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Chapter 3. Getting started with Argo Rollouts
Argo Rollouts supports canary and blue-green deployment strategies. This guide provides instructions with examples using a canary deployment strategy to help you deploy, update, promote and manually abort rollouts.
With a canary-based deployment strategy, you split traffic between two application versions:
- Canary version: A new version of an application where you gradually route the traffic.
- Stable version: The current version of an application. After the canary version is stable and has all the user traffic directed to it, it becomes the new stable version. The previous stable version is discarded.
3.1. Prerequisites
- You have logged in to the OpenShift Container Platform cluster as an administrator.
- You have access to the OpenShift Container Platform web console.
- You have installed Red Hat OpenShift GitOps on your OpenShift Container Platform cluster.
- You have installed Argo Rollouts on your OpenShift Container Platform cluster.
- You have installed the Argo Rollouts CLI on your system.
3.2. Deploying a rollout
As a cluster administrator, you can configure Argo Rollouts to progressively route a subset of user traffic to a new application version. Then you can test whether the application is deployed and working.
The following example procedure creates a rollouts-demo
rollout and service. The rollout then routes 20% of traffic to a canary version of the application, waits for a manual promotion, and then performs multiple automated promotions until it routes the entire traffic to the new application version.
Procedure
-
In the Administrator perspective of the web console, click Operators
Installed Operators Red Hat OpenShift GitOps Rollout. -
Create or select the project in which you want to create and configure a
Rollout
custom resource (CR) from the Project drop-down menu. Click Create Rollout and enter the following configuration in the YAML view:
apiVersion: argoproj.io/v1alpha1 kind: Rollout metadata: name: rollouts-demo spec: replicas: 5 strategy: canary: 1 steps: 2 - setWeight: 20 3 - pause: {} 4 - setWeight: 40 - pause: {duration: 45} 5 - setWeight: 60 - pause: {duration: 20} - setWeight: 80 - pause: {duration: 10} revisionHistoryLimit: 2 selector: matchLabels: app: rollouts-demo template: 6 metadata: labels: app: rollouts-demo spec: containers: - name: rollouts-demo image: argoproj/rollouts-demo:blue ports: - name: http containerPort: 8080 protocol: TCP resources: requests: memory: 32Mi cpu: 5m
- 1
- The deployment strategy that the rollout must use.
- 2
- Specify the steps for the rollout. This example gradually routes 20%, 40%, 60%, and 80% of traffic to the canary version.
- 3
- The percentage of traffic that must be directed to the canary version. A value of 20 means that 20% of traffic is directed to the canary version.
- 4
- Specify to the Argo Rollouts controller to pause indefinitely until it finds a request for promotion.
- 5
- Specify to the Argo Rollouts controller to pause for a duration of 45 seconds. You can set the duration value in seconds (
s
), minutes (m
), or hours (h
). For example, you can specify1h
for an hour. If no value is specified, the duration value defaults to seconds. - 6
- Specifies the pods that are to be created.
Click Create.
NoteTo ensure that the rollout becomes available quickly on creation, the Argo Rollouts controller automatically treats the
argoproj/rollouts-demo:blue
initial container image specified in the.spec.template.spec.containers.image
field as a stable version. In the initial instance, the creation of theRollout
resource routes all of the traffic towards the stable version of the application and skips the part where the traffic is sent to the canary version. However, for all subsequent application upgrades with the modifications to the.spec.template.spec.containers.image
field, the Argo Rollouts controller performs the canary steps, as usual.Verify that your rollout was created correctly by running the following command:
$ oc argo rollouts list rollouts -n <namespace> 1
- 1
- Specify the namespace where the
Rollout
resource is defined.
Example output
NAME STRATEGY STATUS STEP SET-WEIGHT READY DESIRED UP-TO-DATE AVAILABLE rollouts-demo Canary Healthy 8/8 100 5/5 5 5 5
Create the Kubernetes services that targets the
rollouts-demo
rollout.-
In the Administrator perspective of the web console, click Networking
Services. Click Create Service and enter the following configuration in the YAML view:
apiVersion: v1 kind: Service metadata: name: rollouts-demo spec: ports: 1 - port: 80 targetPort: http protocol: TCP name: http selector: 2 app: rollouts-demo
Click Create.
Rollouts automatically update the created service with pod template hash of the canary
ReplicaSet
. For example,rollouts-pod-template-hash: 687d76d795
.
-
In the Administrator perspective of the web console, click Networking
Watch the progression of your rollout by running the following command:
$ oc argo rollouts get rollout rollouts-demo --watch -n <namespace> 1
- 1
- Specify the namespace where the
Rollout
resource is defined.
Example output
Name: rollouts-demo Namespace: spring-petclinic Status: ✔ Healthy Strategy: Canary Step: 8/8 SetWeight: 100 ActualWeight: 100 Images: argoproj/rollouts-demo:blue (stable) Replicas: Desired: 5 Current: 5 Updated: 5 Ready: 5 Available: 5 NAME KIND STATUS AGE INFO ⟳ rollouts-demo Rollout ✔ Healthy 4m50s └──# revision:1 └──⧉ rollouts-demo-687d76d795 ReplicaSet ✔ Healthy 4m50s stable ├──□ rollouts-demo-687d76d795-75k57 Pod ✔ Running 4m49s ready:1/1 ├──□ rollouts-demo-687d76d795-bv5zf Pod ✔ Running 4m49s ready:1/1 ├──□ rollouts-demo-687d76d795-jsxg8 Pod ✔ Running 4m49s ready:1/1 ├──□ rollouts-demo-687d76d795-rsgtv Pod ✔ Running 4m49s ready:1/1 └──□ rollouts-demo-687d76d795-xrmrj Pod ✔ Running 4m49s ready:1/1
After the rollout has been created, you can verify that the Status field of the rollout shows Phase: Healthy.
In the Rollout tab, under the Rollouts section, verify that the Status field of the
rollouts-demo
rollout shows as Phase: Healthy.TipAlternatively, you can verify that the rollout is healthy by running the following command:
$ oc argo rollouts status rollouts-demo -n <namespace> 1
- 1
- Specify the namespace where the
Rollout
resource is defined.
Example output
Healthy
You are now ready to perform a canary deployment, with the next update of the Rollout
CR.
3.3. Updating the rollout
When you update the Rollout
custom resource (CR) with modifications to the .spec.template.spec
fields, for example, the container image version, then new pods are created through the ReplicaSet
by using the updated container image version.
Procedure
Simulate the new canary version of the application by modifying the container image deployed in the rollout.
-
In the Administrator perspective of the web console, go to Operators
Installed Operators Red Hat OpenShift GitOps Rollout. -
Select the existing
rollouts-demo
rollout and modify the.spec.template.spec.containers.image
value fromargoproj/rollouts-demo:blue
toargoproj/rollouts-demo:yellow
in the YAML view. Click Save and then click Reload.
The container image deployed in the rollout is modified and the rollout initiates a new canary deployment.
NoteAs per the
setWeight
property defined in the.spec.strategy.canary.steps
field of theRollout
CR, initially 20% of traffic to the route reaches the canary version and the rollout is paused indefinitely until a request for promotion is received.Example route with 20% of traffic directed to the canary version and rollout is paused indefinitely until a request for promotion is specified in the subsequent step
spec: replicas: 5 strategy: canary: 1 steps: 2 - setWeight: 20 3 - pause: {} 4 # (...)
- 1
- The deployment strategy that the rollout must use.
- 2
- The steps for the rollout. This example gradually routes 20%, 40%, 60%, and 80% of traffic to the canary version.
- 3
- The percentage of traffic that must be directed to the canary version. A value of 20 means that 20% of traffic is directed to the canary version.
- 4
- Specification to the Argo Rollouts controller to pause indefinitely until it finds a request for promotion.
-
In the Administrator perspective of the web console, go to Operators
Watch the progression of your rollout by running the following command:
$ oc argo rollouts get rollout rollouts-demo --watch -n <namespace> 1
- 1
- Specify the namespace where the
Rollout
CR is defined.
Example output
Name: rollouts-demo Namespace: spring-petclinic Status: ॥ Paused Message: CanaryPauseStep Strategy: Canary Step: 1/8 SetWeight: 20 ActualWeight: 20 Images: argoproj/rollouts-demo:blue (stable) argoproj/rollouts-demo:yellow (canary) Replicas: Desired: 5 Current: 5 Updated: 1 Ready: 5 Available: 5 NAME KIND STATUS AGE INFO ⟳ rollouts-demo Rollout ॥ Paused 9m51s ├──# revision:2 │ └──⧉ rollouts-demo-6cf78c66c5 ReplicaSet ✔ Healthy 99s canary │ └──□ rollouts-demo-6cf78c66c5-zrgd4 Pod ✔ Running 98s ready:1/1 └──# revision:1 └──⧉ rollouts-demo-687d76d795 ReplicaSet ✔ Healthy 9m51s stable ├──□ rollouts-demo-687d76d795-75k57 Pod ✔ Running 9m50s ready:1/1 ├──□ rollouts-demo-687d76d795-jsxg8 Pod ✔ Running 9m50s ready:1/1 ├──□ rollouts-demo-687d76d795-rsgtv Pod ✔ Running 9m50s ready:1/1 └──□ rollouts-demo-687d76d795-xrmrj Pod ✔ Running 9m50s ready:1/1
The rollout is now in a paused status, because there is no pause duration specified in the rollout’s update strategy configuration.
Repeat the previous step to test the newly deployed version of application and ensure that it is working as expected. For example, verify the application by interacting with the application through the browser and try running tests or observing container logs.
The rollout will remain paused until you advance it to the next step.
After you verify that the new version of the application is working as expected, you can decide whether to continue with promotion or to abort the rollout. Accordingly, follow the instructions in "Promoting the rollout" or "Manually aborting the rollout".
3.4. Promoting the rollout
Because your rollout is now in a paused status, as a cluster administrator, you must now manually promote the rollout to allow it to progress to the next step.
Procedure
Simulate another new canary version of the application by running the following command in the Argo Rollouts CLI:
$ oc argo rollouts promote rollouts-demo -n <namespace> 1
- 1
- Specify the namespace where the
Rollout
resource is defined.
Example output
rollout 'rollouts-demo' promoted
This increases the traffic weight to 40% in the canary version.
Verify that the rollout progresses through the rest of the steps, by running the following command:
$ oc argo rollouts get rollout rollouts-demo -n <namespace> --watch 1
- 1
- Specify the namespace where the
Rollout
resource is defined.
Because the rest of the steps as defined in the
Rollout
CR have set durations, for example,pause: {duration: 45}
, the Argo Rollouts controller waits that duration and then automatically moves to the next step.After all steps are completed successfully, the new
ReplicaSet
object is marked as the stable replica set.Example output
Name: rollouts-demo Namespace: spring-petclinic Status: ✔ Healthy Strategy: Canary Step: 8/8 SetWeight: 100 ActualWeight: 100 Images: argoproj/rollouts-demo:yellow (stable) Replicas: Desired: 5 Current: 5 Updated: 5 Ready: 5 Available: 5 NAME KIND STATUS AGE INFO ⟳ rollouts-demo Rollout ✔ Healthy 14m ├──# revision:2 │ └──⧉ rollouts-demo-6cf78c66c5 ReplicaSet ✔ Healthy 6m5s stable │ ├──□ rollouts-demo-6cf78c66c5-zrgd4 Pod ✔ Running 6m4s ready:1/1 │ ├──□ rollouts-demo-6cf78c66c5-g9kd5 Pod ✔ Running 2m4s ready:1/1 │ ├──□ rollouts-demo-6cf78c66c5-2ptpp Pod ✔ Running 78s ready:1/1 │ ├──□ rollouts-demo-6cf78c66c5-tmk6c Pod ✔ Running 58s ready:1/1 │ └──□ rollouts-demo-6cf78c66c5-zv6lx Pod ✔ Running 47s ready:1/1 └──# revision:1 └──⧉ rollouts-demo-687d76d795 ReplicaSet • ScaledDown 14m
3.5. Manually aborting the rollout
When using a canary deployment, the rollout deploys an initial canary version of the application. You can verify it either manually or programmatically. After you verify the canary version and promote it to stable, the new stable version is made available to all users.
However, sometimes bugs, errors, or deployment issues are discovered in the canary version, and you might want to abort the canary rollout and rollback to a stable version of your application.
Aborting a canary rollout deletes the resources of the new canary version and restores the previous stable version of your application. All network traffic such as ingress, route, or virtual service that was being directed to the canary returns to the original stable version.
The following example procedure deploys a new red
canary version of your application, and then aborts it before it is fully promoted to stable.
Procedure
Update the container image version and and modify the
.spec.template.spec.containers.image
value fromargoproj/rollouts-demo:yellow
toargoproj/rollouts-demo:red
by running the following command in the Argo Rollouts CLI:$ oc argo rollouts set image rollouts-demo rollouts-demo=argoproj/rollouts-demo:red -n <namespace> 1
- 1
- Specify the namespace where the
Rollout
custom resource (CR) is defined.
Example output
rollout "rollouts-demo" image updated
The container image deployed in the rollout is modified and the rollout initiates a new canary deployment.
- Wait for the rollout to reach the paused status.
Verify that the rollout deploys the
rollouts-demo:red
canary version and reaches the paused status by running the following command:$ oc argo rollouts get rollout rollouts-demo --watch -n <namespace> 1
- 1
- Specify the namespace where the
Rollout
CR is defined.
Example output
Name: rollouts-demo Namespace: spring-petclinic Status: ॥ Paused Message: CanaryPauseStep Strategy: Canary Step: 1/8 SetWeight: 20 ActualWeight: 20 Images: argoproj/rollouts-demo:red (canary) argoproj/rollouts-demo:yellow (stable) Replicas: Desired: 5 Current: 5 Updated: 1 Ready: 5 Available: 5 NAME KIND STATUS AGE INFO ⟳ rollouts-demo Rollout ॥ Paused 17m ├──# revision:3 │ └──⧉ rollouts-demo-5747959bdb ReplicaSet ✔ Healthy 75s canary │ └──□ rollouts-demo-5747959bdb-fdrsg Pod ✔ Running 75s ready:1/1 ├──# revision:2 │ └──⧉ rollouts-demo-6cf78c66c5 ReplicaSet ✔ Healthy 9m45s stable │ ├──□ rollouts-demo-6cf78c66c5-zrgd4 Pod ✔ Running 9m44s ready:1/1 │ ├──□ rollouts-demo-6cf78c66c5-2ptpp Pod ✔ Running 4m58s ready:1/1 │ ├──□ rollouts-demo-6cf78c66c5-tmk6c Pod ✔ Running 4m38s ready:1/1 │ └──□ rollouts-demo-6cf78c66c5-zv6lx Pod ✔ Running 4m27s ready:1/1 └──# revision:1 └──⧉ rollouts-demo-687d76d795 ReplicaSet • ScaledDown 17m
Abort the update of the rollout by running the following command:
$ oc argo rollouts abort rollouts-demo -n <namespace> 1
- 1
- Specify the namespace where the
Rollout
CR is defined.
Example output
rollout 'rollouts-demo' aborted
The Argo Rollouts controller deletes the canary resources of the application, and rolls back to the stable version.
Verify that after aborting the rollout, now the canary
ReplicaSet
is scaled to 0 replicas by running the following command:$ oc argo rollouts get rollout rollouts-demo --watch -n <namespace> 1
- 1
- Specify the namespace where the
Rollout
CR is defined.
Example output
Name: rollouts-demo Namespace: spring-petclinic Status: ✖ Degraded Message: RolloutAborted: Rollout aborted update to revision 3 Strategy: Canary Step: 0/8 SetWeight: 0 ActualWeight: 0 Images: argoproj/rollouts-demo:yellow (stable) Replicas: Desired: 5 Current: 5 Updated: 0 Ready: 5 Available: 5 NAME KIND STATUS AGE INFO ⟳ rollouts-demo Rollout ✖ Degraded 24m ├──# revision:3 │ └──⧉ rollouts-demo-5747959bdb ReplicaSet • ScaledDown 7m38s canary ├──# revision:2 │ └──⧉ rollouts-demo-6cf78c66c5 ReplicaSet ✔ Healthy 16m stable │ ├──□ rollouts-demo-6cf78c66c5-zrgd4 Pod ✔ Running 16m ready:1/1 │ ├──□ rollouts-demo-6cf78c66c5-2ptpp Pod ✔ Running 11m ready:1/1 │ ├──□ rollouts-demo-6cf78c66c5-tmk6c Pod ✔ Running 11m ready:1/1 │ ├──□ rollouts-demo-6cf78c66c5-zv6lx Pod ✔ Running 10m ready:1/1 │ └──□ rollouts-demo-6cf78c66c5-mlbsh Pod ✔ Running 4m47s ready:1/1 └──# revision:1 └──⧉ rollouts-demo-687d76d795 ReplicaSet • ScaledDown 24m
The rollout status is marked as
Degraded
indicating that even though the application has rolled back to the previous stable version,yellow
, the rollout is not currently at the wanted version,red
, that was set within the.spec.template.spec.containers.image
field.NoteThe
Degraded
status does not reflect the health of the application. It only indicates that there is a mismatch between the wanted and running container image versions.Update the container image version to the previous stable version,
yellow
, and modify the.spec.template.spec.containers.image
value by running the following command:$ oc argo rollouts set image rollouts-demo rollouts-demo=argoproj/rollouts-demo:yellow -n <namespace> 1
- 1
- Specify the namespace where the
Rollout
CR is defined.
Example output
rollout "rollouts-demo" image updated
The rollout skips the analysis and promotion steps, rolls back to the previous stable version,
yellow
, and fast-tracks the deployment of the stableReplicaSet
.Verify that the rollout status is immediately marked as
Healthy
by running the following command:$ oc argo rollouts get rollout rollouts-demo --watch -n <namespace> 1
- 1
- Specify the namespace where the
Rollout
CR is defined.
Example output
Name: rollouts-demo Namespace: spring-petclinic Status: ✔ Healthy Strategy: Canary Step: 8/8 SetWeight: 100 ActualWeight: 100 Images: argoproj/rollouts-demo:yellow (stable) Replicas: Desired: 5 Current: 5 Updated: 5 Ready: 5 Available: 5 NAME KIND STATUS AGE INFO ⟳ rollouts-demo Rollout ✔ Healthy 63m ├──# revision:4 │ └──⧉ rollouts-demo-6cf78c66c5 ReplicaSet ✔ Healthy 55m stable │ ├──□ rollouts-demo-6cf78c66c5-zrgd4 Pod ✔ Running 55m ready:1/1 │ ├──□ rollouts-demo-6cf78c66c5-2ptpp Pod ✔ Running 50m ready:1/1 │ ├──□ rollouts-demo-6cf78c66c5-tmk6c Pod ✔ Running 50m ready:1/1 │ ├──□ rollouts-demo-6cf78c66c5-zv6lx Pod ✔ Running 50m ready:1/1 │ └──□ rollouts-demo-6cf78c66c5-mlbsh Pod ✔ Running 44m ready:1/1 ├──# revision:3 │ └──⧉ rollouts-demo-5747959bdb ReplicaSet • ScaledDown 46m └──# revision:1 └──⧉ rollouts-demo-687d76d795 ReplicaSet • ScaledDown 63m