Kubectl Rollout
Kubectl Rollout
Rollout
Let us take a look at the current deployments.
pradeep@learnk8s$ kubectl get deployment
NAME READY UP-TO-DATE AVAILABLE AGE
kodekloud 4/4 4 4 13d
To manage the rollout of a resource like deployments, kubernetes provides the rollout option, with which we can view rollout history, see the status of the rollout and even undo a previous rollout.
Here is the detailed help information.
pradeep@learnk8s$ kubectl rollout -h
Manage the rollout of a resource.
Valid resource types include:
* deployments
* daemonsets
* statefulsets
Examples:
# Rollback to the previous deployment
kubectl rollout undo deployment/abc
# Check the rollout status of a daemonset
kubectl rollout status daemonset/foo
Available Commands:
history View rollout history
pause Mark the provided resource as paused
restart Restart a resource
resume Resume a paused resource
status Show the status of the rollout
undo Undo a previous rollout
Usage:
kubectl rollout SUBCOMMAND [options]
Use "kubectl <command> --help" for more information about a given command.
Use "kubectl options" for a list of global command-line options (applies to all commands).
Let us use this option to view the history of our kodekloud deployment.
pradeep@learnk8s$ kubectl rollout history deployment kodekloud
deployment.apps/kodekloud
REVISION CHANGE-CAUSE
1 <none>
3 <none>
4 <none>
We do see that there are multiple revisions to this kodekloud deployment, but we do not see any CHANGE-CAUSE.
Even in the description, we do see only one line related to deployment.kubernetes.io/revision. Pay attention to the Annotations section.
pradeep@learnk8s$ kubectl describe deployments.apps
Name: kodekloud
Namespace: default
CreationTimestamp: Tue, 15 Feb 2022 12:43:38 +0530
Labels: app=kodekloud
Annotations: deployment.kubernetes.io/revision: 4
Selector: app=kodekloud
Replicas: 4 desired | 4 updated | 4 total | 4 available | 0 unavailable
StrategyType: Recreate
MinReadySeconds: 0
Pod Template:
Labels: app=kodekloud
Containers:
webapp-color:
Image: kodekloud/webapp-color:v2
Port: <none>
Host Port: <none>
Environment: <none>
Mounts: <none>
Volumes: <none>
Conditions:
Type Status Reason
---- ------ ------
Progressing True NewReplicaSetAvailable
Available True MinimumReplicasAvailable
OldReplicaSets: <none>
NewReplicaSet: kodekloud-8477b7849 (4/4 replicas created)
Events: <none>
Create a new deployment
pradeep@learnk8s$ cat nginx-deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
name: nginx-deployment
labels:
app: nginx
spec:
replicas: 3
selector:
matchLabels:
app: nginx
template:
metadata:
labels:
app: nginx
spec:
containers:
- name: nginx
image: nginx:1.20
ports:
- containerPort: 80
pradeep@learnk8s$ kubectl apply -f nginx-deployment.yaml
deployment.apps/nginx-deployment created
pradeep@learnk8s$ kubectl get deployments.apps
NAME READY UP-TO-DATE AVAILABLE AGE
kodekloud 4/4 4 4 13d
nginx-deployment 3/3 3 3 31s
pradeep@learnk8s$ kubectl describe deployments.apps nginx-deployment
Name: nginx-deployment
Namespace: default
CreationTimestamp: Tue, 01 Mar 2022 06:05:50 +0530
Labels: app=nginx
Annotations: deployment.kubernetes.io/revision: 1
Selector: app=nginx
Replicas: 3 desired | 3 updated | 3 total | 3 available | 0 unavailable
StrategyType: RollingUpdate
MinReadySeconds: 0
RollingUpdateStrategy: 25% max unavailable, 25% max surge
Pod Template:
Labels: app=nginx
Containers:
nginx:
Image: nginx:1.20
Port: 80/TCP
Host Port: 0/TCP
Environment: <none>
Mounts: <none>
Volumes: <none>
Conditions:
Type Status Reason
---- ------ ------
Available True MinimumReplicasAvailable
Progressing True NewReplicaSetAvailable
OldReplicaSets: <none>
NewReplicaSet: nginx-deployment-7b96fbf5d8 (3/3 replicas created)
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Warning ReplicaSetCreateError 33s deployment-controller Failed to create new replica set "nginx-deployment-7b96fbf5d8": Unauthorized
Normal ScalingReplicaSet 33s deployment-controller Scaled up replica set nginx-deployment-7b96fbf5d8 to 3
Update Deployment (using Kubectl Set)
Earlier we have used kubectl edit to make changes to an existing deployment.
Here we will explore another option kubectl set.
pradeep@learnk8s$ kubectl set -h
Configure application resources.
These commands help you make changes to existing application resources.
Available Commands:
env Update environment variables on a pod template
image Update the image of a pod template
resources Update resource requests/limits on objects with pod templates
selector Set the selector on a resource
serviceaccount Update the service account of a resource
subject Update the user, group, or service account in a role binding or cluster role binding
Usage:
kubectl set SUBCOMMAND [options]
Use "kubectl <command> --help" for more information about a given command.
Use "kubectl options" for a list of global command-line options (applies to all commands).
Let us set the image for our nginx-deployment to a new version 1.21.
pradeep@learnk8s$ kubectl set image deployment/nginx-deployment nginx=nginx:1.21
deployment.apps/nginx-deployment image updated
We can see the rollout status like this, using the kubectl rollout status command.
pradeep@learnk8s$ kubectl rollout status deployment/nginx-deployment
deployment "nginx-deployment" successfully rolled out
Describe the deployment
pradeep@learnk8s$ kubectl describe deployments.apps nginx-deployment
Name: nginx-deployment
Namespace: default
CreationTimestamp: Tue, 01 Mar 2022 06:05:50 +0530
Labels: app=nginx
Annotations: deployment.kubernetes.io/revision: 2
Selector: app=nginx
Replicas: 3 desired | 3 updated | 3 total | 3 available | 0 unavailable
StrategyType: RollingUpdate
MinReadySeconds: 0
RollingUpdateStrategy: 25% max unavailable, 25% max surge
Pod Template:
Labels: app=nginx
Containers:
nginx:
Image: nginx:1.21
Port: 80/TCP
Host Port: 0/TCP
Environment: <none>
Mounts: <none>
Volumes: <none>
Conditions:
Type Status Reason
---- ------ ------
Available True MinimumReplicasAvailable
Progressing True NewReplicaSetAvailable
OldReplicaSets: <none>
NewReplicaSet: nginx-deployment-5778cd94ff (3/3 replicas created)
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Warning ReplicaSetCreateError 10m deployment-controller Failed to create new replica set "nginx-deployment-7b96fbf5d8": Unauthorized
Normal ScalingReplicaSet 10m deployment-controller Scaled up replica set nginx-deployment-7b96fbf5d8 to 3
Normal ScalingReplicaSet 3m18s deployment-controller Scaled up replica set nginx-deployment-5778cd94ff to 1
Normal ScalingReplicaSet 3m12s deployment-controller Scaled down replica set nginx-deployment-7b96fbf5d8 to 2
Normal ScalingReplicaSet 3m12s deployment-controller Scaled up replica set nginx-deployment-5778cd94ff to 2
Normal ScalingReplicaSet 3m10s deployment-controller Scaled down replica set nginx-deployment-7b96fbf5d8 to 1
Normal ScalingReplicaSet 3m10s deployment-controller Scaled up replica set nginx-deployment-5778cd94ff to 3
Normal ScalingReplicaSet 3m3s deployment-controller Scaled down replica set nginx-deployment-7b96fbf5d8 to 0
