Earlier, in Kubernetes Volumes, we got some understanding of Volumes. This post focuses on practice, learning how to use the three local storage options: emptydir, hostpath, and localvolume. 1. Basic Properties of a PV 1.1 PV Lifecycle PV states: Available: available, not yet bound by any PVC Bound: already bound to a PVC Released: the PVC was deleted, but the resource has not yet been reclaimed Failed: automatic reclamation failed 1.

1. Cluster Planning Prepare three hosts: one Master and two Nodes. Operating system: CentOS 7 Specs: 2 Core 4 GB Docker version: 18.06.3 Kubernetes version: 1.15.3 If you are using a purchased cloud host, open the following ports: 1 2 3 4 5 6 7 8 9 10 11 12

1. Origins Originally, two CoreOS employees, in order to make deploying etcd clusters easier, bound corresponding logical operations to the create, delete, and update events of the etcdCluster object, using Kubernetes to automate etcd cluster management. A few months later, at a KubeCon conference, they shared this approach, which they called Operator, and it received a strong response from the community.

1. Why Helm Is Needed One important design philosophy in Kubernetes is declarative operation. Users change the system by setting the system’s expected state. For example, the current replica count is 2 and it needs to be adjusted to 3. The declarative way is to modify the replica count in

1. Go’s Package Management Mechanisms 1.1 GOPATH GOPATH pulls code with the go get command and places it in the GOPATH directory. The problems with GOPATH are: It cannot manage package versions It uses a global repository, so it cannot isolate projects effectively 1.2 Vendor Starting with version 1.5, Go