k8s基础操作命令

K8s重新加入节点

1.重置node节点环境在slave节点上执行

[root@node2 ~]# kubeadm reset

[reset] WARNING: changes made to this host by 'kubeadm init' or 'kubeadm join' will be reverted.
[reset] are you sure you want to proceed? [y/N]: y
[preflight] running pre-flight checks
[reset] stopping the kubelet service
[reset] unmounting mounted directories in "/var/lib/kubelet"
[reset] removing kubernetes-managed containers
[reset] cleaning up running containers using crictl with socket /var/run/dockershim.sock
[reset] failed to list running pods using crictl: exit status . Trying to use docker instead[reset] no etcd manifest found in "/etc/kubernetes/manifests/etcd.yaml". Assuming external etcd
[reset] deleting contents of stateful directories: [/var/lib/kubelet /etc/cni/net.d /var/lib/dockershim /var/run/kubernetes]
[reset] deleting contents of config directories: [/etc/kubernetes/manifests /etc/kubernetes/pki]
[reset] deleting files: [/etc/kubernetes/admin.conf /etc/kubernetes/kubelet.conf /etc/kubernetes/bootstrap-kubelet.conf /etc/kubernetes/controller-manager.conf /etc/kubernetes/scheduler.conf]

reset

2.关闭slave节点的交换分区

[root@node3 ~]# swapoff  -a

处理token和CA证书过期

1.在master上执行

[root@k8s-master ~]# openssl x509 -pubkey -in /etc/kubernetes/pki/ca.crt | openssl rsa -pubin -outform der >/dev/null | openssl dgst -sha256 -hex | sed 's/^.* //'
5a949445e86e76a060f6c3a6c2f571df4361085387cde7068493b418d484bb14
[root@k8s-master ~]# kubeadm token create
lsv2rv.7q0or3flbjne8s0k

2.在slave上执行

[root@node2 ~]# kubeadm join 192.168.11.141: --token lsv2rv.7q0or3flbjne8s0k  --discovery-token-ca-cert-hash sha256:5a949445e86e76a060f6c3a6c2f571df4361085387cde7068493b418d484bb14

[preflight] running pre-flight checks
    [WARNING RequiredIPVSKernelModulesAvailable]: the IPVS proxier will not be used, because the following required kernel modules are not loaded: [ip_vs ip_vs_rr ip_vs_wrr ip_vs_sh] or no builtin kernel ipvs support: map[ip_vs_wrr:{} ip_vs_sh:{} nf_conntrack_ipv4:{} ip_vs:{} ip_vs_rr:{}]
you can solve this problem with following methods:
 . Run 'modprobe -- ' to load missing kernel modules;
. Provide the missing builtin kernel ipvs support

I0517 ::53.384827     kernel_validator.go:] Validating kernel version
I0517 ::53.384903     kernel_validator.go:] Validating kernel config
    [WARNING Hostname]: hostname "node2" could not be reached
    [WARNING Hostname]: hostname "node2" lookup node2 on 192.168.11.2:: no such host
[discovery] Trying to connect to API Server "192.168.11.141:6443"
[discovery] Created cluster-info discovery client, requesting info from "https://192.168.11.141:6443"
[discovery] Requesting info from "https://192.168.11.141:6443" again to validate TLS against the pinned public key
[discovery] Cluster info signature and contents are valid and TLS certificate validates against pinned roots, will use API Server "192.168.11.141:6443"
[discovery] Successfully established connection with API Server "192.168.11.141:6443"
[kubelet] Downloading configuration for the kubelet from the "kubelet-config-1.11" ConfigMap in the kube-system namespace
[kubelet] Writing kubelet configuration to file "/var/lib/kubelet/config.yaml"
[kubelet] Writing kubelet environment file with flags to file "/var/lib/kubelet/kubeadm-flags.env"
[preflight] Activating the kubelet service
[tlsbootstrap] Waiting for the kubelet to perform the TLS Bootstrap...
[patchnode] Uploading the CRI Socket information "/var/run/dockershim.sock" to the Node API object "node2" as an annotation

This node has joined the cluster:
* Certificate signing request was sent to master and a response
  was received.
* The Kubelet was informed of the new secure connection details.

Run 'kubectl get nodes' on the master to see this node join the cluster.

3.kubectl命令过期

#  rm -fr $HOME/.kube/config
   # cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
   # sudo chown $(id -u):$(id -g) $HOME/.kube/config

k8s命令实例

pod的创建和删除

[root@k8s-master ~]#kubectl run nginx-deploy --image=nginx:1.14-alpine --port= --replicas=

[root@k8s-master ~]# kubectl get pods -o wide
NAME                          READY     STATUS    RESTARTS   AGE       IP            NODE
nginx-deploy-5b595999-d7rpg   /       Running             226d      10.244.1.11   node2
nginx-deploy-5b595999-sdfcz   /       Running             226d      10.244.1.10   node2

[root@node2 ~]# curl 10.244.1.11
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>

[root@k8s-master ~]# kubectl delete pods nginx-deploy-5b595999-sdfcz
pod "nginx-deploy-5b595999-sdfcz" deleted
[root@k8s-master ~]# kubectl get pods -o wide
NAME                          READY     STATUS              RESTARTS   AGE       IP            NODE
nginx-deploy-5b595999-d7rpg   /       Running                       226d      10.244.1.11   node2
nginx-deploy-5b595999-s4cjv   /       ContainerCreating             4s        <none>        node3
[root@k8s-master ~]# kubectl get pods -o wide
NAME                          READY     STATUS    RESTARTS   AGE       IP            NODE
nginx-deploy-5b595999-d7rpg   /       Running             226d      10.244.1.11   node2
nginx-deploy-5b595999-s4cjv   /       Running             25s       10.244.2.5    node3

service的管理

service是用来为pod提供固定访问端点的
   service地址是通过iptables或者ipvs规则来实现的 不能直接ping通      但是却可以通过地址访问到对应的服务

[root@k8s-master ~]# kubectl run myapp --image=ikubernetes/myapp:v1 --replicas=
deployment.apps/myapp created
[root@k8s-master ~]# kubectl get deployment
NAME           DESIRED   CURRENT   UP-TO-DATE   AVAILABLE   AGE
myapp                                                   14s
nginx-deploy                                            226d
[root@k8s-master ~]# kubectl get deployment -w
NAME           DESIRED   CURRENT   UP-TO-DATE   AVAILABLE   AGE
myapp                                                   23s
nginx-deploy                                            226d
myapp                                         55s
myapp                                         1m
^C[root@k8s-master ~]# kubectl get pods
NAME                          READY     STATUS    RESTARTS   AGE
myapp-848b5b879b-9kd6s        /       Running             1m
myapp-848b5b879b-dvtgn        /       Running             1m
nginx-deploy-5b595999-d7rpg   /       Running             226d
nginx-deploy-5b595999-s4cjv   /       Running             56m
[root@k8s-master ~]# kubectl get pods -o wide
NAME                          READY     STATUS    RESTARTS   AGE       IP            NODE
myapp-848b5b879b-9kd6s        /       Running             1m        10.244.2.6    node3
myapp-848b5b879b-dvtgn        /       Running             1m        10.244.1.12   node2
nginx-deploy-5b595999-d7rpg   /       Running             226d      10.244.1.11   node2
nginx-deploy-5b595999-s4cjv   /       Running             57m       10.244.2.5    node3
[root@k8s-master ~]# wget -O - -q 10.244.2.6
Hello MyApp | Version: v1 | <a href="hostname.html">Pod Name</a>
[root@k8s-master ~]# kubectl expose deployment myapp --name=myapp --port=
service/myapp exposed
[root@k8s-master ~]# kubectl get svc
NAME         TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)   AGE
kubernetes   ClusterIP   10.96.0.1        <none>        /TCP   226d
myapp        ClusterIP   10.101.171.64    <none>        /TCP    8s
nginx        ClusterIP   10.106.232.252   <none>        /TCP    6m
[root@k8s-master ~]# kubectl scale --replicas= deployment=myapp
error: resource(s) were provided, but no name, label selector, or --all flag specified
[root@k8s-master ~]# kubectl scale --replicas= deployment myapp
deployment.extensions/myapp scaled
[root@k8s-master ~]# kubectl get pods
NAME                          READY     STATUS              RESTARTS   AGE
client                        /       Running                       5m
myapp-848b5b879b-5vqx5        /       ContainerCreating             12s
myapp-848b5b879b-98pht        /       ContainerCreating             12s
myapp-848b5b879b-9kd6s        /       Running                       10m
myapp-848b5b879b-dvtgn        /       Running                       10m
myapp-848b5b879b-s6bjh        /       ContainerCreating             12s
nginx-deploy-5b595999-d7rpg   /       Running                       226d
nginx-deploy-5b595999-s4cjv   /       Running                       1h
[root@k8s-master ~]# kubectl get pods
NAME                          READY     STATUS    RESTARTS   AGE
client                        /       Running             5m
myapp-848b5b879b-5vqx5        /       Running             15s
myapp-848b5b879b-98pht        /       Running             15s
myapp-848b5b879b-9kd6s        /       Running             10m
myapp-848b5b879b-dvtgn        /       Running             10m
myapp-848b5b879b-s6bjh        /       Running             15s
nginx-deploy-5b595999-d7rpg   /       Running             226d
nginx-deploy-5b595999-s4cjv   /       Running             1h
[root@k8s-master ~]# kubectl scale --replicas= deployment myapp
deployment.extensions/myapp scaled
[root@k8s-master ~]# kubectl get pods
NAME                          READY     STATUS    RESTARTS   AGE
client                        /       Running             5m
myapp-848b5b879b-5vqx5        /       Running             30s
myapp-848b5b879b-9kd6s        /       Running             10m
myapp-848b5b879b-dvtgn        /       Running             10m
nginx-deploy-5b595999-d7rpg   /       Running             226d
nginx-deploy-5b595999-s4cjv   /       Running             1h
[root@k8s-master ~]# kubectl set image deployment myapp myapp=ikubernetes/myapp:v2
deployment.extensions/myapp image updated
[root@k8s-master ~]# kubectl get pods
NAME                          READY     STATUS              RESTARTS   AGE
client                        /       Running                       9m
myapp-74c94dcb8c-mjjpw        /       ContainerCreating             14s
myapp-848b5b879b-5vqx5        /       Running                       4m
myapp-848b5b879b-9kd6s        /       Running                       14m
myapp-848b5b879b-dvtgn        /       Running                       14m
nginx-deploy-5b595999-d7rpg   /       Running                       226d
nginx-deploy-5b595999-s4cjv   /       Running                       1h
[root@k8s-master ~]# kubectl get pods
NAME                          READY     STATUS              RESTARTS   AGE
client                        /       Running                       10m
myapp-74c94dcb8c-l2j8v        /       ContainerCreating             32s
myapp-74c94dcb8c-mjjpw        /       Running                       1m
myapp-848b5b879b-9kd6s        /       Running                       15m
myapp-848b5b879b-dvtgn        /       Running                       15m
nginx-deploy-5b595999-d7rpg   /       Running                       226d
nginx-deploy-5b595999-s4cjv   /       Running                       1h
[root@k8s-master ~]# kubectl get pods
NAME                          READY     STATUS    RESTARTS   AGE
client                        /       Running             11m
myapp-74c94dcb8c-dhhln        /       Running             1m
myapp-74c94dcb8c-l2j8v        /       Running             1m
myapp-74c94dcb8c-mjjpw        /       Running             2m
nginx-deploy-5b595999-d7rpg   /       Running             226d
nginx-deploy-5b595999-s4cjv   /       Running             1h
[root@k8s-master ~]# kubectl edit svc myapp
 修改service的type ClusterType 改成NodePort

service/myapp edited
[root@k8s-master ~]# kubectl get svc
NAME         TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)        AGE
kubernetes   ClusterIP   10.96.0.1        <none>        /TCP        226d
myapp        NodePort    10.101.171.64    <none>        :/TCP   19m
nginx        ClusterIP   10.106.232.252   <none>        /TCP         25m

通过service可以把服务映射到集群中的任何一个节点上