K8S ConfigMap介紹:
一、ConfigMap的作用
configmap和secret是兩種特殊的存儲卷,它們不是給pod提供存儲空間用的,而是給管理員或者用戶提供了從外部向pod內部注入信息的方式.
configmap:把配置文件放在配置中心上,然后多個pod讀取配置中心的配置文件,不過,configmap中的配置信息都是明文的,所以不安全;
secret:功能和configmap一樣,只不過配置中心存儲的配置文件不是明文的.configmap和secret也是專屬於某個名稱空間的.
1.Configmap用於保存配置數據，以鍵值對形式存儲。
2.configMap 資源提供了向 Pod 注入配置數據的方法。
3.旨在讓鏡像和配置文件解耦，以便實現鏡像的可移植性和可復用性。
二、創建ConfigMap的方式有4種:
1.通過key-value字符串創建
2.使用文件創建
3.使用目錄創建
4.編寫configmap的yaml文件創建
2.1、通過key-value字符串的方式創建
#創建configmap其中cm1是名字，key1是鍵，config1是值 [root@k8s-master ~]# kubectl create configmap cm1 --from-literal=key1=config1 --from-literal=key2=config2 configmap/cm1 created [root@k8s-master ~]# kubectl get cm NAME DATA AGE cm1 2 5s [root@k8s-master ~]# [root@k8s-master ~]# kubectl get cm cm1 NAME DATA AGE cm1 2 13s [root@k8s-master ~]# kubectl describe cm cm1 Name: cm1 Namespace: default Labels: <none> Annotations: <none> Data ==== key1: ---- config1 key2: ---- config2 Events: <none> [root@k8s-master ~]# #cm1配置以yaml文件方式輸出 [root@k8s-master ~]# kubectl get cm cm1 -o yaml apiVersion: v1 data: key1: config1 key2: config2 kind: ConfigMap metadata: creationTimestamp: "2021-01-02T09:26:34Z" name: cm1 namespace: default resourceVersion: "160052" selfLink: /api/v1/namespaces/default/configmaps/cm1 uid: 0ad32521-f0c5-4490-a0e9-34bb0ff59f9c [root@k8s-master ~]#
2.2、文件創建是通過--from-file參數來設定,key的名稱是文件名稱，value的值是文件的內容.
[root@k8s-master ~]# kubectl create configmap cm2 --from-file=/etc/resolv.conf configmap/cm2 created [root@k8s-master ~]# kubectl get cm cm2 NAME DATA AGE cm2 1 6s [root@k8s-master ~]# kubectl describe cm cm2 Name: cm2 Namespace: default Labels: <none> Annotations: <none> Data ==== resolv.conf: ---- # Generated by NetworkManager nameserver 192.168.10.2 Events: <none> [root@k8s-master ~]# 其中，--from-file可以使用多次，比如： # kubectl create configmap cm2 --from-file=file1 --from-file=file2
2.3、使用目錄創建configmap,也是通過--from-file參數來設定。
# 目錄中的文件名為key，文件內容是value # kubectl create configmap cm3 --from-file=/path
2.4、通過編寫configmap的yaml/json文件創建（推薦）
[root@k8s-master ~]# cat cm4.yaml apiVersion: v1 kind: ConfigMap metadata: name: cm4 data: host_name: "k8s-master" host_port: "22" host_ip: "192.168.10.10" [root@k8s-master ~]# [root@k8s-master ~]# kubectl apply -f cm4.yaml configmap/cm4 created [root@k8s-master ~]# kubectl get cm cm4 NAME DATA AGE cm4 3 12s [root@k8s-master ~]# [root@k8s-master ~]# kubectl get cm cm4 -o yaml apiVersion: v1 data: host_ip: 192.168.10.10 host_name: k8s-master host_port: "22" kind: ConfigMap metadata: annotations: kubectl.kubernetes.io/last-applied-configuration: | {"apiVersion":"v1","data":{"host_ip":"192.168.10.10","host_name":"k8s-master","host_port":"22"},"kind":"ConfigMap","metadata":{"annotations":{},"name":"cm4","namespace":"default"}} creationTimestamp: "2021-01-02T09:54:22Z" name: cm4 namespace: default resourceVersion: "162402" selfLink: /api/v1/namespaces/default/configmaps/cm4 uid: 85e48e8a-e3fb-4821-ade8-658882709277 [root@k8s-master ~]#
2.5 編寫cm文件的推薦方式：
# cat mongo-configmap.yaml apiVersion: v1 kind: ConfigMap metadata: name: mongo-config labels: app: mongo-config data: mongod.conf: | storage: dbPath: /data/db journal: enabled: true systemLog: destination: file logAppend: true path: /var/log/mongodb/mongod.log net: port: 27017 bindIp: 0.0.0.0 processManagement: timeZoneInfo: /usr/share/zoneinfo
三、如何使用configmap
1.通過環境變量的方式直接傳遞給pod
2.通過在pod的命令行下運行的方式
3.作為volume的方式掛載到pod內
3.1 使用configmap設置環境變量
方式1：通過引用cm4中的變量方式，供pod使用.
# configMap 定義的cm4文件 [root@k8s-master ~]# cat cm4.yaml apiVersion: v1 kind: ConfigMap metadata: name: cm4 data: host_name: "k8s-master" host_port: "22" host_ip: "192.168.10.10" #pod引用cm4中的變量 [root@k8s-master ~]# cat pod.yaml apiVersion: v1 kind: Pod metadata: name: cm-pod spec: containers: - name: busy-pod image: busybox command: ["/bin/sh","-c","env"] env: - name: key1 #定義的key值 valueFrom: configMapKeyRef: name: cm4 #configmap文件名稱 key: host_ip #value的值 - name: key2 valueFrom: configMapKeyRef: name: cm4 key: host_name - name: key3 valueFrom: configMapKeyRef: name: cm4 key: host_port restartPolicy: Never [root@k8s-master ~]# [root@k8s-master ~]# kubectl apply -f pod.yaml pod/cm-pod created [root@k8s-master ~]# kubectl get pod cm-pod NAME READY STATUS RESTARTS AGE cm-pod 0/1 Completed 0 98s [root@k8s-master ~]# kubectl logs cm-pod KUBERNETES_SERVICE_PORT=443 KUBERNETES_PORT=tcp://10.1.0.1:443 HOSTNAME=cm-pod SHLVL=1 key1=192.168.10.10 key2=k8s-master key3=22 ...只列出部分變量 [root@k8s-master ~]#
方式2：直接導入cm4中的變量
[root@k8s-master ~]# cat pod.yaml apiVersion: v1 kind: Pod metadata: name: cm4-pod spec: containers: - name: busy-pod image: busybox command: ["/bin/sh","-c","env"] envFrom: - configMapRef: name: cm4 restartPolicy: Never [root@k8s-master ~]# [root@k8s-master ~]# kubectl apply -f pod.yaml pod/cm4-pod created [root@k8s-master ~]# kubectl get pod cm4-pod NAME READY STATUS RESTARTS AGE cm4-pod 0/1 Completed 0 27s [root@k8s-master ~]# kubectl logs cm4-pod KUBERNETES_SERVICE_PORT=443 KUBERNETES_PORT=tcp://10.1.0.1:443 HOSTNAME=cm4-pod host_ip=192.168.10.10 host_port=22 HOME=/root host_name=k8s-master ... KUBERNETES_SERVICE_HOST=10.1.0.1 [root@k8s-master ~]#
3.2 使用configmap設置命令行參數,通過在pod的命令行下運行的方式.
[root@k8s-master ~]# cat pod.yaml apiVersion: v1 kind: Pod metadata: name: test-pod spec: containers: - name: pod1 image: busybox command: ["/bin/sh","-c","echo $(host_ip) $(host_port) $(host_name)"] //命令行參數 envFrom: - configMapRef: name: cm4 restartPolicy: Never [root@k8s-master ~]# [root@k8s-master ~]# kubectl apply -f pod.yaml pod/test-pod created [root@k8s-master ~]# kubectl get pod NAME READY STATUS RESTARTS AGE test-pod 0/1 Completed 0 3s [root@k8s-master ~]# kubectl logs test-pod 192.168.10.10 22 k8s-master [root@k8s-master ~]#
3.3 將數據卷cm4以volume的方式掛載到pod內.
# configMap中定義的cm4文件 [root@k8s-master ~]# cat cm4.yaml apiVersion: v1 kind: ConfigMap metadata: name: cm4 data: host_name: "k8s-master" host_port: "22" host_ip: "192.168.10.10" [root@k8s-master ~]# #pod掛載cm4文件 [root@k8s-master ~]# cat pod.yaml apiVersion: v1 kind: Pod metadata: name: v-pod spec: containers: - name: pod1 image: busybox:latest command: - sleep - "3600" imagePullPolicy: IfNotPresent volumeMounts: - name: config-volume mountPath: /config #掛載到容器的這個目錄中 volumes: - name: config-volume #定義的卷名，和volumeMounts中的name要一直. configMap: name: cm4 #掛載的configMap文件名稱 restartPolicy: Never [root@k8s-master ~]# [root@k8s-master ~]# kubectl apply -f pod.yaml pod/v-pod created [root@k8s-master ~]# kubectl get pod v-pod NAME READY STATUS RESTARTS AGE v-pod 1/1 Running 0 6s [root@k8s-master ~]# kubectl exec -it v-pod -- sh / # cd /config/ /config # ls -ltr total 0 lrwxrwxrwx 1 root root 16 Jan 4 14:07 host_port -> ..data/host_port lrwxrwxrwx 1 root root 16 Jan 4 14:07 host_name -> ..data/host_name lrwxrwxrwx 1 root root 14 Jan 4 14:07 host_ip -> ..data/host_ip /config # cat host_port 22 /config # cat host_ip 192.168.10.10 /config # # cm4里面的key是掛載在pod 的/config目錄下的文件名 文件內容value值 如：host_ip: "192.168.10.10"