sidecartrait

README

SidecarTrait

Deploy sidecar to workload or kubernetes native resources

Supported workloads:

• Pod
• ReplicaSet
• StatefulSet
• Deployment
• ContainerizedWorkload

Prerequisites

Please follow common prerequisites to install OAM Controllers.

Getting started

• Get the SidecarTrait project to your GOPATH

git clone https://github.com/oam-dev/catalog.git

• Install CRD to your Kubernetes cluster

cd catalog/traits/sidecartrait/

make install

• Run the SidecarTrait controller

go run main.go

ContainerizedWorkload

• Apply the sample ContainerizedWorkload

$ kubectl create namespace sidecar-test
$ kubectl -n sidecar-test apply -f config/samples/containerized-workload/difinition
$ kubectl -n sidecar-test apply -f config/samples/containerized-workload/sample_component.yaml
$ kubectl -n sidecar-test apply -f config/samples/containerized-workload/sample_application_config.yaml

# ./config/samples/contaierized/sample_application_config.yaml

  ...
      traits:
        - trait:
            apiVersion: core.oam.dev/v1alpha2
            kind: SidecarTrait
            metadata:
              name: sample-sidecart
            spec:
              container:
                name: nginx-sidecar
                image: nginx:1.13.12
                ports:
                  - containerPort: 8080
                    name: sidecarport
              volumes:
                - name: data
                  emptyDir : {}
                - name: data2
                  emptyDir: {}

• Verify SidecarTrait you should see a deployment created by ContainerizedWorkload

$ kubectl -n sidecar-test  get deployment
NAME                         READY   UP-TO-DATE   AVAILABLE   AGE
example-component   1/1     1            1           15s

$ kubectl -n sidecar-test get deployment -o yaml

  ...
      spec:
        containers:
        - env:
          - name: ALLOW_EMPTY_PASSWORD
            value: "yes"
          image: bitnami/redis:latest
          name: redis-main
          ports:
          - containerPort: 6379
            name: redisport
            protocol: TCP
        - image: nginx:1.13.12
          name: nginx-sidecar
          ports:
          - containerPort: 8080
            name: sidecarport
            protocol: TCP

        volumes:
        - emptyDir: {}
          name: data
        - emptyDir: {}
          name: data2
  ...

How it work?

Essentially, the SidecarTrait controller will patch the corresponding resources based on the workload spec.

In detail:

• If the workload type is ContainerizedWorkload which has two child resources (Deployment and Service), SidecarTrait can deploy sidecar to Deployment
• If the workload type is K8S native resources (StatefulSet, Deployment, Pod, ReplicaSet), SidecarTrait can deploy sidecar based on spec.template.spec.containers or spec.containers.