How do you deploy a feature with zero downtime in Kubernetes?

1.	How do you deploy a feature with zero downtime in Kubernetes?
Answer» By default Deployment in Kubernetes using RollingUpdate as a strategy. Let's say we have an EXAMPLE that CREATES a deployment in Kubernetes kubectl run nginx --IMAGE=nginx *# creates a deployment* ○ → kubectl get deploy NAME DESIRED CURRENT UP-TO-DATE AVAILABLE AGE nginx 1 1 1 0 7s Now let’s assume we are going to update the nginx image kubectl set image deployment nginx nginx=nginx:1.15 *# updates the image* Now when we check the replica sets kubectl get replicasets *# get replica setsNAME DESIRED CURRENT READY AGE nginx-65899c769f 0 0 0 7m nginx-6c9655f5bb 1 1 1 13s From the above, we can notice that one more replica set was added and then the other replica set was brought down kubectl rollout status deployment nginx # check the status of a deployment* rollout kubectl rollout history deployment nginx *# check the revisions in a deployment* ○ → kubectl rollout history deployment nginx deployment.extensions/nginx REVISION CHANGE-CAUSE 1 <NONE> 2 <none>

Answer»

By default Deployment in Kubernetes using RollingUpdate as a strategy. Let's say we have an EXAMPLE that CREATES a deployment in Kubernetes

kubectl run nginx --IMAGE=nginx # creates a deployment ○ → kubectl get deploy NAME DESIRED CURRENT UP-TO-DATE AVAILABLE AGE nginx 1 1 1 0 7s

Now let’s assume we are going to update the nginx image

kubectl set image deployment nginx nginx=nginx:1.15 # updates the image

Now when we check the replica sets

kubectl get replicasets # get replica setsNAME DESIRED CURRENT READY AGE nginx-65899c769f 0 0 0 7m nginx-6c9655f5bb 1 1 1 13s

From the above, we can notice that one more replica set was added and then the other replica set was brought down

kubectl rollout status deployment nginx

# check the status of a deployment rollout

kubectl rollout history deployment nginx

# check the revisions in a deployment

○ → kubectl rollout history deployment nginx deployment.extensions/nginx REVISION CHANGE-CAUSE 1 <NONE> 2 <none>

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