文章目录
参考官网：https://kubernetes.github.io/ingress-nginx/user-guide/nginx-configuration/configmap/
1.ConfigMap配置管理介绍
ConfigMap配置管理
• Configmap用于保存配置数据，以键值对形式存储。
• configMap 资源提供了向 Pod 注入配置数据的方法。
• 旨在让镜像和配置文件解耦，以便实现镜像的可移植性和可复用性。
典型的使用场景
• 填充环境变量的值
• 设置容器内的命令行参数
• 填充卷的配置文件
2.创建ConfigMap的4种方式
创建ConfigMap的方式有4种：
• 使用字面值创建
• 使用文件创建
• 使用目录创建
• 编写configmap的yaml文件创建
2.1 使用字面值创建ConfigMap
kubectl create configmap my-config --from-literal=key1=config1 --from-literal=key2=config2
[kubeadm@server1 ~]$ mkdir cm
[kubeadm@server1 ~]$ ls
calico.yaml cm kube-flannel.yml mainfest nginx.tar
[kubeadm@server1 ~]$ cd cm/
[kubeadm@server1 cm]$ kubectl create configmap my-config --from-literal=key1=config1 --from-literal=key2=config2
configmap/my-config created
[kubeadm@server1 cm]$ kubectl get cm
NAME DATA AGE
my-config 2 10s
[kubeadm@server1 cm]$ kubectl get cm -n kube-system
NAME DATA AGE
coredns 1 8d
extension-apiserver-authentication 6 8d
kube-flannel-cfg 2 21h
kube-proxy 2 8d
kubeadm-config 2 8d
kubelet-config-1.18 1 8d
[kubeadm@server1 cm]$ kubectl describe cm my-config
Name: my-config
Namespace: default
Labels: <none>
Annotations: <none>
Data
====
key1:
----
config1
key2:
----
config2
Events: <none>
2.2 使用文件创建ConfigMap
kubectl create configmap my-config-2 --from-file=/etc/resolv.conf
[kubeadm@server1 cm]$ kubectl create configmap my-config-2 --from-file=/etc/resolv.conf
configmap/my-config-2 created
[kubeadm@server1 cm]$ kubectl get cm
NAME DATA AGE
my-config 2 2m51s
my-config-2 1 3s
[kubeadm@server1 cm]$ kubectl describe cm my-config-2
Name: my-config-2
Namespace: default
Labels: <none>
Annotations: <none>
Data
====
resolv.conf:
----
nameserver 114.114.114.114
Events: <none>
2.3 使用目录创建ConfigMap
kubectl create configmap my-config-3 --from-file=test`
[kubeadm@server1 cm]$ mkdir test
[kubeadm@server1 cm]$ cp /etc/fstab test/
[kubeadm@server1 cm]$ cp /etc/resolv.conf test/
[kubeadm@server1 cm]$ ll test/
total 8
-rw-r--r-- 1 kubeadm kubeadm 502 Jun 27 19:47 fstab
-rw-rw-r-- 1 kubeadm kubeadm 28 Jun 27 19:47 resolv.conf
[kubeadm@server1 cm]$ kubectl create configmap my-config-3 --from-file=test
configmap/my-config-3 created
[kubeadm@server1 cm]$ kubectl get cm
NAME DATA AGE
my-config 2 5m50s
my-config-2 1 3m2s
my-config-3 2 6s
[kubeadm@server1 cm]$ kubectl describe cm my-config-3
Name: my-config-3
Namespace: default
Labels: <none>
Annotations: <none>
Data
====
fstab:
----
#
# /etc/fstab
# Created by anaconda on Thu May 7 08:28:06 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
#
UUID=8d5190d9-d50b-49f4-a64e-7a985e53dc81 / xfs defaults 0 0
UUID=60910b20-bbdc-4701-bba3-a9760086a1a0 /boot xfs defaults 0 0
#UUID=2a714265-f92d-4429-87da-9f09e32e6ff2 swap swap defaults 0 0
resolv.conf:
----
nameserver 114.114.114.114
Events: <none>
2.4 编写configmap的yaml文件创建ConfigMap
[kubeadm@server1 cm]$ vim cm1.yml
[kubeadm@server1 cm]$ cat cm1.yml
apiVersion: v1
kind: ConfigMap
metadata:
name: cm1-config
data:
db_host: "172.25.0.250"
db_port: "3306"
[kubeadm@server1 cm]$ kubectl apply -f cm1.yml
configmap/cm1-config created
[kubeadm@server1 cm]$ kubectl get cm
NAME DATA AGE
cm1-config 2 10s
my-config 2 172m
my-config-2 1 169m
my-config-3 2 166m
[kubeadm@server1 cm]$ kubectl describe cm cm1-config
Name: cm1-config
Namespace: default
Labels: <none>
Annotations:
Data
====
db_host:
----
172.25.0.250
db_port:
----
3306
Events: <none>
3.使用configmap
如何使用configmap：
• 通过环境变量的方式直接传递给pod
• 通过在pod的命令行下运行的方式
• 作为volume的方式挂载到pod内
3.1 使用configmap设置环境变量
示例一：重新定义configmap的key
[kubeadm@server1 cm]$ vim cm1.yml
[kubeadm@server1 cm]$ cat 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: pod1
image: busybox
command: ["/bin/sh", "-c", "env"]
env:
- name: key1
valueFrom:
configMapKeyRef:
name: cm1-config
key: db_host
- name: key2
valueFrom:
configMapKeyRef:
name: cm1-config
key: db_port
restartPolicy: Never
[kubeadm@server1 cm]$ kubectl apply -f cm1.yml
configmap/cm1-config unchanged
pod/pod1 created
[kubeadm@server1 cm]$ kubectl get cm
NAME DATA AGE
cm1-config 2 7m31s
my-config 2 179m
my-config-2 1 176m
my-config-3 2 173m
[kubeadm@server1 cm]$ kubectl describe cm cm1-config
Name: cm1-config
Namespace: default
Labels: <none>
Annotations:
Data
====
db_host:
----
172.25.0.250
db_port:
----
3306
Events: <none>
[kubeadm@server1 cm]$ kubectl logs pod1
KUBERNETES_PORT=tcp://10.96.0.1:443
KUBERNETES_SERVICE_PORT=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
KUBERNETES_PORT_443_TCP_PROTO=tcp
key2=3306
KUBERNETES_SERVICE_PORT_HTTPS=443
KUBERNETES_PORT_443_TCP=tcp://10.96.0.1:443
KUBERNETES_SERVICE_HOST=10.96.0.1
PWD=/
示例二:直接使用configmap
[kubeadm@server1 cm]$ vim cm1.yml
[kubeadm@server1 cm]$ cat 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: pod1
image: busybox
command: ["/bin/sh", "-c", "env"]
envFrom:
- configMapRef:
name: cm1-config
restartPolicy: Never
[kubeadm@server1 cm]$ kubectl delete pod pod1
pod "pod1" deleted
[kubeadm@server1 cm]$ kubectl apply -f cm1.yml
configmap/cm1-config unchanged
pod/pod1 created
[kubeadm@server1 cm]$ kubectl logs pod1
KUBERNETES_PORT=tcp://10.96.0.1:443
KUBERNETES_SERVICE_PORT=443
HOSTNAME=pod1
SHLVL=1
db_port=3306
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
KUBERNETES_PORT_443_TCP_PROTO=tcp
KUBERNETES_SERVICE_PORT_HTTPS=443
KUBERNETES_PORT_443_TCP=tcp://10.96.0.1:443
KUBERNETES_SERVICE_HOST=10.96.0.1
PWD=/
db_host=172.25.0.250
3.2 使用conigmap设置命令行参数
[kubeadm@server1 cm]$ kubectl delete pod pod1
pod "pod1" deleted
[kubeadm@server1 cm]$ cat 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: pod1
image: busybox
command: ["/bin/sh", "-c", "echo $(db_host) $(db_port)"]
envFrom:
- configMapRef:
name: cm1-config
restartPolicy: Never
[kubeadm@server1 cm]$ kubectl apply -f cm1.yml
configmap/cm1-config unchanged
pod/pod1 created
[kubeadm@server1 cm]$ kubectl logs pod1
172.25.0.250 3306
3.3 通过数据卷使用configmap
示例一
[kubeadm@server1 cm]$ kubectl delete pod pod1
pod "pod1" deleted
[kubeadm@server1 cm]$ vim cm1.yml
[kubeadm@server1 cm]$ cat 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: pod1
image: busybox
command: ["/bin/sh", "-c", "cat /config/*"]
volumeMounts:
- name: config-volume
mountPath: /config
volumes:
- name: config-volume
configMap:
name: cm1-config
restartPolicy: Never
[kubeadm@server1 cm]$ kubectl apply -f cm1.yml
configmap/cm1-config unchanged
pod/pod1 created
[kubeadm@server1 cm]$ kubectl logs pod1
172.25.0.2503306
示例二
[kubeadm@server1 cm]$ kubectl delete pod pod1
pod "pod1" deleted
[kubeadm@server1 cm]$ vim cm1.yml
[kubeadm@server1 cm]$ cat 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: pod1
image: nginx
volumeMounts:
- name: config-volume
mountPath: /config
volumes:
- name: config-volume
configMap:
name: cm1-config
[kubeadm@server1 cm]$ kubectl apply -f cm1.yml
configmap/cm1-config unchanged
pod/pod1 created
[kubeadm@server1 cm]$ kubectl exec -it pod1 -- bash
root@pod1:/# cd /config/
root@pod1:/config# ls
db_host db_port
root@pod1:/config# cat db_host
172.25.0.250root@pod1:/config# cat db_port
3306root@pod1:/config# exit
[kubeadm@server1 cm]$ kubectl describe cm cm1-config
Name: cm1-config
Namespace: default
Labels: <none>
Annotations:
Data
====
db_host:
----
172.25.0.250
db_port:
----
3306
Events: <none>
[kubeadm@server1 cm]$ kubectl edit cm cm1-config
configmap/cm1-config edited
[kubeadm@server1 cm]$ kubectl describe cm cm1-config
Name: cm1-config
Namespace: default
Labels: <none>
Annotations:
Data
====
db_host:
----
172.25.0.254
db_port:
----
3306
Events: <none>
Pod数据并不会实时更新，需要等待几秒
3.4 configmap热更新
[kubeadm@server1 cm]$ vim cm1.yml
[kubeadm@server1 cm]$ cat cm1.yml
apiVersion: v1
kind: ConfigMap
metadata:
name: cm1-config
data:
db_host: "172.25.0.250"
db_port: "3306"
---
apiVersion: apps/v1
kind: Deployment
metadata:
name: my-nginx
spec:
replicas: 1
selector:
matchLabels:
app: nginx
template:
metadata:
labels:
app: nginx
spec:
containers:
- name: nginx
image: nginx
ports:
- containerPort: 80
volumeMounts:
- name: config-volume
mountPath: /etc/nginx/conf.d
volumes:
- name: config-volume
configMap:
name: nginx-config
[kubeadm@server1 cm]$ vim server.conf
[kubeadm@server1 cm]$ cat server.conf
server {
listen 8000;
server_name _;
location / {
root /usr/share/nginx/html;
index index.html index.htm;
}
}
[kubeadm@server1 cm]$ kubectl create configmap nginx-config --from-file=server.conf
configmap/nginx-config created
[kubeadm@server1 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>
[kubeadm@server1 cm]$ kubectl apply -f cm1.yml
configmap/cm1-config created
deployment.apps/my-nginx created
[kubeadm@server1 cm]$ kubectl get pod
NAME READY STATUS RESTARTS AGE
my-nginx-7db4c4f989-pl6c8 1/1 Running 0 3s
[kubeadm@server1 cm]$ kubectl get pod -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
my-nginx-7db4c4f989-pl6c8 1/1 Running 0 30s 10.244.1.70 server2 <none> <none>
[kubeadm@server1 cm]$ curl 10.244.1.70
curl: (7) Failed connect to 10.244.1.70:80; Connection refused
[kubeadm@server1 cm]$ curl 10.244.1.70:8000
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
[kubeadm@server1 cm]$ kubectl exec my-nginx-7db4c4f989-pl6c8 -- cat /etc/nginx/conf.d/server.conf
server {
listen 8000;
server_name _;
location / {
root /usr/share/nginx/html;
index index.html index.htm;
}
}
修改端口号
[kubeadm@server1 cm]$ kubectl edit cm nginx-config
configmap/nginx-config edited
[kubeadm@server1 cm]$ kubectl exec my-nginx-7db4c4f989-pl6c8 -- cat /etc/nginx/conf.d/server.conf
server {
listen 8080;
server_name _;
location / {
root /usr/share/nginx/html;
index index.html index.htm;
}
}
[kubeadm@server1 cm]$ kubectl get pod -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
my-nginx-7db4c4f989-pl6c8 1/1 Running 0 6m2s 10.244.1.70 server2 <none> <none>
[kubeadm@server1 cm]$ curl 10.244.1.70:8000
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
可以看出configmap热更新以生效,但访问Pod的8080端口是无效的
手动触发pod滚动更新kubectl patch deployments.apps my-nginx --patch '{"spec": {"template": {"metadata": {"annotations": {"version/config": "20200219"}}}}}'