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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.

NameDescriptionTypeRequiredDefault
targetRevisionThe target ComponentRevisionstringNoIf this field is empty, it will always point to the latest revision
targetSizeNumber of target Workload's replicasintYesNil
rolloutBatchesStrategy of rolling update[]rolloutBatchYesNil
batchPartitionPartition of rolloutBatchesintNoNil, if this field is empty, all batches will be updated

Configurations of rolloutBatch

NameDescriptionTypeRequiredDefault
replicasnumber of replicas in one batchintYesNil

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.

Last updated on by Jianbo Sun