Description:

Blue-Green and Canary deployment are both techniques that can be used to deploy new versions of an application to a Kubernetes cluster, such as Azure Kubernetes Service (AKS).

Blue-Green deployment is a technique in which two identical production environments are maintained, one called "blue" and the other called "green". The active environment, or the one that serves live traffic, is called the "blue" environment. The "green" environment is idle, but ready to take over in case of a problem with the "blue" environment. When a new version of the application is ready to be deployed, it is deployed to the "green" environment first, and then the traffic is switched over to the "green" environment, making it the active environment.

Canary deployment, on the other hand, is a technique in which a new version of an application is deployed to a small subset of the production environment, called a "canary". The canary environment is then monitored for any issues or problems. If everything appears to be working well, the new version of the application is then deployed to the rest of the production environment. Canary deployment allows for a gradual roll-out of a new version of an application, which can minimize the risk of introducing new bugs or problems.

In summary, Blue-Green deployment is a technique for zero-downtime deployment by switching between two identical environments. Canary deployment is a technique for gradually rolling out new versions of an application to a production environment by deploying to a small subset of the environment first. Both techniques can be used to deploy to AKS and other Kubernetes clusters, and it depends on the specific use-case and requirements to determine which technique is most appropriate.
 

Blue-Green Deployment with AKS:

Here is an example of how you can implement Blue-Green deployment on AKS using the Azure CLI:

Create two identical environments (e.g. "blue" and "green") in AKS:

 az aks create -g myResourceGroup -n myAKSCluster-blue --generate-ssh-keys az aks create -g myResourceGroup -n myAKSCluster-green --generate-ssh-keys 

Deploy your application to the "green" environment:

 az aks get-credentials -g myResourceGroup -n myAKSCluster-green kubectl apply -f myApp.yaml 

Create an Azure Load Balancer with a public IP address:

az network lb create -g myResourceGroup -n myLoadBalancer --public-ip-address myPublicIP 

Create a service that uses the load balancer and points to the "green" environment:

kubectl expose deployment myApp --type LoadBalancer --name myService --load-balancer-ip myPublicIP 

When you are ready to deploy a new version of your application, you can deploy it to the "blue" environment, and then switch the traffic over to the "blue" environment:

az aks get-credentials -g myResourceGroup -n myAKSCluster-blue kubectl apply -f myNewApp.yaml kubectl set service myService --selector app=myNewApp 

Canary Deployment with AKS:

Here is an example of how you can implement Canary deployment on AKS using the Azure CLI:

Create a new version of your application and deploy it to a small subset of the production environment:

kubectl apply -f myCanaryApp.yaml 

Use a service mesh such as Istio to route a small percentage of traffic to the canary environment:

kubectl apply -f istio-canary.yaml 

Monitor the canary environment for any issues or problems:

kubectl get pods -l app=myCanaryApp 

If everything appears to be working well, you can then deploy the new version of the application to the rest of the production environment:

kubectl apply -f myNewApp.yaml 

Both Canary and Blue-Green deployment are techniques that can be used to deploy new versions of an application to a Kubernetes cluster, such as Azure Kubernetes Service (AKS).

Advantages of Canary deployment:

• Gradual roll-out: Canary deployment allows for a gradual roll-out of a new version of an application, which can minimize the risk of introducing new bugs or problems.
• Identify issues early: By deploying a new version of the application to a small subset of the production environment first, issues can be identified early, and the roll-out can be halted before it reaches the entire production environment.
• Lower risk: By monitoring the canary environment, you can detect and fix problems before they affect the entire production environment, which reduces the risk of a major issue occurring.
• Reduced downtime: Because the new version is deployed to a small subset of the production environment, the impact of a problem is minimized, which reduces downtime.

Advantages of Blue-Green deployment:

• Zero-downtime: Because traffic is switched over to the new version of the application only after it has been deployed and tested, there is no downtime for users.
• Easy rollback: If a problem is identified with the new version of the application, traffic can be quickly switched back to the previous version, which makes it easy to roll back to a stable version.
• Reduced risk: Because the new version of the application is deployed to a separate environment, the risk of introducing new bugs or problems is minimized.
• Easy testing: The new version of the application can be tested in a separate environment before it is deployed to the production environment, which makes it easier to identify and fix problems.

In summary, Canary deployment is best suited for cases where you want to identify issues early and gradually roll out new features, while Blue-Green deployment is best suited for cases where you want to minimize downtime and have easy rollback. The choice between the two will depend on the specific use-case and requirements of the application and the organization that runs it.

Click to Home