Rollout

This chapter will introduce how to use Rollout Trait to perform a rolling update on Workload.

How to

First Deployment

Apply the Application YAML below which includes a webservice-type workload with Rollout Trait, and control version of component name to be express-server-v1.

cat <<EOF | kubectl apply -f -
apiVersion: core.oam.dev/v1beta1
kind: Application
metadata:
  name: rollout-trait-test
spec:
  components:
    - name: express-server
      type: webservice
      externalRevision: express-server-v1
      properties:
        image: stefanprodan/podinfo:4.0.3
      traits:
        - type: rollout
          properties:
            targetSize: 5
            rolloutBatches:
              - replicas: 2
              - replicas: 3
EOF

This Rollout Trait has target size of 5 and two rollout batches. The first batch has 2 replicas and second batch has 3. Only after all replicas in the first batch are ready, it will start to rollout the second batch.

Check the Application status whether the rollout is successful:

$ kubectl get app rollout-trait-test
NAME                 COMPONENT        TYPE         PHASE     HEALTHY   STATUS   AGE
rollout-trait-test   express-server   webservice   running   true               2d20h

Check component revision

$ kubectl get controllerRevision  -l controller.oam.dev/component=express-server
NAME                CONTROLLER                                    REVISION   AGE
express-server-v1   application.core.oam.dev/rollout-trait-test   1          2d22h

Check the status of Rollout Trait. The rollout is successful only if ROLLING-STATE equals rolloutSucceed, and all replicas are ready only if BATCH-STATE equals batchReady. TARGET, UPGRADED and READY indicates target size of replicas is 5, updated number of replicas is 5 and all 5 replicas are ready.

$ kubectl get rollout express-server
NAME             TARGET   UPGRADED   READY   BATCH-STATE   ROLLING-STATE    AGE
express-server   5        5          5       batchReady    rolloutSucceed   2d20h

Check Workload Status (Underlying resource behind the workload is deployment)

$ kubectl get deploy -l app.oam.dev/component=express-server
NAME                READY   UP-TO-DATE   AVAILABLE   AGE
express-server-v1   5/5     5            5           2d20h

Rollout Update

Apply the YAML below to modify the image of the container. It will generate a new ControllerRevision.

cat <<EOF | kubectl apply -f -
apiVersion: core.oam.dev/v1beta1
kind: Application
metadata:
  name: rollout-trait-test
spec:
  components:
    - name: express-server
      type: webservice
      externalRevision: express-server-v2
      properties:
        image: stefanprodan/podinfo:5.0.2
      traits:
        - type: rollout
          properties:
            targetSize: 5
            batchPartition: 0
            rolloutBatches:
              - replicas: 2
              - replicas: 3
EOF

This Rollout Trait represents the target size of replicas is 5 and update will be performed in 2 batches. The first batch will update 2 replicas and the second batch will update 3 replicas. Only 2 replicas in first batch will be updated by setting batchPartition to 0.

Check controllerRevision and there is a new controllerRevision express-server-v2.

$ kubectl get controllerRevision -l controller.oam.dev/component=express-server
NAME                CONTROLLER                                    REVISION   AGE
express-server-v1   application.core.oam.dev/rollout-trait-test   1          2d22h
express-server-v2   application.core.oam.dev/rollout-trait-test   2          1m

Check the status of Rollout Trait after a while when first batch has been upgraded successfully. TARGET, UPGREADED and READY indicates the target size of replicas for this revision is 5, there are 2 replicas sucessfully upgraded and they are ready. batchReady means replicas in the first rolloutBatch are all ready, rollingInBatches means there are batches still yet to be upgraded.

$ kubectl get rollout express-server
NAME             TARGET   UPGRADED   READY   BATCH-STATE   ROLLING-STATE    AGE
express-server   5        2          2       batchReady   rollingInBatches  2d20h

Check Workload status to verify, we can see there are 2 replicas of new Workload express-server-v2 have been upgraded and old version of Workload express-server-v1 still has 3 replicas.

$ kubectl get deploy -l app.oam.dev/component=express-server
NAME                READY   UP-TO-DATE   AVAILABLE   AGE
express-server-v1   3/3     3            3           2d20h
express-server-v2   2/2     2            2           1m

Apply the YAML below without batchPartition field in Rollout Trait to upgrade all replicas to latest revision.

cat <<EOF | kubectl apply -f -
apiVersion: core.oam.dev/v1beta1
kind: Application
metadata:
  name: rollout-trait-test
spec:
  components:
    - name: express-server
      type: webservice
      externalRevision: express-server-v2
      properties:
        image: stefanprodan/podinfo:5.0.2
      traits:
        - type: rollout
          properties:
            targetSize: 5
            rolloutBatches:
              - replicas: 2
              - replicas: 3
EOF

Check Rollout Trait, we can see rollout is succeed.

$ kubectl get rollout express-server
NAME             TARGET   UPGRADED   READY   BATCH-STATE   ROLLING-STATE    AGE
express-server   5        5           5       batchReady   rolloutSucceed  2d20h

Check Workload status, all replicas of Workload has been upgraded to a new revision and old workload has been deleted.

$ kubectl get deploy -l app.oam.dev/component=express-server
NAME                READY   UP-TO-DATE   AVAILABLE   AGE
express-server-v2   5/5     5            5           1m

Rollback

Apply the YAML below to make controllerRevision roll back to express-server-v1 by assigning targetRevision field to express-server-v1 in Rollout Trait.

cat <<EOF | kubectl apply -f -
apiVersion: core.oam.dev/v1beta1
kind: Application
metadata:
  name: rollout-trait-test
spec:
  components:
    - name: express-server
      type: webservice
      externalRevision: express-server-v2
      properties:
        image: stefanprodan/podinfo:5.0.2
      traits:
        - type: rollout
          properties:
            targetRevision: express-server-v1
            targetSize: 5
            rolloutBatches:
              - replicas: 2
              - replicas: 3
EOF

Check Rollout Trait status after rollback has been succeed.

$ kubectl get rollout express-server
NAME             TARGET   UPGRADED   READY   BATCH-STATE   ROLLING-STATE    AGE
express-server   5        5          5       batchReady    rolloutSucceed  2d20h

Check Workload status, we can see Workload has rolled back to express-server-v1.

$ kubectl get deploy -l app.oam.dev/component=express-server
NAME                READY   UP-TO-DATE   AVAILABLE   AGE
express-server-v1   5/5     5            5           15s

Scale up

Rollout Trait also be able to scale up a Workload, apply the YAML below to modify the targetSize, in order to increase the number of replicas from 5 to 7.

cat <<EOF | kubectl apply -f -
apiVersion: core.oam.dev/v1beta1
kind: Application
metadata:
  name: rollout-trait-test
spec:
  components:
    - name: express-server
      type: webservice
      externalRevision: express-server-v2
      properties:
        image: stefanprodan/podinfo:5.0.2
      traits:
        - type: rollout
          properties:
            targetRevision: express-server-v1
            targetSize: 7
            rolloutBatches:
              - replicas: 1
              - replicas: 1
EOF

This Rollout Trait represents this expansion consists of 2 rollout batches, each batch will scale 1 replica.

Check the status after expansion has been succeed.

$ kubectl get rollout express-server
NAME             TARGET   UPGRADED   READY   BATCH-STATE   ROLLING-STATE    AGE
express-server   7        7          7       batchReady    rolloutSucceed   2d20h

$ kubectl get deploy -l app.oam.dev/component=express-server
NAME                READY   UP-TO-DATE   AVAILABLE   AGE
express-server-v1   7/7     7            7           2m

Scale down

Apply the YAML below to scale down the size of replicas from 7 to 3.

cat <<EOF | kubectl apply -f -
apiVersion: core.oam.dev/v1beta1
kind: Application
metadata:
  name: rollout-trait-test
spec:
  components:
    - name: express-server
      type: webservice
      externalRevision: express-server-v2
      properties:
        image: stefanprodan/podinfo:5.0.2
      traits:
        - type: rollout
          properties:
            targetRevision: express-server-v1
            targetSize: 3
            rolloutBatches:
              - replicas: 1
              - replicas: 3
EOF

This Rollout Trait represents this scale down consists of 2 batches, first batch will remove 1 replica and second batch will remove 3 replicas.

Check the status after scale up has been succeed.

$ kubectl get rollout express-server
NAME             TARGET   UPGRADED   READY   BATCH-STATE   ROLLING-STATE    AGE
express-server   3        3          3       batchReady    rolloutSucceed   2d20h

$ kubectl get deploy -l app.oam.dev/component=express-server
NAME                READY   UP-TO-DATE   AVAILABLE   AGE
express-server-v1   3/3     3            3           5m

Rollout cloneset type Workload

You need to enable kruise addon。

$ vela addon enable kruise

Check types of components.

$ vela components
NAME                NAMESPACE        WORKLOAD                        DESCRIPTION
cloneset           vela-system     clonesets.apps.kruise.io

Apply the YAML below to create an Application, this Application includes a Workload of type cloneset with a Rollout Trait.

cat <<EOF | kubectl apply -f -
apiVersion: core.oam.dev/v1beta1
kind: Application
metadata:
  name: rollout-trait-test-cloneset
spec:
  components:
    - name: cloneset-server
      type: cloneset
      externalRevision: cloneset-server-v1
      properties:
        image: stefanprodan/podinfo:4.0.3
      traits:
        - type: rollout
          properties:
            targetSize: 5
            rolloutBatches:
              - replicas: 2
              - replicas: 3
EOF

Check the status of related resources.

$ kubectl get app rollout-trait-test-cloneset
NAME                              COMPONENT         TYPE               PHASE      HEALTHY   STATUS     AGE
rollout-trait-test-cloneset        cloneset   clonesetservice          running      true               4m18s

$ kubectl get controllerRevision  -l controller.oam.dev/component=cloneset-server
NAME                CONTROLLER                                           REVISION   AGE
cloneset-server-v1   application.core.oam.dev/rollout-trait-test-cloneset   1          4m45s

$ kubectl get rollout cloneset-server
NAME             TARGET   UPGRADED   READY   BATCH-STATE   ROLLING-STATE    AGE
cloneset-server   5        5          5       batchReady    rolloutSucceed   5m10s

Check the status of Workload. As cloneset Workload supports in-place upgrade, the most noticeable difference between it and webservice/worker is that the name of underlying Workload's name is exactly the component's name.

$ kubectl get cloneset -l app.oam.dev/component=cloneset-server
NAME             DESIRED   UPDATED   UPDATED_READY   READY   TOTAL   AGE
cloneset-server   5         5         5               5       5       7m3s

Check the image.

$ kubectl get cloneset cloneset-server -o=jsonpath='{.spec.template.spec.containers[0].image}'
stefanprodan/podinfo:4.0.3

Apply the YAML below to upgrade the image.

cat <<EOF | kubectl apply -f -
apiVersion: core.oam.dev/v1beta1
kind: Application
metadata:
  name: rollout-trait-test-cloneset
spec:
  components:
    - name: cloneset-server
      type: cloneset
      externalRevision: cloneset-server-v2
      properties:
        image: stefanprodan/podinfo:5.0.2
      traits:
        - type: rollout
          properties:
            targetSize: 5
            rolloutBatches:
              - replicas: 2
              - replicas: 3
EOF

Check the status of related resources after upgrade has been succeed.

$ kubectl get controllerRevision  -l controller.oam.dev/component=cloneset-server
NAME                CONTROLLER                                             REVISION    AGE
cloneset-server-v1   application.core.oam.dev/rollout-trait-test-cloneset    1          6m43s
cloneset-server-v2   application.core.oam.dev/rollout-trait-test-clonesett   2          108s

$ kubectl get rollout cloneset-server
NAME             TARGET   UPGRADED   READY   BATCH-STATE   ROLLING-STATE    AGE
cloneset-server  5        5          5       batchReady    rolloutSucceed   6m10s

Check the status of the Workload, we can see the name after upgrade is still cloneset-server.

$ kubectl get cloneset -l app.oam.dev/component=cloneset-server
NAME             DESIRED   UPDATED   UPDATED_READY   READY   TOTAL   AGE
cloneset-server   5         5         5               5       5       7m3s

Verify the rollout by checking the image.

$ kubectl get cloneset cloneset-server -o=jsonpath='{.spec.template.spec.containers[0].image}'
stefanprodan/podinfo:5.0.2

Other operations such as Scale up, Scale down, Rollback are the same as the operations on webservice/worker.

Configurations

All configurations for Rolling Traits.

Name	Description	Type	Required	Default
targetRevision	The target ComponentRevision	string	No	If this field is empty, it will always point to the latest revision
targetSize	Number of target Workload's replicas	int	Yes	Nil
rolloutBatches	Strategy of rolling update	[]rolloutBatch	Yes	Nil
batchPartition	Partition of rolloutBatches	int	No	Nil, if this field is empty, all batches will be updated

Configurations of rolloutBatch

Name	Description	Type	Required	Default
replicas	number of replicas in one batch	int	Yes	Nil

Supported workload type

Rollout Trait supports following workload types: webservice,worker and cloneset.

When using webservice/worker as Workload type with Rollout Trait, Workload's name will be controllerRevision's name. And when Workload's type is cloneset, because of clonset support in-place update Workload's name will always be component's name.