計算機系統

5G云計算

第三章 LINUX Kubernetes 配置資源管理

一、Secret

Secret 是用來保存密碼、token、密鑰等敏感數據的 k8s 資源，這類數據雖然也可以存放在 Pod 或者鏡像中，但是放在 Secret 中是為了更方便的控制如何使用數據，并減少暴露的風險

1.Secret 四種類型

1）kubernetes.io/service-account-token

由 Kubernetes 自動創建，用來訪問 APIServer 的 Secret，Pod 會默認使用這個 Secret 與 APIServer 通信， 并且會自動掛載到 Pod 的 /run/secrets/kubernetes.io/serviceaccount 目錄中

2）Opaque

base64 編碼格式的 Secret，用來存儲用戶自定義的密碼、密鑰等，默認的 Secret 類型

3）kubernetes.io/dockerconfigjson

用來存儲私有 docker registry 的認證信息

4）kubernetes.io/tls

用來存儲 TLS 證書和私鑰信息

2.Pod 需要先引用才能使用某個 secret，Pod 有 3 種方式來使用 secret

1）作為掛載到一個或多個容器上的卷 中的文件

2）作為容器的環境變量

3）由 kubelet 在為 Pod 拉取鏡像時使用

應用場景：憑據
https://kubernetes.io/docs/concepts/configuration/secret///創建 Secret
1、用kubectl create secret命令創建Secret
echo -n 'zhangsan' > username.txt
echo -n 'abc1234' > password.txtkubectl create secret generic mysecret --from-file=username.txt --from-file=password.txtkubectl get secrets
NAME                                 TYPE                                  DATA   AGE
default-token-sggl5                  kubernetes.io/service-account-token   3      6d21h
mysecret                             Opaque                                2      3s
nfs-client-provisioner-token-xpkn5   kubernetes.io/service-account-token   3      3d2hkubectl describe secret mysecret
Name:         mysecret
Namespace:    default
Labels:       <none>
Annotations:  <none>Type:  OpaqueData
====
username.txt:  8 bytes
password.txt:  7 bytes//get或describe指令都不會展示secret的實際內容，這是出于對數據的保護的考慮2、內容用 base64 編碼，創建Secret
echo -n zhangsan | base64
emhhbmdzYW4K=echo -n abc1234 | base64
YWJjMTIzNAo==kubectl create secret generic mysecret1 --from-literal=myname=lisikubectl get secrets
NAME                                 TYPE                                  DATA   AGE
default-token-sggl5                  kubernetes.io/service-account-token   3      6d21h
mysecret                             Opaque                                2      6m
mysecret1                            Opaque                                1      12s
nfs-client-provisioner-token-xpkn5   kubernetes.io/service-account-token   3      3d2hkubectl get secret mysecret1 -o yaml
apiVersion: v1
data:myname: bGlzaQ==
kind: Secret
metadata:creationTimestamp: "2023-08-17T09:04:08Z"managedFields:- apiVersion: v1fieldsType: FieldsV1fieldsV1:f:data:.: {}f:myname: {}f:type: {}manager: kubectl-createoperation: Updatetime: "2023-08-17T09:04:08Z"name: mysecret1namespace: defaultresourceVersion: "160205"selfLink: /api/v1/namespaces/default/secrets/mysecret1uid: 53c6b51e-4089-456a-8ee7-9aefba21db40
type: Opaque//使用方式 
1、將 Secret 掛載到 Volume 中，以 Volume 的形式掛載到 Pod 的某個目錄下
vim secret-test.yaml
apiVersion: v1
kind: Pod
metadata:name: mypod
spec:containers:- name: nginximage: nginxvolumeMounts:- name: secretsmountPath: "/etc/secrets"readOnly: truevolumes:- name: secretssecret:secretName: mysecretkubectl create -f secret-test.yamlkubectl get pods
NAME                                      READY   STATUS    RESTARTS   AGE
mypod                                     1/1     Running   0          46s
nfs-client-provisioner-55bbbfbb9f-bwrhm   1/1     Running   0          2d1hkubectl exec -it mypod bash
# cd /etc/secrets/
# ls
password.txt  username.txt
# cat username.txt
zhangsan# 2、將 Secret 導出到環境變量中
vim secret-test1.yaml
apiVersion: v1
kind: Pod
metadata:name: mypod1
spec:containers:- name: nginximage: nginxenv:- name: TEST_USERvalueFrom:secretKeyRef:name: mysecretkey: username.txt- name: TEST_PASSWORDvalueFrom:secretKeyRef:name: mysecretkey: password.txtenvFrom:- secretRef:name: mysecret1kubectl apply -f secret-test1.yaml kubectl get pods
NAME         READY   STATUS    RESTARTS   AGE
NAME                                      READY   STATUS    RESTARTS   AGE
mypod                                     1/1     Running   0          3m9s
mypod1                                    1/1     Running   0          30s
nfs-client-provisioner-55bbbfbb9f-bwrhm   1/1     Running   0          2d1hkubectl exec -it mypod1 bash
# echo $TEST_USER
zhangsan
# echo $TEST_PASSWORD
abc1234

二.ConfigMap

與Secret類似，區別在于ConfigMap保存的是不需要加密配置的信息
ConfigMap 功能在 Kubernetes1.2 版本中引入，許多應用程序會從配置文件、命令行參數或環境變量中讀取配置信息。ConfigMap API 給我們提供了向容器中注入配置信息的機制，ConfigMap 可以被用來保存單個屬性，也可以用來保存整個配置文件或者JSON二進制大對象

應用場景：應用配置//創建 ConfigMap
1、使用目錄創建
mkdir /opt/configmap/vim /opt/configmap/game.config
enemy.types=aliens,monsters
player.maximum-lives=5 vim /opt/configmap/ui.config
color.good=purple
color.bad=yellow
allow.textmode=truels /opt/configmap/
game.config
ui.configkubectl create configmap game-config --from-file=/opt/configmap/
//--from-file 指定在目錄下的所有文件都會被用在 Con?gMap 里面創建一個鍵值對，鍵的名字就是文件名，值就是文件的內容kubectl get cm
NAME               DATA   AGE
game-config        2      3s
kube-root-ca.crt   1      6d21hkubectl get cm game-config -o yaml
apiVersion: v1
data:game.config: "enemy.types=aliens,monsters\nplayer.maximum-lives=5 \n"ui.config: |color.good=purplecolor.bad=yellowallow.textmode=true
kind: ConfigMap
metadata:creationTimestamp: "2023-08-17T09:13:28Z"managedFields:- apiVersion: v1fieldsType: FieldsV1fieldsV1:f:data:.: {}f:game.config: {}f:ui.config: {}manager: kubectl-createoperation: Updatetime: "2023-08-17T09:13:28Z"name: game-confignamespace: defaultresourceVersion: "161245"selfLink: /api/v1/namespaces/default/configmaps/game-configuid: b198ecb4-2d62-4d5e-bbd8-3fe609986ec42、使用文件創建 
只要指定為一個文件就可以從單個文件中創建 Con?gMap
--from-file 這個參數可以使用多次，即可以使用兩次分別指定上個實例中的那兩個配置文件，效果就跟指定整個目錄是一樣的kubectl create configmap game-config-2 --from-file=/opt/configmap/game.config --from-file=/opt/configmap/ui.configkubectl get configmaps game-config-2 -o yamlkubectl describe cm game-config-23、使用字面值創建 
使用文字值創建，利用 --from-literal 參數傳遞配置信息，該參數可以使用多次，格式如下
kubectl create configmap special-config --from-literal=special.how=very --from-literal=special.type=goodkubectl get configmaps special-config -o yaml
apiVersion: v1
data:special.how: veryspecial.type: good
kind: ConfigMap
metadata:creationTimestamp: "2023-08-17T09:16:42Z"managedFields:- apiVersion: v1fieldsType: FieldsV1fieldsV1:f:data:.: {}f:special.how: {}f:special.type: {}manager: kubectl-createoperation: Updatetime: "2023-08-17T09:16:42Z"name: special-confignamespace: defaultresourceVersion: "161613"selfLink: /api/v1/namespaces/default/configmaps/special-configuid: be38184f-ac39-4e38-92df-87e01a2b7a60kubectl delete cm --all
kubectl delete pod --all//Pod 中使用 ConfigMap 
1、使用 ConfigMap 來替代環境變量
vim env.yaml
apiVersion: v1
kind: ConfigMap
metadata:name: special-confignamespace: default
data:special.how: veryspecial.type: good
---
apiVersion: v1
kind: ConfigMap
metadata:name: env-confignamespace: default
data:log_level: INFOkubectl apply -f env.yaml kubectl get cm
NAME               DATA   AGE
env-config         1      3s
kube-root-ca.crt   1      57s
special-config     2      3s//Pod的創建
vim test-pod.yaml
apiVersion: v1
kind: Pod
metadata:name: test-pod
spec:containers:- name: busyboximage: busybox:1.28.4command: [ "/bin/sh", "-c", "env" ]env:- name: SPECIAL_HOW_KEYvalueFrom:configMapKeyRef:name: special-configkey: special.how- name: SPECIAL_TYPE_KEYvalueFrom:configMapKeyRef:name: special-configkey: special.typeenvFrom:- configMapRef:name: env-configrestartPolicy: Neverkubectl apply -f test-pod.yamlkubectl get pods
NAME                                      READY   STATUS      RESTARTS   AGE
nfs-client-provisioner-55bbbfbb9f-s2fcr   1/1     Running     0          2m8s
test-pod                                  0/1     Completed   0          20skubectl logs test-pod
KUBERNETES_SERVICE_PORT=443
KUBERNETES_PORT=tcp://10.0.0.1:443
HOSTNAME=test-pod
SHLVL=1
SPECIAL_HOW_KEY=very            #賦值變量 SPECIAL_HOW_KEY 的值為 special-config 的 special.how: very
HOME=/root
SPECIAL_TYPE_KEY=good
KUBERNETES_PORT_443_TCP_ADDR=10.0.0.1
PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
KUBERNETES_PORT_443_TCP_PORT=443
KUBERNETES_PORT_443_TCP_PROTO=tcp
log_level=INFO                  #引入 env-config 的變量 log_level: INFO
KUBERNETES_SERVICE_PORT_HTTPS=443
KUBERNETES_PORT_443_TCP=tcp://10.0.0.1:443
KUBERNETES_SERVICE_HOST=10.0.0.1
PWD=/2、用 ConfigMap 設置命令行參數 
vim test-pod2.yaml
apiVersion: v1
kind: Pod
metadata:name: test-pod2
spec:containers:- name: busyboximage: busybox:1.28.4command: - /bin/sh- -c- echo "$(SPECIAL_HOW_KEY) $(SPECIAL_TYPE_KEY)"env:- name: SPECIAL_HOW_KEYvalueFrom:configMapKeyRef:name: special-configkey: special.how- name: SPECIAL_TYPE_KEYvalueFrom:configMapKeyRef:name: special-configkey: special.typeenvFrom:- configMapRef:name: env-configrestartPolicy: Neverkubectl apply -f test-pod2.yamlkubectl get pods
NAME                                      READY   STATUS      RESTARTS   AGE
nfs-client-provisioner-55bbbfbb9f-s2fcr   1/1     Running     0          4m10s
test-pod                                  0/1     Completed   0          2m22s
test-pod2                                 0/1     Completed   0          7skubectl logs test-pod2
very good3、通過數據卷插件使用Con?gMap 
在數據卷里面使用 Con?gMap，就是將文件填入數據卷，在這個文件中，鍵就是文件名，鍵值就是文件內容
vim test-pod3.yaml
apiVersion: v1
kind: Pod
metadata:name: test-pod3
spec:containers:- name: busyboximage: busybox:1.28.4command: [ "/bin/sh", "-c", "sleep 36000" ]volumeMounts:- name: config-volumemountPath: /etc/configvolumes:- name: config-volumeconfigMap:name: special-configrestartPolicy: Neverkubectl apply -f test-pod3.yaml kubectl get pods
NAME                                      READY   STATUS      RESTARTS   AGE
nfs-client-provisioner-55bbbfbb9f-s2fcr   1/1     Running     0          5m20s
test-pod                                  0/1     Completed   0          3m32s
test-pod2                                 0/1     Completed   0          77s
test-pod3                                 1/1     Running     0          6skubectl exec -it test-pod3 sh# cd /etc/config/# ls
special.how   special.type# vi special.how # vi special.type RESTARTS   AGE
nfs-client-provisioner-55bbbfbb9f-s2fcr   1/1     Running     0          5m20s
test-pod                                  0/1     Completed   0          3m32s
test-pod2                                 0/1     Completed   0          77s
test-pod3                                 1/1     Running     0          6skubectl exec -it test-pod3 sh# cd /etc/config/# ls
special.how   special.type# vi special.how # vi special.type