簡(jiǎn)介

生產(chǎn)環(huán)境中很多應(yīng)用程序的配置可能需要通過(guò)配置文件，命令行參數(shù)和環(huán)境變量的組合配置來(lái)完成。這些配置應(yīng)該從image中解耦，以此來(lái)保持容器化應(yīng)用程序的可移植性。在K8S1.2后引入ConfigMap來(lái)處理這種類型的配置數(shù)據(jù)。

• Configmap用于保存服務(wù)的配置數(shù)據(jù),以鍵值對(duì)形式存儲(chǔ)。
• configMap 資源提供了向 Pod 注入配置數(shù)據(jù)的方法。
• 旨在讓鏡像和配置文件解耦,以便實(shí)現(xiàn)鏡像的可移植性和可復(fù)用性。
• 典型的使用場(chǎng)景:
  • 填充環(huán)境變量的值
  • 設(shè)置容器內(nèi)的命令行參數(shù)
  • 填充卷的配置文件

創(chuàng)建ConfigMap

創(chuàng)建ConfigMap的方式有4種:
? 使用字面值創(chuàng)建
? 使用文件創(chuàng)建
? 使用目錄創(chuàng)建
? 編寫configmap的yaml文件創(chuàng)建

使用字面值創(chuàng)建

[root@server2 manifest]# kubectl create configmap mycm --from-literal=wo=caoaoyuan --from-literal=ni=liuyan configmap/mycm created /cm名，任意 /輸入健值對(duì) [root@server2 manifest]# kubectl get cm NAME DATA AGE mycm 2 115s [root@server2 manifest]# kubectl describe cm mycm Name: mycm Namespace: default Labels: <none> Annotations: <none>Data ==== ni: ---- liuyan wo: ---- caoaoyuan Events: <none>

文件的形式

[root@server2 manifest]# kubectl create configmap my-config-2 --from-file=/etc/resolv.conf configmap/my-config-2 created [root@server2 manifest]# kubectl get cm NAME DATA AGE my-config-2 1 7s mycm 2 4m4s[root@server2 manifest]# kubectl describe cm my-config-2 Name: my-config-2 Namespace: default Labels: <none> Annotations: <none>Data ==== resolv.conf: //key的名稱是文件名稱 ---- 3 nameserver 114.114.114.114 //value的值是這個(gè)文件的內(nèi)容Events: <none>[root@server2 manifest]# cat /etc/resolv.confnameserver 114.114.114.114

通過(guò)目錄創(chuàng)建

[root@server2 ~]# mkdir test [root@server2 ~]# cp /etc/resolv.conf test/ [root@server2 ~]# cp /etc/fstab test/ [root@server2 ~]# ls test/ fstab resolv.conf[root@server2 ~]# kubectl create configmap my-config-3 --from-file=test configmap/my-config-3 created [root@server2 ~]# kubectl describe cm my-config-3 Name: my-config-3 Namespace: default Labels: <none> Annotations: <none>Data ==== fstab: ----# # /etc/fstab # Created by anaconda on Tue Apr 28 02:35:30 2020 # # Accessible filesystems, by reference, are maintained under '/dev/disk' # See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info # /dev/mapper/rhel-root / xfs defaults 0 0 UUID=004d1dd6-221a-4763-a5eb-c75e18655041 /boot xfs defaults 0 0 #/dev/mapper/rhel-swap swap swap defaults 0 0resolv.conf: ----nameserver 114.114.114.114Events: <none>

可以發(fā)現(xiàn)通過(guò)目錄進(jìn)行創(chuàng)建的時(shí)候，是把目錄內(nèi)的文件作為，key， 其內(nèi)容作為 value。

編寫configmap的yaml文件

[root@server2 ~]# mkdir cm [root@server2 ~]# cd cm/ [root@server2 cm]# vim cm1.yml apiVersion: v1 kind: ConfigMap metadata:name: cm1-config data:db_host: "172.25.0.250" //還是健值對(duì)的形式db_port: "3306"[root@server2 cm]# kubectl create -f cm1.yaml [root@server2 cm]# kubectl describe cm cm1 Name: cm1-config Namespace: default Labels: <none> Annotations: Data ==== db_host: ---- 172.25.0.250 db_port: ---- 3306 Events: <none>

如何使用configmap

通過(guò)環(huán)境變量的方式直接傳遞給pod

通過(guò)在pod的命令行下運(yùn)行的方式

作為volume的方式掛載到pod內(nèi)

通過(guò)環(huán)境變量

方式一:重新定義

[root@server2 cm]# vim cm1.yml apiVersion: v1 kind: ConfigMap metadata:name: cm1-config data:db_host: "172.25.0.250"db_port: "3306"--- apiVersion: v1 kind: Pod metadata:name: pod1 spec:containers:- name: pod1image: busyboxcommand: ["/bin/sh", "-c", "env"] //啟用這個(gè)pod執(zhí)行這個(gè)命令env:- name: key1 //環(huán)境變量名稱valueFrom: //數(shù)據(jù)來(lái)源configMapKeyRef:name: cm1-config //把configmap的數(shù)據(jù)應(yīng)用到pod中key: db_host //健是上面定義的key1，值是db_host的值- name: key2valueFrom:configMapKeyRef:name: cm1-configkey: db_portrestartPolicy: Never [root@server2 cm]# kubectl apply -f cm1.yml configmap/cm1-config unchanged pod/pod1 created [root@server2 cm]# kubectl get pod NAME READY STATUS RESTARTS AGE pod1 0/1 Completed 0 6s //執(zhí)行命令后就完成了 [root@server2 cm]# kubectl logs pod1 KUBERNETES_SERVICE_PORT=443 KUBERNETES_PORT=tcp://10.96.0.1:443 HOSTNAME=pod1 SHLVL=1 HOME=/root KUBERNETES_PORT_443_TCP_ADDR=10.96.0.1 PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin KUBERNETES_PORT_443_TCP_PORT=443 key1=172.25.0.250 //key1對(duì)應(yīng)db_host值 KUBERNETES_PORT_443_TCP_PROTO=tcp key2=3306 //key2對(duì)應(yīng)db_port的值 KUBERNETES_SERVICE_PORT_HTTPS=443 KUBERNETES_PORT_443_TCP=tcp://10.96.0.1:443 KUBERNETES_SERVICE_HOST=10.96.0.1 PWD=/ [root@se

方式二:直接導(dǎo)入cm

[root@server2 cm]# vim cm1.yml apiVersion: v1 kind: ConfigMap metadata:name: cm1-config data:db_host: "172.25.0.250"db_port: "3306"--- apiVersion: v1 kind: Pod metadata:name: pod1 spec:containers:- name: pod1image: busyboxcommand: ["/bin/sh", "-c", "env"]envFrom:- configMapRef:name: cm1-config ///直接從cm中導(dǎo)入數(shù)據(jù)restartPolicy: Never [root@server2 cm]# kubectl apply -f cm1.yml configmap/cm1-config unchanged pod/pod1 created [root@server2 cm]# kubectl get pod NAME READY STATUS RESTARTS AGE pod1 0/1 Completed 0 6s [root@server2 cm]# kubectl logs pod1 KUBERNETES_SERVICE_PORT=443 KUBERNETES_PORT=tcp://10.96.0.1:443 HOSTNAME=pod1 SHLVL=1 db_port=3306 ... db_host=172.25.0.250 //導(dǎo)入了cm中的值

使用conigmap設(shè)置命令行參數(shù)

[root@server2 cm]# vim cm1.yml apiVersion: v1 kind: ConfigMap metadata:name: cm1-config data:db_host: "172.25.0.250"db_port: "3306"--- apiVersion: v1 kind: Pod metadata:name: pod1 spec:containers:- name: pod1image: busyboxcommand: ["/bin/sh", "-c", "echo $(db_host) $(db_port)"] //命令行中直接調(diào)用變量envFrom:- configMapRef:name: cm1-configrestartPolicy: Never[root@server2 cm]# kubectl apply -f cm1.yml configmap/cm1-config unchanged pod/pod1 created [root@server2 cm]# kubectl logs pod1 172.25.0.250 3306 //調(diào)用出來(lái)了

通過(guò)數(shù)據(jù)卷使用configmap

[root@server2 cm]# vim cm1.yml apiVersion: v1 kind: ConfigMap metadata:name: cm1-config data:db_host: "172.25.0.250"db_port: "3306"--- apiVersion: v1 kind: Pod metadata:name: pod1 spec:containers:- name: pod1image: busybox command: ["/bin/sh", "-c", "cat /config/db_host"] /查看改目錄下內(nèi)容，沒(méi)有會(huì)自動(dòng)創(chuàng)建volumeMounts: /卷掛載- name: config-volume /使用的卷的名稱mountPath: /config /掛載點(diǎn)volumes: /指定卷- name: config-volume //指定卷名稱configMap:name: cm1-config //映射到cm上， [root@server2 cm]# kubectl apply -f cm1.yml configmap/cm1-config unchanged pod/pod1 created [root@server2 cm]# kubectl logs pod1 172.25.0.250 db_host的值

更改一下：

command: ["/bin/sh", "-c", "cat /config/db_port"] /改為查看端口[root@server2 cm]# kubectl apply -f cm1.yml configmap/cm1-config unchanged pod/pod1 created [root@server2 cm]# kubectl logs pod1 3306

這樣就明白了吧。
我們還可以登陸進(jìn)去看一下。

[root@server2 cm]# cat cm1.yml ...(省略) spec:containers:- name: pod1image: nginx /換為nginx鏡像volumeMounts:- name: config-volumemountPath: /configvolumes:- name: config-volumeconfigMap:name: cm1-config [root@server2 cm]# kubectl apply -f cm1.yml configmap/cm1-config unchanged pod/pod1 created [root@server2 cm]# kubectl exec -it pod1 -- bash root@pod1:/# cd /config/ root@pod1:/config# ls db_host db_portroot@pod1:/config# cat db_host 172.25.0.250 root@pod1:/config# cat db_port 3306root@pod1:/config#

configmap熱更新

configmap管理的是配置數(shù)據(jù)，是和服務(wù)掛鉤的，當(dāng)服務(wù)配置發(fā)生改變時(shí)，cm 也應(yīng)該進(jìn)行熱更新。

就比如我們上面的 cm 中有兩個(gè)數(shù)據(jù)， db_host 、db_port，當(dāng)他們的數(shù)據(jù)發(fā)生改變時(shí)，會(huì)不會(huì)進(jìn)行熱更新哪。

[root@server2 cm]# kubectl edit cm cm1-config //直接編輯這個(gè) cm # Please edit the object below. Lines beginning with a '#' will be ignored, # and an empty file will abort the edit. If an error occurs while saving this file will be # reopened with the relevant failures. # apiVersion: v1 data:db_host: 172.25.0.100db_port: "3300" //改變地址和端口 kind: ConfigMap[root@server2 cm]# kubectl describe cm cm1-config Name: cm1-config Namespace: default Labels: <none> Annotations: Data ==== db_host: ---- 172.25.0.100 db_port: ---- 3300 //可見(jiàn)cm已經(jīng)改變 Events: <none>

那末pod中會(huì)不會(huì)自動(dòng)進(jìn)行更新哪？

[root@server2 cm]# kubectl exec -it pod1 -- cat /config/db_host 172.25.0.100 [root@server2 cm]# kubectl exec -it pod1 -- cat /config/db_port 3300

我們?cè)偻獠扛峦昃碇?#xff0c;pod內(nèi)也發(fā)生了變化。但是pod的服務(wù)并沒(méi)有發(fā)生變化。
我們現(xiàn)在把 pod 內(nèi) nginx 的配置文件放到數(shù)據(jù)卷中，將 cm 和pod內(nèi)的容器結(jié)合起來(lái)，當(dāng)我們更改時(shí)，讓他自動(dòng)熱更新到 pod 中 的 nginx 服務(wù) 中去。

這是我們就需要用到deployment的控制器來(lái)進(jìn)行滾動(dòng)更新。

[root@server2 cm]# vim server.conf //編寫一個(gè)nginx的配置文件 server {listen 8000; / 修改一下端口server_name _;location / {root /usr/share/nginx/html;index index.html index.htm;} }[root@server2 cm]# kubectl create configmap nginx-config --from-file=server.conf //創(chuàng)建cm configmap/nginx-config created [root@server2 cm]# kubectl describe cm nginx-config Name: nginx-config Namespace: default Labels: <none> Annotations: <none>Data ==== server.conf: ---- server {listen 8000;server_name _;location / {root /usr/share/nginx/html;index index.html index.htm;} }Events: <none>

創(chuàng)建控制器：

apiVersion: apps/v1 kind: Deployment metadata:name: my-nginx spec:replicas: 1selector:matchLabels:app: nginxtemplate:metadata:labels:app: nginxspec:containers:- name: nginximage: nginxvolumeMounts:- name: config-volumemountPath: /etc/nginx/conf.d //掛載到include目錄下volumes:- name: config-volumeconfigMap:name: nginx-config //映射nginx-config 這個(gè)cm的數(shù)據(jù) [root@server2 cm]# kubectl apply -f cm1.yml deployment.apps/my-nginx created [root@server2 cm]# kubectl get pod -o wide NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES my-nginx-575fd5b9c4-nmm4b 1/1 Running 0 34s 10.244.141.216 server3 <none> <none> [root@server2 cm]# curl 10.244.141.216 curl: (7) Failed connect to 10.244.141.216:80; Connection refused [root@server2 cm]# curl 10.244.141.216:8000 <!DOCTYPE html> <html> <head> <title>Welcome to nginx!</title> //80端口訪問(wèn)不到，8000端口生效了

登陸進(jìn)pod中查看：

[root@server2 cm]# kubectl exec -it my-nginx-7db4c4f989-scdc4 -- cat /etc/nginx/conf.d/server.conf server {listen 8000; /是8000端口server_name _;location / {root /usr/share/nginx/html;index index.html index.htm;} }

熱更新：

[root@server2 cm]# kubectl edit cm nginx-config //編輯cm data:server.conf: "server {\n listen\t8080 端口換為8080端口[root@server2 cm]# kubectl exec my-nginx-7db4c4f989-scdc4 -- cat /etc/nginx/conf.d/server.conf server {listen 8080; /變成了8080端口server_name _;location / {root /usr/share/nginx/html;index index.html index.htm;} }

但是pod仍然沒(méi)有改變，只是配置文件變了，還沒(méi)有觸發(fā)。

[root@server2 cm]# curl 10.244.22.11:8080 curl: (7) Failed connect to 10.244.22.11:8080; Connection refused [root@server2 cm]# curl 10.244.22.11:8000 <!DOCTYPE html> <html> <head> <title>Welcome to nginx!</title> 8000端口依然訪問(wèn)，更新后的8080端口訪問(wèn)不到

需要手動(dòng)觸發(fā)Pod滾動(dòng)更新, 這樣才能再次加載nginx.conf配置文件:

[root@server2 cm]# kubectl patch deployments.apps my-nginx --patch \ '{"spec": {"template":{"metadata": {"annotations": {"version/config": "2020062701"}}}}}'

my-nginx 指定控制器，因?yàn)榭刂破飨驴赡苡卸鄠€(gè)pod
version/config": "20200219指定版本

這是之前的pod： [root@server2 cm]# kubectl get pod -o wide NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES my-nginx-7db4c4f989-scdc4 1/1 Running 0 16m 10.244.22.11 server4 <none> <none> [root@server2 cm]# kubectl patch deployments.apps my-nginx --patch '{"spec": {"template":{"metadata": {"annotations": {"version/config": "2020062701"}}}}}' deployment.apps/my-nginx patched [root@server2 cm]# kubectl get pod -o wide NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES my-nginx-7db4c4f989-scdc4 1/1 Running 0 20m 10.244.22.11 server4 <none> <none> my-nginx-7f45d597d5-n7jft 0/1 ContainerCreating 0 4s <none> server3 <none> <none> [root@server2 cm]# kubectl get pod -o wide NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES my-nginx-7db4c4f989-scdc4 0/1 Terminating 0 20m <none> server4 <none> <none> my-nginx-7f45d597d5-n7jft 1/1 Running 0 7s 10.244.141.217 server3 <none> <none>

可以看出新建了一個(gè)pod，之前的pod已經(jīng)刪除了

[root@server2 cm]# curl 10.244.141.217:8080 <!DOCTYPE html> <html> <head> <title>Welcome to nginx!</title> /已經(jīng)切換到8080端口了

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