don't support deployment of container running as root. If you deploy a container running as root, it will fail to start, with this error:

Error: container has runAsNonRoot and image will run as root (pod: "pacman-7dc78bcb9c-hwjhp_static(11b8ab59-0a7f-45ca-87fd-3c3348e9fc7f)", container: pacman)

Kratos don't mount the Kubernetes service account token in the containers. These token are useful only to application who need access to Kubernetes API.

podSpec configurations:

• RunAsNonRoot is true

• AutomountServiceAccountToken is false

Initialize a configuration file

You need to create a configuration file, you can build it from scratch, or use the init command:

kratos init --name myappconfig.yaml

You can now just fill the configuration with your own config values. It's very similar to helm values.yaml file.

Deploy your application

With your configuration ready, you can now deploy to Kubernetes:

kratos create --name myapp --namespace mynamespace --config myappconfig.yaml

Config

Values definition

Values	Descriptions	Mandatory
common.labels	Labels common to all Kubernetes objects	no
common.annotations	Annotation common to all Kubernetes objects	no
deployment.labels	Deployment & pod labels	no
deployment.annotations	Deployment & pod annotations	no
deployment.replicas	Numbers of pod replicas	yes
deployment.port	Port to use for communication with pod	yes
deployment.containers	List of containers in the pods	yes
deployment.containers.name	Name of the containers	yes
deployment.containers.image	Name of the Docker image	yes
deployment.containers.tag	Tag version of the image	yes
deployment.containers.resources.requests.cpu	Request this amount of CPU	no
deployment.containers.resources.requests.memory	Request this amount of RAM	no
deployment.containers.resources.limits.cpu	Max amount of CPU	no
deployment.containers.resources.limites.memory	Max amount of RAM	no
deployment.containers.health	Healthcheck configuration for the container	no
deployment.containers.health.live	Liveness check	no
deployment.containers.health.live.probe	URI to use for the check	yes
deployment.containers.health.live.port	Port of the container	yes
deployment.containers.health.live.initialDelaySeconds	Delay the check for x seconds at startup	no
deployment.containers.health.live.periodSeconds	Time between check in second	no
deployment.containers.health.ready	Readyness check	no
deployment.containers.health.ready.probe	URI to use for the check	yes
deployment.containers.health.ready.port	Port of the container	yes
deployment.containers.health.ready.initialDelaySeconds	Delay the check for x seconds at startup	no
deployment.containers.health.ready.periodSeconds	Time between check in second	no
deployment.ingress.labels	Ingress labels	no
deployment.ingress.annotations	Ingress annotations	no
deployment.ingress.ingressClass	Name of the ingressClass to use	yes
deployment.ingress.clusterIssuer	Name of the clusterIssuer to use	yes
deployment.ingress.hostnames	List of hostnames associate with this deployment	yes
cronjobs.labels	Cronjobs labels	no
cronjobs.annotations	Cronjobs annotation	no
cronjobs.schedule	Cronjobs schedule definition	yes
cronjobs.retry	Number of retry if jobs fail	no
cronjobs.container	container definition	yes
cronjobs.container.name	Name of the containers	yes
cronjobs.container.image	Name of the Docker image	yes
cronjobs.container.tag	Tag version of the image	yes
cronjobs.container.resources.requests.cpu	Request this amount of CPU	no
cronjobs.container.resources.requests.memory	Request this amount of RAM	no
cronjobs.container.resources.limits.cpu	Max amount of CPU	no
cronjobs.container.resources.limites.memory	Max amount of RAM	no
configmaps	List of configmaps	no
configmaps.labels	Configmaps labels	no
configmaps.annotations	Configmaps annotations	no
configmaps.files	List of configmaps files	yes
configmaps.files.name	Name of the configmaps	yes
configmaps.files.mount	How to use the configmaps	yes
configmaps.files.mount.path	Path of the mount point in the pod	yes
configmaps.files.mount.exposedTo	List of containers to expose the configmap	no
configmaps.data	Contents of the configmap	yes
secrets	List of secrets	no
secrets.labels	Secrets labels	no
secrets.annotation	Secrets annotations	no
secrets.files	List of secrets files	yes
secrets.files.name	Name of the secret	yes
secrets.files.mount	How to use the secret	yes
secrets.files.mount.path	Path of the mount point in the pod	yes
secrets.files.mount.exposedTo	List of containers to expose the secret	no
secrets.files.data	Contents of the secret	yes

Example of a full features configuration

common:
  labels: {}
  annotations: {}

deployment:
  labels: {}
  annotations: {}
  replicas: 1
  port: 80
  containers:
    - name: pacman
      image: laghoule/patate-poil
      tag: v1.0.1
      resources:
        requests:
          cpu: 25m
          memory: 32Mi
        limits:
          cpu: 50m
          memory: 64Mi
      health:
        live:
          probe: /isLive
          initialDelaySeconds: 3
          periodSeconds: 3
        ready:
          probe: /isReady
          initialDelaySeconds: 3
          periodSeconds: 3
  ingress:
    labels: {}
    annotations: {}
    ingressClass: nginx
    clusterIssuer: letsencrypt
    hostnames:
      - example.com
      - www.example.com

cronjob:
  labels: {}
  annotations: {}
  schedule: 0 0 * * *
  retry: 1
  container:
    name: myjobs
    image: laghoule/crunchdata
    tag: v1.0.0
    resources:
      requests:
        cpu: 25m
        memory: 32Mi
      limits:
        cpu: 50m
        memory: 64Mi

configmaps:
  labels: {}
  annotations: {}
  files:
    - name: configuration.yaml
      mount:
        path: /etc/cfg
        exposedTo:
          - pacman
          - myjobs
      data: |
        my configuration data

secrets:
  labels: {}
  annotations: {}
  files:
    - name: credentials.yaml
      mount:
        path: /etc/cfg
        exposedTo:
          - myjobs
      data: |
        usename: patate
        password: poil

Example of a minimal configuration

Deployment

deployment:
  replicas: 1
  port: 80
  containers:
    - name: pacman
      image: laghoule/patate-poil
      tag: v1.0.1
  ingress:
    ingressClass: nginx
    clusterIssuer: letsencrypt
    hostnames:
      - example.com
      - www.example.com

Cronjobs

cronjob:
  schedule: 0 0 * * *
  container:
    name: myjobs
    image: laghoule/crunchdata
    tag: v1.0.0