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Version: v1.1

The Application Model

KubeVela introduces Open Application Model (OAM) to capture a full deployment of micro-services application across hybrid environments.

The Application Deployment Plan

With this model, a typical deployment plan in KubeVela looks as below:

# sample.yaml
apiVersion: core.oam.dev/v1beta1
kind: Application
metadata:
name: website
spec:
components:
- name: frontend # e.g. we want to deploy a frontend component and serves as web service
type: webservice
properties:
image: nginx
traits:
- type: cpuscaler # e.g. we add a CPU based auto scaler to this component
properties:
min: 1
max: 10
cpuPercent: 60
- type: sidecar # add a sidecar container into this component
properties:
name: "sidecar-test"
image: "fluentd"
- name: backend
type: worker
properties:
image: busybox
cmd:
- sleep
- '1000'
policies:
- name: demo-policy
type: env-binding
properties:
envs:
- name: test
placement:
clusterSelector:
name: cluster-test
- name: prod
placement:
clusterSelector:
name: cluster-prod
workflow:
steps:
#workflow step name
- name: deploy-test-env
type: deploy2env
properties:
# Specify the policy name
policy: demo-policy
# Specify the env name in the policy
env: test
- name: manual-approval
# use suspend can stop workflow and wait here until condition changed
type: suspend
- name: deploy-prod-env
type: deploy2env
properties:
# Specify the policy name
policy: demo-policy
# Specify the env name in the policy
env: prod

The building blocks in this entity are explained as below.

Components

An application could be composed by multiple components. KubeVela already built-in with several widely used components definitions to help you model an application deployment, you can list them by using KubeVela CLI:

vela components 

The output shows:

NAME          NAMESPACE   WORKLOAD                              DESCRIPTION
helm vela-system autodetects.core.oam.dev helm release is a group of K8s resources from either git
repository or helm repo
kustomize vela-system autodetects.core.oam.dev kustomize can fetching, building, updating and applying
Kustomize manifests from git repo.
task vela-system jobs.batch Describes jobs that run code or a script to completion.
webservice vela-system deployments.apps Describes long-running, scalable, containerized services
that have a stable network endpoint to receive external
network traffic from customers.
worker vela-system deployments.apps Describes long-running, scalable, containerized services
that running at backend. They do NOT have network endpoint
to receive external network traffic.
alibaba-ack vela-system configurations.terraform.core.oam.dev Terraform configuration for Alibaba Cloud ACK cluster
alibaba-oss vela-system configurations.terraform.core.oam.dev Terraform configuration for Alibaba Cloud OSS object
alibaba-rds vela-system configurations.terraform.core.oam.dev Terraform configuration for Alibaba Cloud RDS object

Traits

Traits are operational behaviors that you can attach to component. KubeVela also has built-in traits installed, search them by using KubeVela CLI:

vela traits 

The result can be:

NAME        NAMESPACE   APPLIES-TO        CONFLICTS-WITH  POD-DISRUPTIVE  DESCRIPTION                                          
annotations vela-system deployments.apps true Add annotations for your Workload.
cpuscaler vela-system webservice,worker false Automatically scale the component based on CPU usage.
ingress vela-system webservice,worker false Enable public web traffic for the component.
labels vela-system deployments.apps true Add labels for your Workload.
scaler vela-system webservice,worker false Manually scale the component.
sidecar vela-system deployments.apps true Inject a sidecar container to the component.

Policy

Policy enforces deployment process of the application, such as quality gates, security groups, placement strategy, fire walls, SLO targets and so on.

Workflow

Workflow allows you to assemble components, operation and task steps into a DAG, and it is process-oriented. Typical workflow steps includes pause, manual verification, waiting state, data flow transmission, multi-environment rollout, and A/B testing, etc.

alt

Each policy and workflow step is a independent capability entity that is fully plugable, KubeVela allows you to create your own step through CUE.

What's Next

Here are some recommended next steps: