這是一篇 K8S 的 HelloWorld,在學習K8S官方文件時搭建環境搭建的一個記錄，照著文件下來還是比較順利的。
一、安裝kubectl
下載 kubectl
curl -LO "https://dl.k8s.io/release/$(curl -L -s https://dl.k8s.io/release/stable.txt)/bin/linux/amd64/kubectl"
下載 checksum
curl -LO "https://dl.k8s.io/$(curl -L -s https://dl.k8s.io/release/stable.txt)/bin/linux/amd64/kubectl.sha256"
檢查sha265sum
arvin@ubuntu:~$ echo "$(<kubectl.sha256) kubectl" | sha256sum --check
kubectl: OK
安裝
sudo install -o root -g root -m 0755 kubectl /usr/local/bin/kubectl
安裝結果
arvin@ubuntu:~$ kubectl version --client
Client Version: version.Info{Major:"1", Minor:"21", GitVersion:"v1.21.1", GitCommit:"5e58841cce77d4bc13713ad2b91fa0d961e69192", GitTreeState:"clean", BuildDate:"2021-05-12T14:18:45Z", GoVersion:"go1.16.4", Compiler:"gc", Platform:"linux/amd64"}
二、安裝minikube
minikube是本地的Kubernetes，致力於使Kubernetes易於學習和開發。
下載minikube
curl -LO https://storage.googleapis.com/minikube/releases/latest/minikube-linux-amd64
安裝
sudo install minikube-linux-amd64 /usr/local/bin/minikube
三、啟動minikube
minikube start
四、碰到的問題
1.提示docker 驅動不能與管理員許可權一起使用
arvin@ubuntu:~$ sudo minikube start
? minikube v1.20.0 on Ubuntu 20.10
✨ Automatically selected the docker driver. Other choices: none, ssh
? The "docker" driver should not be used with root privileges.
? If you are running minikube within a VM, consider using --driver=none:
? https://minikube.sigs.k8s.io/docs/reference/drivers/none/❌ Exiting due to DRV_AS_ROOT: The "docker" driver should not be used with root privileges.
2.提示docker 沒有許可權
arvin@ubuntu:~$ minikube start
? minikube v1.20.0 on Ubuntu 20.10
? Unable to pick a default driver. Here is what was considered, in preference order:
▪ podman: Not installed: exec: "podman": executable file not found in $PATH
▪ virtualbox: Not installed: unable to find VBoxManage in $PATH
▪ vmware: Not installed: exec: "docker-machine-driver-vmware": executable file not found in $PATH
▪ docker: Not healthy: "docker version --format {{.Server.Os}}-{{.Server.Version}}" exit status 1: Got permission denied while trying to connect to the Docker daemon socket at unix:///var/run/docker.sock: Get http://%2Fvar%2Frun%2Fdocker.sock/v1.24/version: dial unix /var/run/docker.sock: connect: permission denied
▪ kvm2: Not installed: exec: "virsh": executable file not found in $PATH❌ Exiting due to DRV_NOT_DETECTED: No possible driver was detected. Try specifying --driver, or see https://minikube.sigs.k8s.io/docs/start/
查閱docker 手冊
The docker daemon binds to a Unix socket instead of a TCP port. By
default that Unix socket is owned by the user root and other users can
only access it using sudo. The docker daemon always runs as the root
user.If you don’t want to use sudo when you use the docker command, create
a Unix group called docker and add users to it. When the docker daemon
starts, it makes the ownership of the Unix socket read/writable by the
docker group.
解決辦法
arvin@ubuntu:~$ sudo groupadd docker #新增docker使用者組
groupadd: group 'docker' already exists
arvin@ubuntu:~$ sudo gpasswd -a $USER docker #將登陸使用者加入到docker使用者組中
Adding user arvin to group docker
arvin@ubuntu:~$ newgrp docker #更新使用者組
五、執行minikube
成功啟動
arvin@ubuntu:~$ minikube start
? minikube v1.20.0 on Ubuntu 20.10
✨ Automatically selected the docker driver. Other choices: none, ssh
? Starting control plane node minikube in cluster minikube
? Pulling base image ...
? Downloading Kubernetes v1.20.2 preload ...
> preloaded-images-k8s-v10-v1...: 491.71 MiB / 491.71 MiB 100.00% 3.31 MiB
> index.docker.io/kicbase/sta...: 358.10 MiB / 358.10 MiB 100.00% 1.39 MiB
❗ minikube was unable to download gcr.io/k8s-minikube/kicbase:v0.0.22, but successfully downloaded kicbase/stable:v0.0.22 as a fallback image
? Creating docker container (CPUs=2, Memory=2200MB) ...
❗ This container is having trouble accessing https://k8s.gcr.io
? To pull new external images, you may need to configure a proxy: https://minikube.sigs.k8s.io/docs/reference/networking/proxy/
? Preparing Kubernetes v1.20.2 on Docker 20.10.6 ...
▪ Generating certificates and keys ...
▪ Booting up control plane ...
▪ Configuring RBAC rules ...
? Verifying Kubernetes components...
▪ Using image gcr.io/k8s-minikube/storage-provisioner:v5
? Enabled addons: storage-provisioner, default-storageclass
? Done! kubectl is now configured to use "minikube" cluster and "default" namespace by default
檢視kuberners 狀態
minikube dashboard --url
? Verifying dashboard health ...
? Launching proxy ...
? Verifying proxy health ...
http://127.0.0.1:34235/api/v1/namespaces/kubernetes-dashboard/services/http:kubernetes-dashboard:/proxy/
六、部署Demo
建立一個develpment
kubectl create deployment hello-minikube --image=k8s.gcr.io/echoserver:1.4
kubectl expose deployment hello-minikube --type=NodePort --port=8080
arvin@ubuntu:~$ kubectl get services hello-minikube
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
hello-minikube NodePort 10.96.129.107 <none> 8080:31559/TCP 46s
arvin@ubuntu:~$ minikube service hello-minikube
|-----------|----------------|-------------|---------------------------|
| NAMESPACE | NAME | TARGET PORT | URL |
|-----------|----------------|-------------|---------------------------|
| default | hello-minikube | 8080 | http://192.168.49.2:30064 |
|-----------|----------------|-------------|---------------------------|
? Opening service default/hello-minikube in default browser...
發現網頁無法訪問
檢視pod資訊
arvin@ubuntu:~$ kubectl get pods -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
hello-minikube-6ddfcc9757-njfpc 0/1 ImagePullBackOff 0 13m 172.17.0.5 minikube <none> <none>
發現處於imagepullbackoff 狀態
檢視pod 詳細描述
arvin@ubuntu:~$ kubectl describe pod
Name: hello-minikube-6ddfcc9757-njfpc
Namespace: default
Priority: 0
Node: minikube/192.168.49.2
Start Time: Wed, 19 May 2021 00:38:52 +0800
Labels: app=hello-minikube
pod-template-hash=6ddfcc9757
Annotations: <none>
Status: Pending
IP: 172.17.0.5
IPs:
IP: 172.17.0.5
Controlled By: ReplicaSet/hello-minikube-6ddfcc9757
Containers:
echoserver:
Container ID:
Image: k8s.gcr.io/echoserver:1.4
Image ID:
Port: <none>
Host Port: <none>
State: Waiting
Reason: ImagePullBackOff
Ready: False
Restart Count: 0
Environment: <none>
Mounts:
/var/run/secrets/kubernetes.io/serviceaccount from default-token-9rdjm (ro)
Conditions:
Type Status
Initialized True
Ready False
ContainersReady False
PodScheduled True
Volumes:
default-token-9rdjm:
Type: Secret (a volume populated by a Secret)
SecretName: default-token-9rdjm
Optional: false
QoS Class: BestEffort
Node-Selectors: <none>
Tolerations: node.kubernetes.io/not-ready:NoExecute op=Exists for 300s
node.kubernetes.io/unreachable:NoExecute op=Exists for 300s
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal Scheduled 15m default-scheduler Successfully assigned default/hello-minikube-6ddfcc9757-njfpc to minikube
Normal Pulling 12m (x4 over 15m) kubelet Pulling image "k8s.gcr.io/echoserver:1.4"
Warning Failed 12m (x4 over 14m) kubelet Failed to pull image "k8s.gcr.io/echoserver:1.4": rpc error: code = Unknown desc = Error response from daemon: Get https://k8s.gcr.io/v2/: net/http: request canceled while waiting for connection (Client.Timeout exceeded while awaiting headers)
Warning Failed 12m (x4 over 14m) kubelet Error: ErrImagePull
Warning Failed 12m (x6 over 14m) kubelet Error: ImagePullBackOff
Normal BackOff 4m56s (x35 over 14m) kubelet Back-off pulling image "k8s.gcr.io/echoserver:1.4"
發現是缺少映象
minikube ssh
docker images
arvin@ubuntu:~$ minikube ssh
Last login: Tue May 18 16:55:58 2021 from 192.168.49.1
docker@minikube:~$ docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
gcr.io/k8s-minikube/storage-provisioner v5 6e38f40d628d 7 weeks ago 31.5MB
k8s.gcr.io/kube-proxy v1.20.2 43154ddb57a8 4 months ago 118MB
k8s.gcr.io/kube-controller-manager v1.20.2 a27166429d98 4 months ago 116MB
k8s.gcr.io/kube-apiserver v1.20.2 a8c2fdb8bf76 4 months ago 122MB
k8s.gcr.io/kube-scheduler v1.20.2 ed2c44fbdd78 4 months ago 46.4MB
kubernetesui/dashboard v2.1.0 9a07b5b4bfac 5 months ago 226MB
k8s.gcr.io/etcd 3.4.13-0 0369cf4303ff 8 months ago 253MB
k8s.gcr.io/coredns 1.7.0 bfe3a36ebd25 11 months ago 45.2MB
kubernetesui/metrics-scraper v1.0.4 86262685d9ab 13 months ago 36.9MB
k8s.gcr.io/pause
發現沒有我們剛才部署的映象,這裡我們下載一個映象進行重新部署測試
下載映象
docker@minikube:~$ docker pull cilium/echoserver
Using default tag: latest
latest: Pulling from cilium/echoserver
a6014dd53961: Pull complete
fedc7896051b: Pull complete
5500b395a348: Pull complete
880bf53d0210: Pull complete
94791026eeca: Pull complete
d51579691189: Pull complete
7fd34bf14970: Pull complete
4b12f3ef8e65: Pull complete
b0e3c31807a2: Pull complete
e0962580d825: Pull complete
46b541e4c252: Pull complete
Digest: sha256:d6bd1dee4502cc50a974a97563330b4caaa2ac5b00a20ad2b82f4aa0e25e14fe
Status: Downloaded newer image for cilium/echoserver:latest
docker.io/cilium/echoserver:latest
部署新的echoserver
kubectl create deployment testechoserver --image=cilium/echoserver
deployment.apps/testechoserver created
arvin@ubuntu:~$ kubectl expose deployment testechoserver --type=NodePort --port=8080
service/testechoserver exposed
檢視部署狀態
arvin@ubuntu:~$ kubectl get deployment
NAME READY UP-TO-DATE AVAILABLE AGE
hello-minikube 0/1 1 0 26m
testechoserver 1/1 1 1 2m12s
檢視建立的服務
arvin@ubuntu:~$ kubectl get services testechoserver
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
testechoserver NodePort 10.106.69.154 <none> 8080:32617/TCP 2m3s
設定埠轉發
arvin@ubuntu:~$ kubectl port-forward service/testechoserver 7080:8080
Forwarding from 127.0.0.1:7080 -> 8080
Forwarding from [::1]:7080 -> 8080
使用curl 檢視資訊
arvin@ubuntu:~$ curl http://127.0.0.1:7080
Hostname: testechoserver-5668cd9764-jslfz
Pod Information:
-no pod information available-
Server values:
server_version=nginx: 1.13.3 - lua: 10008
Request Information:
client_address=::ffff:127.0.0.1
method=GET
real path=/
query=
request_version=1.1
request_scheme=http
request_uri=http://127.0.0.1:8080/
Request Headers:
accept=*/*
host=127.0.0.1:7080
user-agent=curl/7.68.0
Request Body:
-no body in request-
七、管理叢集
minikube 的一些命令
暫停叢集而不影響部署的應用程式
minikube pause
停止叢集，相對應的是minikube start啟動叢集
minikube stop
設定記憶體大小為2048MB，設定後建立新的叢集會使用改配置
minikube config set memory 2048
檢視擴充套件外掛資訊
minikube addons list
刪除叢集
minikube delete
具體可根據minikube --help 檢視學習