Take you through K8S-ConfigMap and persistent storage

preface

K8s can be stored in many ways. This article focuses on ConfigMap and persistent storage – NFS. This is also the common storage method for K8S. It’s hard to explain, so I’ll use Nginx as an example, because Nginx needs both. So let me just draw a little picture here.

This series uses three servers, one of which is networked and two of which is not. The K8S cluster cannot be connected to the network.

Nginx storage type analysis

When using nginx, there are two main directories of concern:

The/etc/nginx/conf. D. and/usr/share/nginx/HTML

One is the configuration file directory and the other is the static resource directory. In production, ConfigMap is used to store configuration files, and NFS is used to store static resources persistently.

The configuration file

├ ─ ─ the/etc/nginx/conf. D ├ ─ ─ the default. The conf ├ ─ ─ a.c onf ├ ─ ─ biggest onf └ ─ ─ Arthur c. onfCopy the code

Static resource

├ ─ ─ the/usr/share/nginx/HTML ├ ─ ─ index. The HTML ├ ─ ─ a.h HTML ├ ─ ─ b.h HTML └ ─ ─ c. HTMLCopy the code

ConfigMap

Creating a working directory

mkdir -p /mldong/k8s/nginx
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Go to the working directory

cd /mldong/k8s/nginx
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Use YAML to define the mode

Define a single

cat <<EOF > /mldong/k8s/nginx/nginx-cm.yaml
apiVersion: v1
kind: ConfigMap
metadata:
  name: nginx-cm
  namespace: mldong-test
data:
  a.conf: |-
    server {
      listen       80;
      server_name  a.mldong.com;
      location / {
        root   /usr/share/nginx/html;
        index  index.html index.htm;
      }
      error_page   500 502 503 504  /50x.html;
      location = /50x.html {
        root   /usr/share/nginx/html;
      }
    }
EOF

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Define multiple

cat <<EOF > /mldong/k8s/nginx/nginx-cm.yaml
apiVersion: v1
kind: ConfigMap
metadata:
  name: nginx-cm
  namespace: mldong-test
data:
  a.conf: |-
    server {
      listen       80;
      server_name  a.mldong.com;
      location / {
        root   /usr/share/nginx/html/a;
        index  index.html index.htm;
      }
      error_page   500 502 503 504  /50x.html;
      location = /50x.html {
        root   /usr/share/nginx/html;
      }
    }
  b.conf: |-
    server {
      listen       80;
      server_name  b.mldong.com;
      location / {
        root   /usr/share/nginx/html/b;
        index  index.html index.htm;
      }
      error_page   500 502 503 504  /50x.html;
      location = /50x.html {
        root   /usr/share/nginx/html;
      }
    }
EOF

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Create a command

kubectl apply -f nginx_cm.yaml 
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View all configMaps in the namespace

kubectl get configmap -n mldong-test
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View details about the specified ConfigMap

kubectl describe configmap nginx-cm -n mldong-test
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ConfigMap===>kind

nginx-cm===>metadata.name

mldong-test===>metadata.namespace

Delete the defined ConfigMap

kubectl delete -f nginx_cm.yaml 
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Use external file definitions

Create a.conf and b.C onf in the current directory

a.conf

cat <<EOF > /mldong/k8s/nginx/a.conf
server {
    listen       80;
    server_name  a.mldong.com;
    location / {
        root   /usr/share/nginx/html/a;
        index  index.html index.htm;
    }
    error_page   500 502 503 504  /50x.html;
    location = /50x.html {
    	root   /usr/share/nginx/html;
    }
}
EOF

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b.conf

cat <<EOF > /mldong/k8s/nginx/b.conf
server {
    listen       80;
    server_name  b.mldong.com;
    location / {
        root   /usr/share/nginx/html/b;
        index  index.html index.htm;
    }
    error_page   500 502 503 504  /50x.html;
    location = /50x.html {
    	root   /usr/share/nginx/html;
    }
}
EOF

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Create a command

Create a single

kubectl create configmap nginx-cm --from-file=a.conf -n mldong-test
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Create multiple

kubectl create configmap nginx-cm --from-file=a.conf --from-file=b.conf -n mldong-test
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By default, the file name is key. If you want to change the file name, for example:

kubectl create configmap nginx-cm --from-file=xxxx=a.conf -n mldong-test
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Example Delete the created ConfigMap

kubectl delete configmap nginx-cm -n mldong-test
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View all configMaps in the namespace

kubectl get configmap -n mldong-test
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View details about the specified ConfigMap

kubectl describe configmap nginx-cm -n mldong-test
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ConfigMap===>kind

nginx-cm===>metadata.name

mldong-test===>metadata.namespace

Persistent storage

NFS is used for persistent storage here, and NAS is called on Ali Cloud. If you don’t have one, open it first. – There’s a free version.

Open the nas

Search the nas

Creation Process

The only thing you need to pay attention to is choosing the right area.

Viewing Configuration Details

mount

Copy the mount command and execute it on the small A server

sudo mount -t nfs -o vers=3,nolock,proto=tcp,rsize=1048576,wsize=1048576,hard,timeo=600,retrans=2,noresvport 9fdd94bf87-wkf12.cn-zhangjiakou.nas.aliyuncs.com:/ /mnt
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/ MNT indicates the local directory to be mounted. If the directory does not exist, you need to create it yourself. You can change it to another directory.

View the mounting status

df -h | grep aliyun
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Cancel the mount

umount /mnt
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Memory card

Ali Cloud cluster storage plug-in has two Flexvolume and CSI. CSI is officially recommended. After selecting CSI, the cluster will install the plug-in by default.

…

Before starting, it is recommended to review the documentation completely.

The storage plug-in is installed by default

Verify the installation

Run the following command to display a list of pods in the Running state.

kubectl get pod -n kube-system | grep csi-plugin
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Run the following command to print a list of pods in the Running state.

kubectl get pod -n kube-system | grep csi-provisioner
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Begin to use

This paper first uses NAS static storage volume practice, mainly for fear of getting too much at a time, there will be some chaos. Try it out for yourself, the yamL of this document is flawed. If you can’t, you can create it using the console and learn yamL.

Example Create a NAS static storage volume

nginx-pv.yaml

cat <<EOF > /mldong/k8s/nginx/nginx-pv.yaml
apiVersion: v1
kind: PersistentVolume
metadata:
  name: nginx-pv
  labels:
    alicloud-pvname: nginx-pv
spec:
  capacity:
    storage: 5Gi
  accessModes:
    - ReadWriteMany
  csi:
    driver: nasplugin.csi.alibabacloud.com
    volumeHandle: nginx-pv
    volumeAttributes:
      server: "9fdd94bf87-wfq72.cn-zhangjiakou.nas.aliyuncs.com"
      path: "/"
      vers: "3"
  storageClassName: nas
EOF

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instructions

driver: Driver type. In this example, the value isnasplugin.csi.alibabacloud.com, indicates that the aliyun NAS CSI plug-in is used.
volumeHandle: Sets the PV name.
server: NAS mount point.
path: Mounts subdirectories.
vers: Indicates the VERSION of the NFS protocol to which the NAS data volume is attached. V3 is recommended. Speed NAS only supports V3.

Note: PV is shared by all namespaces, so there is no need to add a namespace

Create the PV

kubectl apply -f nginx-pv.yaml
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Check the PV

kubectl get pv
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Available-> successful, Released-> failed

Viewing PV Details

kubectl describe pv
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Delete the PV

kubectl delete -f nginx-pv.yaml
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nginx-pvc.yaml

Note: PVC has namespaces, so add namespaces

cat <<EOF > /mldong/k8s/nginx/nginx-pvc.yaml
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  annotations:
    pv.kubernetes.io/bind-completed: 'yes'
    pv.kubernetes.io/bound-by-controller: 'yes'
  finalizers:
    - kubernetes.io/pvc-protection
  name: nginx-pvc
  namespace: mldong-test
spec:
  accessModes:
    - ReadWriteMany
  resources:
    requests:
      storage: 1Gi
  selector:
    matchLabels:
      alicloud-pvname: nginx-pv
  storageClassName: nas
  volumeMode: Filesystem
  volumeName: nginx-pv
EOF

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Here the main alicloud-pvname is the PV metadata.name

Create a PVC

kubectl apply -f nginx-pvc.yaml
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Check the PVC

kubectl get pvc -n mldong-test
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Bound-> success, Pending-> failure

View PVC details

kubectl describe pvc -n mldong-test
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Delete the PVC

kubectl delete -f nginx-pvc.yaml
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Began to mount

K8s volumes are defined first and then mounted. We have just defined two types of coupons, ConfigMap and PVC.

cat <<EOF > /mldong/k8s/nginx/nginx-deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-pod
  namespace: mldong-test
spec:
  selector:
    matchLabels:
      app: nginx-pod
  replicas: 1
  template:
    metadata:
      labels:
        app: nginx-pod
    spec:
      containers:
        - name: nginx
          image: registry-vpc.cn-zhangjiakou.aliyuncs.com/mldong/java/nginx:latest
          imagePullPolicy: IfNotPresent
          ports:
            - containerPort: 80
              name: port
              protocol: TCP
          volumeMounts:
            - name: nginx-pvc
              mountPath: "/usr/share/nginx/html"
            - name: nginx-cm
              mountPath: "/etc/nginx/conf.d"
      volumes:
        - name: nginx-pvc
          persistentVolumeClaim: 
            claimName: nginx-pvc
        - name: nginx-cm
          configMap:
            name: nginx-cm
EOF

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Description:

volumeMount.name= = >volumes.name
volumeMount.mountPath==> Container directory
persistentVolumeClaim.claimName==> Name of the DEFINED PVC
configMap.name==> Name of the configMap to be defined
---For file segmentation, K8S will help handle it

Create a pod

kubectl apply -f nginx-deployment.yaml
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Check the pod

kubectl get pods -n mldong-test
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Small A server creates files

├ ─ ─ / MNT ├ ─ ─ a └ ─ ─ index. The HTML └ ─ ─ b └ ─ ─ index. The HTMLCopy the code

Into the container

kubectl exec -it pod-name -n mldong-test --  bash
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Check whether the configuration file exists

ls /etc/nginx/conf.d/
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Check whether static resources exist

ls /usr/share/nginx/html
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Create a Service

file

cat <<EOF > /mldong/k8s/nginx/nginx-service.yaml
apiVersion: v1
kind: Service
metadata:
  name: nginx-nodeport
  namespace: mldong-test
spec:
  type: NodePort
  ports:
  - port: 80
    targetPort: 80
    nodePort: 32180 
  selector:
    app: nginx-pod
EOF

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command

kubectl apply -f nginx-service.yaml
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Look at the Service

kubectl get Service -n mldong-test
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Access the service

Accessing Node 1

curl worker1:32180
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Accessing Node 2

curl worker2:32180
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Access domain name A

curl -H 'Host: a.mldong.com' worker1:32180
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Accessing domain name B

curl -H 'Host: b.mldong.com' worker1:32180
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summary

This article uses Nginx as an example to show you how to use ConfigMap and persistent storage, although it is cloud-based, the basic flow is similar.

Determine the storage type of the service to be deployed
If it is ConfigMap
- Define the configuration
If the pv
- Define the pv
- Definition of PVC
Define the POD mount
Define service To publish a service

Walk you through K8S – cluster creation and Hello World

Take you through K8S-ConfigMap and persistent storage

preface

Nginx storage type analysis

The configuration file

Static resource

ConfigMap

Use YAML to define the mode

Define a single

Define multiple

Create a command

View all configMaps in the namespace

View details about the specified ConfigMap

Delete the defined ConfigMap

Use external file definitions

Create a command

Create a single

Create multiple

Example Delete the created ConfigMap

View all configMaps in the namespace

View details about the specified ConfigMap

Persistent storage

Open the nas

Search the nas

Viewing Configuration Details

mount

View the mounting status

Cancel the mount

Memory card

Verify the installation

Begin to use

Example Create a NAS static storage volume

Create the PV

Check the PV

Viewing PV Details

Delete the PV

Create a PVC

Check the PVC

View PVC details

Delete the PVC

Began to mount

Create a pod

Check the pod

Small A server creates files

Into the container

Check whether the configuration file exists

Check whether static resources exist

Create a Service

command

Look at the Service

Access the service

Accessing Node 1

Accessing Node 2

Access domain name A

Accessing domain name B

summary

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