krew VS cert-manager

Authenticating with Kyma is a (in my opinion) unnecessary challenge as it leverages the OIDC-login plugin for kubectl. You find a description of the setup here. This works fine when on a Mac but can give you some headaches on a Windows and on Linux machine especially when combined with restrictive setups in corporate environments. For Windows I can only recommend installing krew via chocolatey and then install the OIDC plugin via kubectl krew install oidc-login. At least for me that was the only way to get this working on Windows.

( set -x; cd "$(mktemp -d)" && OS="$(uname | tr '[:upper:]' '[:lower:]')" && ARCH="$(uname -m | sed -e 's/x86_64/amd64/' -e 's/\(arm\)\(64\)\?.*/\1\2/' -e 's/aarch64$/arm64/')" && KREW="krew-${OS}_${ARCH}" && curl -fsSLO "https://github.com/kubernetes-sigs/krew/releases/download/v0.4.4/krew-linux_amd64.tar.gz" && tar zxvf "${KREW}.tar.gz" && ./"${KREW}" install krew )

Krew is a way to manage plugins for Kubernetes. For more info, check out the following link: https://krew.sigs.k8s.io/

I plan on getting it added as a krew plugin, so watch this space.

Krew is a plugin manager maintained by the Kubernetes Special Interest Group (SIG) CLI community. Krew makes it easy to use kubectl plugins and helps you discover, install, and manage them on your machine. It is similar to tools like apt, dnf, or brew. Today, over 200 kubectl plugins are available on Krew - and that number is only increasing. Some projects are actively used and some get deprecated over time, but are still accessible via Krew.

kubectl plugins can be installed in numerous ways, the easiest way would be to install the official plugin manager called krew.

( set -x; cd "$(mktemp -d)" && OS="$(uname | tr '[:upper:]' '[:lower:]')" && ARCH="$(uname -m | sed -e 's/x86_64/amd64/' -e 's/\(arm\)\(64\)\?.*/\1\2/' -e 's/aarch64$/arm64/')" && KREW="krew-${OS}_${ARCH}" && curl -fsSLO "https://github.com/kubernetes-sigs/krew/releases/latest/download/${KREW}.tar.gz" && tar zxvf "${KREW}.tar.gz" && ./"${KREW}" install krew )

-- What is Krew?

cert-manager

The second one is a combination of tools: External DNS, cert-manager, and NGINX ingress. Using these as a stack, you can quickly deploy an application, making it available through a DNS with a TLS without much effort via simple annotations. When I first discovered External DNS, I was amazed at its quality.

On top of its core components, SpinKube depends on cert-manager. cert-Manager is responsible for provisioning and managing TLS certificates that are used by the admission webhook system of the Spin Operator. Let’s install cert-manager and KWasm using the commands shown here:

terraform { required_providers { kubectl = { source = "gavinbunney/kubectl" version = "1.14.0" } } } # The reference to the current project or a AWS project data "google_client_config" "provider" {} # The reference to the current cluster or EKS data "google_container_cluster" "my_cluster" { name = var.cluster_name location = var.cluster_location } # We configure the kubectl provider to use those values for authenticating provider "kubectl" { host = data.google_container_cluster.my_cluster.endpoint token = data.google_client_config.provider.access_token cluster_ca_certificate = base64decode(data.google_container_cluster.my_cluster.master_auth[0].cluster_ca_certificate) } #Download the multiple manifests file. data "http" "cert_manager_crds" { url = "https://github.com/cert-manager/cert-manager/releases/download/v${var.cert_manager_version}/cert-manager.crds.yaml" } data "kubectl_file_documents" "cert_manager_crds" { content = data.http.cert_manager_crds.response_body lifecycle { precondition { condition = 200 == data.http.cert_manager_crds.status_code error_message = "Status code invalid" } } } # We use the for_each or else this kubectl_manifest will only import the first manifest in the file. resource "kubectl_manifest" "cert_manager_crds" { for_each = data.kubectl_file_documents.cert_manager_crds.manifests yaml_body = each.value }

SSL certificates thanks to Cloudflare and cert-manager

kubectl apply -f https://github.com/cert-manager/cert-manager/releases/download/${CERT_MANAGER_VERSION}/cert-manager.crds.yaml

put the Sub-CA inside hashicorp vault to be used for automatic signing of services like https://cert-manager.io/ inside our k8s clusters.

install-cert-manager: desc: Install cert-manager deps: - init-cluster cmds: - kubectl apply -f https://github.com/cert-manager/cert-manager/releases/download/{{.CERT_MANAGER_VERSION}}/cert-manager.yaml - echo "Waiting for cert-manager to be ready" && sleep 25 status: - kubectl -n cert-manager get pods | grep Running | wc -l | grep -q 3

I've been pretty frustrated with how private CAs are supported. Your private root CA can be maliciously used to MITM every domain on the Internet, even though you intend to use it for only a couple domain names. Most people forget to set Name Constraints when they create these and many helper tools lack support [1][2]. Worse, browser support for Name Constraints has been slow [3] and support isn't well tracked [4]. Public CAs give you certificate transparency and you can subscribe to events to detect mis-issuance. Some hosted private CAs like AWS's offer logs [5], but DIY setups don't.

Even still, there are a lot of folks happily using private CAs, they aren't the target audience for this initial release.

[1] https://github.com/FiloSottile/mkcert/issues/302

[2] https://github.com/cert-manager/cert-manager/issues/3655

[3] https://alexsci.com/blog/name-non-constraint/

[4] https://github.com/Netflix/bettertls/issues/19

[5] https://docs.aws.amazon.com/privateca/latest/userguide/secur...

the Cert Manager