High Availability Deployment of Nginx Gateway Fabric Replacing Retired Ingress Nginx in AKS - Part 4 - Switch Traffic from Ingress-Nginx to Nginx-Gateway

 In the part 2 and part 3 of this blog series, we have deployed nginx-gateway in AKS, with required route and policy setup to correctly route to elastic search and kibana deployed in AKS. But we are still have live traffic to elastic search and kibana via the retired ingress-nginx, after the deployment of nginx-gateway also in the same cluster. No as we planned we are going to do the release 2 to get the traffic switch from retired ingress-nginx to new nginx-gateway deployed in AKS.

The expectation is to have kibana and elastic host names to resolve to private IP of the nginx-gateway loadbalancer as shown below, and the ability to use elastic search with the url, using nginx-gateway.

High Availability Deployment of Nginx Gateway Fabric Replacing Retired Ingress Nginx in AKS - Part 3 - Setup Nginx-Gateway Routes and Create Gateway Policies to Map with Ingress Nginx Annotations

We have discussed how to deploy nginx-gateway in part 2 of this blog series.  As the nginx-gateway is deployed and ready now, we can start setting up HTTP routes, so that it is ready to replace the ingress-nginx (retired) routes already working in the AKS cluster. The example in this blog uses, routes to AKS hosted elastic search, so there are two routes, the kibana dashboard route and the elastic search route used by the apps. The currrent routes use a private DNS, and a private IP within Azure vNET. We have used a new private IP for nginx gateway in deploy nginx-gateway in part 2 , so that current retired  ingress-nginx internal loadbalancer is not affected, while we setup nginx-gateway (uses another private IP for loadbalancer of gateway), making them both available in AKS cluster. Therefore, setting up same host names for gateway routes will not cause issues in existing ingress-nginx setup. After this step of setting up routes, we will have both ingress-nginx (retired) and nginx-gateway with routes, working in same cluster, but live traffic will be still using ingress-nginx.

The expectation is to have routes using nginx-gateway is setup for ealstic search and kibana as shown below.

High Availability Deployment of Nginx Gateway Fabric Replacing Retired Ingress Nginx in AKS - Part 2 - Deploy Nginx-Gateway-Fabric

In part 1 "High Availability Deployment of Nginx Gateway Fabric Replacing Retired Ingress Nginx in AKS - Part 1 - Plan for Smooth Transition", we have discussed the plan to transtion from retired ingess-nginx to nginx-gateway, for an AKS cluster where we have hosted elatic search.  In this post let's look at steps necessary to deploy nginx-gateway.

The expection is to have successfully deployed high available nginx-gateway with nginx gateway fabric.

High Availability Deployment of Nginx Gateway Fabric Replacing Retired Ingress Nginx in AKS - Part 1 - Plan for Smooth Transition

 We have discussed setting up ingress-nginx as ingress controller for AKS previously. Ingress-nginx for kubernetes is retiring in March 2026 as announced here in github and in kubernetes documentation. Gateway API is the recommended replacement for ingress-nginx and Nginx Gateway Fabric is an implementation of Gateway API by Nginx. When you have true blue-green deployments with new AKS cluster getting created at each deployment, transitioning from ingress-nginx to nginx gateway fabric is relatively simpler, and we can discuss that in the last blog of this blob post series. However, when you have a single AKS cluster (situations such as hosting elastic search on AKS demands, we use only a single AKS cluster - we will discuss this topic in a later blog series), where blue-green deployments happen using node pools and cluster upgrades as inplace upgrades, the transtion needs to be done over multiple releases to achive zero down time deployments for production. In this blog, let's plan how we can get the transition done in a step by step manner.

The expectation is to get nginx-gateway setup as shown below, so that HTTP routes can be setup via the gateway.

AKS Pod Memory Usage Percentage Chart Using Managed Prometheus Data

 In previous post we have discussed "Setup Managed Prometheus for AKS via Terraform" and "Enable Windows Data Scraping for AKS Managed Prometheus with Azure Managed Grafana". Understanding memory usage % for each application pod running in AKS, and setup alerts for higher uasge is useful to identify memory allocation requirements or any memory leaks in applications. Let's look at how to setup a chart in Azure Managed Grafana using AKS managed prometheus data.

The expectation is to get a chart as shown below.

Use Terraform to Switch Azure Key Vault to Use RBAC Permisions from Access Policies Without a Downtime for Applications/Users

 For Azure Key Vaults access policies based permision setup is now legacy and all key vaults will have to use Azure RBAC permisions eventually for data access permisions according to offcial Microsft documentation here. Using terraform we can setup the changes. However, we have to be carefull about the switching to RBAC from access policies in production scenarios to avoid interptions to applications. Taking two step approach, first set RBAC permisions and in a next release performing switch to RBAC for key vault will help the transtion to be smooth. Let's look at how to setup this requirement with terraform.

The expectation is to have a keyvault setup with RBAC permisions as shown below.

 

Using Remote Terraform State

 Sometimes resources common to multiple diffrent setups might need to be created with a common terraform code. In such cases the commeo terraform resources may need to be reffered with its state in  other terraform code. For this requirement we can use terraform remote state. Let's see how we can use terraform remote state step by step in this post.

The expectation is to refer to the Azure resources in remote terraform state as shown below. Here you can see we have reffered to the resource group name and location, and to log analytics workspace id from remote state.

Access Private Url within Azure vNet with Azure Pipeline Microsoft Hosted Pipeline Agent via AKS pod in the vNet

If we are using Microsoft hosted agents for Azure pipelines to deploy Azure infrastucture and need to access vNet protected urls of services deployed, we can use a pod in AKS cluster within same vNet, as a jump host. This gives us access endpoints in vNet and ability to resolve DNS defined in private DNS zones of the vNet. Let's look at staep by step how to achive this goal, while using a Microsoft hosted agent in Azure pipelines.

The expectation is to access url such as 
http://es-search.sh.aks.ch-demo-dev-euw-002.net/demoindex001/_count  so AKS hosted elastic seach is accessed via a AKS pod and get the results to the pipeline agent as shown below. Since microsoft hosted agent is outside the vNET it cannot directly reach this elastc search (deployed in AKS) url.