kind installation and use

Posted by apulmca2k4 on Wed, 17 Nov 2021 11:32:47 +0100

  • Tips: after the following command is installed, you will be familiar with it by trying it several times
  • kind installation
curl -Lo ./kind https://kind.sigs.k8s.io/dl/v0.9.0/kind-linux-amd64
chmod +x ./kind
mv ./kind /${some-dir-in-your-PATH}/kind
  • kubectl installation
curl -LO "https://dl.k8s.io/release/$(curl -L -s https://dl.k8s.io/release/stable.txt)/bin/linux/amd64/kubectl"
chmod +x kubectl
mkdir -p ~/.local/bin/kubectl
mv ./kubectl ~/.local/bin/kubectl
  • Create a default cluster:
kind create cluster
  • Create from mirror:
kind create cluster --image kindest/node:latest
  • View cluster
kind get cluster
  • Get node
kind get nodes
  • Delete default cluster
kind delete cluster
  • Delete cluster by name
kind delete cluster --name clusterName
  • Delete all clusters
kind delete clusters --all

  • Setting the context for kubectl means viewing the available clusters, which is equivalent to the cluster list

kubectl config get-contexts

CURRENT   NAME              CLUSTER           AUTHINFO          NAMESPACE
*         kind-my-cluster   kind-my-cluster   kind-my-cluster
  • Switch cluster
# After viewing the cluster list, switch the context as needed
kubectl config set-context clusterName
 perhaps

kubectl cluster-info --context clusterName
  • Load the image into kind's node, which is mainly used where there is no network
kind load docker-image nginx --name kind
  • Configuring a multi node cluster: kind_cluster.yaml
kind: Cluster
apiVersion: kind.x-k8s.io/v1alpha4
name: my-cluster

# 1 control plane node and 3 workers
nodes:
# the control plane node config
- role: control-plane
# the three workers
- role: worker
- role: worker
- role: worker

Create: kind create cluster --config=kind-config.yaml  , You can add to the command you create   -- Name my cluster, but try to write it into yaml to facilitate later use

View node

kubectl get nodes  
                           
#NAME                       STATUS   ROLES    AGE   VERSION
#my-cluster-control-plane   Ready    master   48m   v1.19.1
#my-cluster-worker          Ready    <none>   47m   v1.19.1
#my-cluster-worker2         Ready    <none>   47m   v1.19.1
#my-cluster-worker3         Ready    <none>   47m   v1.19.1

Multiple control surfaces

Generally, a kubernetes used in production will use multiple control planes to ensure high availability. Using kind config can easily create a kubernetes cluster with multiple control planes. Use the following command to create a cluster of 3 control surfaces and 3 work nodes:

# this config file contains all config fields with comments
# NOTE: this is not a particularly useful config file
kind: Cluster
apiVersion: kind.x-k8s.io/v1alpha4

nodes:
# the control plane node config
- role: control-plane
- role: control-plane
- role: control-plane
# the three workers
- role: worker
- role: worker
- role: worker

You can see three control surfaces:

# kubectl get node
NAME                  STATUS   ROLES    AGE   VERSION
kind-control-plane    Ready    master   15m   v1.19.1
kind-control-plane2   Ready    master   14m   v1.19.1
kind-control-plane3   Ready    master   13m   v1.19.1
kind-worker           Ready    <none>   12m   v1.19.1
kind-worker2          Ready    <none>   12m   v1.19.1
kind-worker3          Ready    <none>   12m   v1.19.1

Specify the version of Kubernetes

You can modify the version of kubernetes by specifying the mirror version of node. Can be in On the official release page If you need to find a mirror tag in, it is recommended to bring sha with the tag, such as

kindest/node:v1.19.1@sha256:98cf5288864662e37115e362b23e4369c8c4a408f99cbc06e58ac30ddc721600

kind: Cluster
apiVersion: kind.x-k8s.io/v1alpha4
nodes:
- role: control-plane
  image: kindest/node:v1.16.4@sha256:b91a2c2317a000f3a783489dfb755064177dbc3a0b2f4147d50f04825d016f55
- role: worker
  image: kindest/node:v1.16.4@sha256:b91a2c2317a000f3a783489dfb755064177dbc3a0b2f4147d50f04825d016f55

Map the port of node to the host

You can map the port of node to the host and port 80 of container to port 80 of host in the following way:

kind: Cluster
apiVersion: kind.x-k8s.io/v1alpha4
nodes:
- role: control-plane
  extraPortMappings:
  - containerPort: 80
    hostPort: 80
    listenAddress: "0.0.0.0" # Optional, defaults to "0.0.0.0"
    protocol: udp # Optional, defaults to tcp

One disadvantage of kind's update to the cluster (such as enabling IPv6, configuring nodeport, etc.) is that the configuration can only be "updated" by re creating the cluster. At present, the official does not support the update operation of the control surface. Please refer to this issue . See for more configurations Official documents.

ingress deployment

You can forward traffic from the host to the node's ingress controller through the extraport mapping configuration option of KIND.

You can set custom node labels through kubedm's InitConfiguration to use for the nodeSelector of the ingress controller.

Create cluster

Using extraPortMappings   Create a cluster with node labels.

cat <<EOF | kind create cluster --config=-
kind: Cluster
apiVersion: kind.x-k8s.io/v1alpha4
nodes:
- role: control-plane
  kubeadmConfigPatches:
  - |
    kind: InitConfiguration
    nodeRegistration:
      kubeletExtraArgs:
        node-labels: "ingress-ready=true"
  extraPortMappings:
  - containerPort: 80
    hostPort: 80
    protocol: TCP
  - containerPort: 443
    hostPort: 443
    protocol: TCP
EOF

Deploy ingress controller

The inress controllers supported by kind are as follows:

Next, deploy NGINX ingress.

kubectl apply -f https://raw.githubusercontent.com/kubernetes/ingress-nginx/master/deploy/static/provider/kind/deploy.yaml

During the deployment of ingree, you may encounter that the secret cannot be found   Ingress nginx admission. The reason for this problem may be that the following two job s cannot be started normally. See this issue . If the external network image cannot be pulled, you can first download the deploy.yaml file to the local host, manually load the image to the local host, and then use the kind load docker image command mentioned above to load the image to the node.

Test ingress

Create as follows resources: kubectl apply -f usage.yaml

kind: Pod
apiVersion: v1
metadata:
  name: foo-app
  labels:
    app: foo
spec:
  containers:
  - name: foo-app
    image: hashicorp/http-echo:0.2.3
    args:
    - "-text=foo"
---
kind: Service
apiVersion: v1
metadata:
  name: foo-service
spec:
  selector:
    app: foo
  ports:
  # Default port used by the image
  - port: 5678
---
kind: Pod
apiVersion: v1
metadata:
  name: bar-app
  labels:
    app: bar
spec:
  containers:
  - name: bar-app
    image: hashicorp/http-echo:0.2.3
    args:
    - "-text=bar"
---
kind: Service
apiVersion: v1
metadata:
  name: bar-service
spec:
  selector:
    app: bar
  ports:
  # Default port used by the image
  - port: 5678
---
apiVersion: networking.k8s.io/v1beta1
kind: Ingress
metadata:
  name: example-ingress
spec:
  rules:
  - http:
      paths:
      - path: /foo
        backend:
          serviceName: foo-service
          servicePort: 5678
      - path: /bar
        backend:
          serviceName: bar-service
          servicePort: 5678
---

At the remote curl, the foo and bar services on the host can see that the network is connected. At this time, the nodeport 80 exposed by ingress through kind configuration extraPortMappings is used.

C:\Users\liuch>curl 192.168.100.11/foo
foo

C:\Users\liuch>curl 192.168.100.11/bar
bar

Summary:

Kind is a very convenient kubernetes deployment tool, which can quickly deploy multiple kubernetes clusters. However, there are some implementation flaws. For example, kind does not support cluster upgrading, and the process of manually loading images is also troublesome. However, in terms of overall use, the flaws are not hidden.

FAQ:

  • The connection to the server localhost: 8080 was rejected - did you specify the right host or port?, Moreover, the cluster cannot be successfully switched by using commands such as kubectl config use context kind kind.

    You can view the supported context names in the / root/.kube/config file (for example, the context used below is kind kind), and then use kubectl config use context kind kind:

    apiVersion: v1
clusters:
- cluster:
    certificate-authority-data: ...
    server: https://127.0.0.1:39923
  name: kind-kind
contexts:
- context:
    cluster: kind-kind
    user: kind-kind
  name: kind-kind
current-context: kind-kind
kind: Config
preferences: {}
users:
- name: kind-kind
  user:
    client-certificate-data: ...

  • The default address of apiservice created by kind is 127.0.0.1 and cannot be connected remotely. You can use the following mode , modify the address and port of apiservice

    kind: Cluster
apiVersion: kind.x-k8s.io/v1alpha4
networking:
  
  apiServerPort: 6000

  • If kind fails to connect, you can check whether there are other docker network impacts

     

Topics: Go Kubernetes Cloud Native

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