Many applications rely on configuration which is used during either application initialization or runtime. Most times, there is a requirement to adjust values assigned to configuration parameters. ConfigMaps are a Kubernetes mechanism that let you inject configuration data into application pods. The ConfigMap concept allow you to decouple configuration artifacts from image content to keep containerized applications portable. For example, you can download and run the same container image to spin up containers for the purposes of local development, system test, or running a live end-user workload.

Production-Grade Container Orchestration

Production-Grade Container Orchestration

FEATURE STATE: Kubernetes v1.19 [stable] Seccomp stands for secure computing mode and has been a feature of the Linux kernel since version 2.6.12. It can be used to sandbox the privileges of a process, restricting the calls it is able to make from userspace into the kernel. Kubernetes lets you automatically apply seccomp profiles loaded onto a node to your Pods and containers. Identifying the privileges required for your workloads can be difficult.

This command initializes a Kubernetes control plane node. Run this command in order to set up the Kubernetes control plane Synopsis Run this command in order to set up the Kubernetes control plane The "init" command executes the following phases: preflight Run pre-flight checks certs Certificate generation /ca Generate the self-signed Kubernetes CA to provision identities for other Kubernetes components /apiserver Generate the certificate for serving the Kubernetes API /apiserver-kubelet-client Generate the certificate for the API server to connect to kubelet /front-proxy-ca Generate the self-signed CA to provision identities for front proxy /front-proxy-client Generate the certificate for the front proxy client /etcd-ca Generate the self-signed CA to provision identities for etcd /etcd-server Generate the certificate for serving etcd /etcd-peer Generate the certificate for etcd nodes to communicate with each other /etcd-healthcheck-client Generate the certificate for liveness probes to healthcheck etcd /apiserver-etcd-client Generate the certificate the apiserver uses to access etcd /sa Generate a private key for signing service account tokens along with its public key kubeconfig Generate all kubeconfig files necessary to establish the control plane and the admin kubeconfig file /admin Generate a kubeconfig file for the admin to use and for kubeadm itself /super-admin Generate a kubeconfig file for the super-admin /kubelet Generate a kubeconfig file for the kubelet to use *only* for cluster bootstrapping purposes /controller-manager Generate a kubeconfig file for the controller manager to use /scheduler Generate a kubeconfig file for the scheduler to use etcd Generate static Pod manifest file for local etcd /local Generate the static Pod manifest file for a local, single-node local etcd instance control-plane Generate all static Pod manifest files necessary to establish the control plane /apiserver Generates the kube-apiserver static Pod manifest /controller-manager Generates the kube-controller-manager static Pod manifest /scheduler Generates the kube-scheduler static Pod manifest kubelet-start Write kubelet settings and (re)start the kubelet upload-config Upload the kubeadm and kubelet configuration to a ConfigMap /kubeadm Upload the kubeadm ClusterConfiguration to a ConfigMap /kubelet Upload the kubelet component config to a ConfigMap upload-certs Upload certificates to kubeadm-certs mark-control-plane Mark a node as a control-plane bootstrap-token Generates bootstrap tokens used to join a node to a cluster kubelet-finalize Updates settings relevant to the kubelet after TLS bootstrap /enable-client-cert-rotation Enable kubelet client certificate rotation addon Install required addons for passing conformance tests /coredns Install the CoreDNS addon to a Kubernetes cluster /kube-proxy Install the kube-proxy addon to a Kubernetes cluster show-join-command Show the join command for control-plane and worker node kubeadm init [flags] Options --apiserver-advertise-address string The IP address the API Server will advertise it's listening on.

Kubernetes nodes come pre-populated with a standard set of labels. You can also set your own labels on nodes, either through the kubelet configuration or using the Kubernetes API. Preset labels The preset labels that Kubernetes sets on nodes are: kubernetes.io/arch kubernetes.io/hostname kubernetes.io/os node.kubernetes.io/instance-type (if known to the kubelet – Kubernetes may not have this information to set the label) topology.kubernetes.io/region (if known to the kubelet – Kubernetes may not have this information to set the label) topology.

Synopsis Set the latest last-applied-configuration annotations by setting it to match the contents of a file. This results in the last-applied-configuration being updated as though 'kubectl apply -f<file> ' was run, without updating any other parts of the object. kubectl apply set-last-applied -f FILENAME Examples # Set the last-applied-configuration of a resource to match the contents of a file kubectl apply set-last-applied -f deploy.yaml # Execute set-last-applied against each configuration file in a directory kubectl apply set-last-applied -f path/ # Set the last-applied-configuration of a resource to match the contents of a file; will create the annotation if it does not already exist kubectl apply set-last-applied -f deploy.

Before you begin Some steps in this page use the jq tool. If you don't have jq, you can install it via your operating system's software sources, or fetch it from https://jqlang.github.io/jq/. Some steps also involve installing curl, which can be installed via your operating system's software sources. A subset of the kubelet's configuration parameters may be set via an on-disk config file, as a substitute for command-line flags. Providing parameters via a config file is the recommended approach because it simplifies node deployment and configuration management.

This page describes the CoreDNS upgrade process and how to install CoreDNS instead of kube-dns. Before you begin You need to have a Kubernetes cluster, and the kubectl command-line tool must be configured to communicate with your cluster. It is recommended to run this tutorial on a cluster with at least two nodes that are not acting as control plane hosts. If you do not already have a cluster, you can create one by using minikube or you can use one of these Kubernetes playgrounds:

Production-Grade Container Orchestration