May 22, 2021 Docker From entry to practice
Today, Kubernetes supports installation in a variety of environments, including on-premises hosts (Fedora), cloud services (Google GAE, AWS, and so on). However, the quickest way to experience Kubernetes is clearly to start the process locally through Docker.
The following illustration shows the topology of a set of Kubernetes deployed quickly in a single node using Docker.
Kubernetes relies on the Etcd service to maintain the state of all primary nodes.
docker run --net=host -d gcr.io/google_containers/etcd:2.0.9 /usr/local/bin/etcd --addr=127.0.0.1:4001 --bind-addr=0.0.0.0:4001 --data-dir=/var/etcd/data
Start the kubelet.
docker run --net=host -d -v /var/run/docker.sock:/var/run/docker.sock gcr.io/google_containers/hyperkube:v0.17.0 /hyperkube kubelet --api_servers=http://localhost:8080 --v=2 --address=0.0.0.0 --enable_server --hostname_override=127.0.0.1 --config=/etc/kubernetes/manifests
docker run -d --net=host --privileged gcr.io/google_containers/hyperkube:v0.17.0 /hyperkube proxy --master=http://127.0.0.1:8080 --v=2
Access the 8080 port locally and get the following results:
$ curl 127.0.0.1:8080
{
"paths": [
"/api",
"/api/v1beta1",
"/api/v1beta2",
"/api/v1beta3",
"/healthz",
"/healthz/ping",
"/logs/",
"/metrics",
"/static/",
"/swagger-ui/",
"/swaggerapi/",
"/validate",
"/version"
]
}
After all services are started, look at the Docker containers that are actually running locally, and there are several.
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
ee054db2516c gcr.io/google_containers/hyperkube:v0.17.0 "/hyperkube schedule 2 days ago Up 1 days k8s_scheduler.509f29c9_k8s-master-127.0.0.1_default_9941e5170b4365bd4aa91f122ba0c061_e97037f5
3b0f28de07a2 gcr.io/google_containers/hyperkube:v0.17.0 "/hyperkube apiserve 2 days ago Up 1 days k8s_apiserver.245e44fa_k8s-master-127.0.0.1_default_9941e5170b4365bd4aa91f122ba0c061_6ab5c23d
2eaa44ecdd8e gcr.io/google_containers/hyperkube:v0.17.0 "/hyperkube controll 2 days ago Up 1 days k8s_controller-manager.33f83d43_k8s-master-127.0.0.1_default_9941e5170b4365bd4aa91f122ba0c061_1a60106f
30aa7163cbef gcr.io/google_containers/hyperkube:v0.17.0 "/hyperkube proxy -- 2 days ago Up 1 days jolly_davinci
a2f282976d91 gcr.io/google_containers/pause:0.8.0 "/pause" 2 days ago Up 2 days k8s_POD.e4cc795_k8s-master-127.0.0.1_default_9941e5170b4365bd4aa91f122ba0c061_e8085b1f
c060c52acc36 gcr.io/google_containers/hyperkube:v0.17.0 "/hyperkube kubelet 2 days ago Up 1 days serene_nobel
cc3cd263c581 gcr.io/google_containers/etcd:2.0.9 "/usr/local/bin/etcd 2 days ago Up 1 days happy_turing
These services fall into three categories: primary node services, work node services, and other services.