LetsEncrypt
Migrating Kubernetes cluster with zero downtime
When a company decides to use Kubernetes clusters in production and maintain high level of availability/SLA, sooner or later time will come to perform a full cluster migration with zero downtime. There are many reasons why a full cluster migration may be required. For example moving to a new hosting platform, implementing zone-redundancy for worker nodes, changing cluster configuration to use managed identity (as opposed to managing the service principal yourself) or simply performing a risky cluster upgrade (AKS 1.17 -> 1.18 changes Ubuntu OS version, 1.18 -> 1.19 changes default container runtime interface). Doing a zero-downtime migration is definitely possible, but requires careful planning.
ReadAutomate Let's Encrypt wildcard certificate deployment to an Azure VM
Automating TLS certificate issuing via Let's Encrypt is very straight-forward in new emerging orchestrators like Kubernetes. Achieving the same on a virtual machine running IIS is still very much in demand, but the process is not well documented and a little bit more difficult to get right.
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