Mapping Azure DevOps Multi-Stage Pipelines to GitHub Actions - Part 1

 Migrating from Azure DevOps to GitHub Actions is mostly about rethinking stages → jobs, and stage dependencies → job dependencies (needs) while keeping environments and deployment isolation intact. This is a bit challanging task as GitHub actions does not support independant varaible groups and environments as in Azure DevOps. In this post let's look at  how a classic multi-stage deployment flow can be represented cleanly in GitHub Actions.

The Source Azure DevOps pipline can be a single env deployment such as below.

Monitor and Profile Memory Usage in a Running .NET Linux Pod in AKS

 Sometimes we need to understand what causes high memeory usages or if any memory leaks in our application setup. When we see pod memeory is not reclaimed for longer intervals, analyzing the usage and diagnosing where exactly is the problem would be useful to fix the issues. Such profiling of memeory, we should be able to do in a running container inside a pod to understand the full details. Let's look at step by step how to profile and monitor memory usage in a .NET app running in a Linux pod in AKS.

Expectaion is to have the ability to monitor live counters as shown below.

Update Deployment Resource Allocation in AKS with Kubectl

 Sometimes we might have to update resource allocations (memory and CPU) in AKS deployed apps without full redeployment. In such cases we can easly use kubectl to patch the deployment so it increase or reduce resources as we need it and gradually apply to running pods by restartting them gracefully. Let's see how.

Handle Nginx Gateway Certificate Refresh While Inplace Upgrade in AKS

 In the post "High Availability Deployment of Nginx Gateway Fabric Replacing Retired Ingress Nginx in AKS - Part 2 - Deploy Nginx-Gateway-Fabric" we hav discussed how to get nginx gateway setup in AKS. This approach works fine for the first install and if you are using true blue green with a fresh AKS cluster. However, when we use componenets such as elastic search  on AKS (which we will discuss in future posts how to setup elastc search on AKS) ,we have to use inplace AKS upgrades, with new node pools in same cluster, as we want to persist the data on elastic. In such inplace AKS upgrade requirements we will have to upgrade cert manager and nginx gateway as well inplace. When we try to do such upgrades to cert-manager and nginx gateway we are running into a issue as decribed below.

The Issue

Immediately after the upgrade or after a time interval, the dataplane pods of nginx gteway will run into a high CPU situation and will try to create pods. These pods will not be able to start properly as it they will not be able to validate the certificates generated. Ideally this situation should have been handled by the control plane (operator) of niginx gateway. however, it does not do that properly.

Adding SnippetsFIlter to HTTPRoute in Nginx Gateway to Implement Proxy Annotations of Retired Ingress Nginx

 We have discussed "Setup Nginx-Gateway Routes and Create Gateway Policies to Map with Ingress Nginx Annotations" in a previous post. However, we have not setup all that were previously set via ingress-nginx annotations, and only partial setup was made using ClientSettingsPolicy and UpstreamSettingsPolicy. Some proxy annotations that we used with ingress-nginx can only be setup by using a SnippetsFilter. 

Such SnippetsFilter is shown below for example.

High Availability Deployment of Nginx Gateway Fabric Replacing Retired Ingress Nginx in AKS - Part 5 - Cleanup Ingress-Nginx from the AKS Cluster

 We have switched traffic from ingress-nginx to nginx-gateway as discussed in the previous blog. The next step is to gent ingress-nginx setup cleaned up from AKS env. This can be done manually. However, when there are mutiple production regions deployed with same deployment, it is easier if we programatically remove all ingress-nginx related routing and setupp, so it can be deployed to all production environments, same way, without issues.

The expectation is to get ingrss nginx removed, and the namespace ingress-nginx also cleaned up from the AKS cluster. Therefore, we can remove the namespace creation yaml as shown below.

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.