官方文档：
https://kubernetes.io/zh-cn/docs/reference/kubectl/
https://kubernetes.io/zh-cn/docs/reference/kubectl/cheatsheet/
https://kubernetes.io/docs/reference/generated/kubectl/kubectl-commands#get
当我们不知道如何管理一个资源（yaml）的时候，可以通过这个参数获取帮助
[root@k8s-harbor01 ~]# kubectl explain po # 这里会显示，关于pod的yaml该怎么写
KIND: Pod
VERSION: v1
DESCRIPTION:
Pod is a collection of containers that can run on a host. This resource is
created by clients and scheduled onto hosts.
FIELDS:
apiVersion <string>
APIVersion defines the versioned schema of this representation of an
object. Servers should convert recognized schemas to the latest internal
value, and may reject unrecognized values. More info:
https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#resources
kind <string>
Kind is a string value representing the REST resource this object
represents. Servers may infer this from the endpoint the client submits
requests to. Cannot be updated. In CamelCase. More info:
https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#types-kinds
metadata <Object>
Standard object's metadata. More info:
https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#metadata
spec <Object>
Specification of the desired behavior of the pod. More info:
https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#spec-and-status
status <Object>
Most recently observed status of the pod. This data may not be up to date.
Populated by the system. Read-only. More info:
https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#spec-and-status
# 并且，当我们写到某一个阶段的时候，不知道有些什么参数，也可以用explain查
[root@k8s-harbor01 ~]# kubectl explain po.spec.volumes
KIND: Pod
VERSION: v1
RESOURCE: volumes <[]Object>
…………省略部分内容
# yaml中是有缩进和上下级关系的，上面的explain换成yaml就是这样
sepc:
volumes:
开两个窗口，一个查，一个写yaml
[root@k8s-harbor01 ~]# kubectl explain ns # 下面查出来的值，都是最顶级的，不用缩进
KIND: Namespace
VERSION: v1
DESCRIPTION:
Namespace provides a scope for Names. Use of multiple namespaces is
optional.
FIELDS:
apiVersion <string>
APIVersion defines the versioned schema of this representation of an
object. Servers should convert recognized schemas to the latest internal
value, and may reject unrecognized values. More info:
https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#resources
kind <string>
Kind is a string value representing the REST resource this object
represents. Servers may infer this from the endpoint the client submits
requests to. Cannot be updated. In CamelCase. More info:
https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#types-kinds
metadata <Object>
Standard object's metadata. More info:
https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#metadata
spec <Object>
Spec defines the behavior of the Namespace. More info:
https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#spec-and-status
status <Object>
Status describes the current status of a Namespace. More info:
https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#spec-and-status
[root@k8s-harbor01 yaml]# vim ns-myserver.yaml
apiVersion: v1
kind: # 这里不知道类型有些什么，就继续通过explain查
[root@k8s-harbor01 ~]# kubectl explain ns.kind
KIND: Namespace # 这里就是我们要写的类型
VERSION: v1
FIELD: kind <string>
DESCRIPTION:
Kind is a string value representing the REST resource this object
represents. Servers may infer this from the endpoint the client submits
requests to. Cannot be updated. In CamelCase. More info:
https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#types-kinds
[root@k8s-harbor01 yaml]# cat ns-myserver.yaml # 如果没有其他去求，这个创建ns的yaml就已经写完了
apiVersion: v1
kind: Namespace
名称、端口等都属于元数据，所以要查metadata字段
[root@k8s-harbor01 ~]# [root@k8s-harbor01 ~]# kubectl explain ns.metadata|grep name # 内容太多 过滤下
name <string>
Name must be unique within a namespace. Is required when creating
generation of an appropriate name automatically. Name is primarily intended
More info: http://kubernetes.io/docs/user-guide/identifiers#names
[root@k8s-harbor01 yaml]# cat ns-myserver.yaml # 如果没有其他去求，这个创建ns的yaml就已经写完了
apiVersion: v1
kind: Namespace
metadata:
name: myserver
[root@k8s-harbor01 yaml]# kubectl apply -f ns-myserver.yaml
namespace/myserver created
[root@k8s-harbor01 yaml]# kubectl get ns |grep myserver
myserver Active 6s
查询集群中的各种资源信息
[root@k8s-harbor01 yaml]# kubectl get --help # 获取帮助
其他资源类型的查看方式基本也都一样
[root@k8s-harbor01 yaml]# kubectl get deploy # 默认查看default名称空间下的资源
No resources found in default namespace.
[root@k8s-harbor01 yaml]# kubectl get deploy -A # -A表示查看所有名称空间下的资源
NAMESPACE NAME READY UP-TO-DATE AVAILABLE AGE
kube-system calico-kube-controllers 1/1 1 1 18h
kube-system coredns 2/2 2 2 18h
[root@k8s-harbor01 yaml]# kubectl get deploy -n kube-system # -n 查看指定名称空间下的资源
NAME READY UP-TO-DATE AVAILABLE AGE
calico-kube-controllers 1/1 1 1 18h
coredns 2/2 2 2 18h
这种方式不易读，但是方便脚本处理
[root@k8s-harbor01 yaml]# kubectl get deploy -o -n kube-system # 这种方式会输出指定名称空间下的所有内容
[root@k8s-harbor01 yaml]# kubectl get deploy -n kube-system coredns -o json # 可以通过这种方式查看某一个资源
[root@k8s-harbor01 yaml]# kubectl get deploy -n kube-system coredns -o yaml
node是全局资源，不受ns限制
[root@k8s-harbor01 yaml]# kubectl get no # 查看方式大同小异，可以查看单独一个，也可以输出json和yaml格式
NAME STATUS ROLES AGE VERSION
k8s-master01 Ready,SchedulingDisabled master 18h v1.26.1
k8s-master02 Ready,SchedulingDisabled master 18h v1.26.1
k8s-master03 Ready,SchedulingDisabled master 18h v1.26.1
k8s-node01 Ready node 18h v1.26.1
k8s-node02 Ready node 18h v1.26.1
k8s-node03 Ready node 18h v1.26.1
其他资源类型操作也一样的
[root@k8s-harbor01 yaml]# kubectl describe po net-test3
…………省略部分内容
Events: # 这个东西很重要，会显示一定时间内的pod事件，正常的不正常的都会记录，主要看 Message这一列
Type Reason Age From Message
---- ------ ---- ---- -------
Normal Scheduled 7s default-scheduler Successfully assigned default/net-test3 to k8s-node02
Normal Pulled 6s kubelet Container image "10.31.200.104/myserver/centos:7.9.2009" already present on machine
Normal Created 6s kubelet Created container net-test3
Normal Started 6s kubelet Started container net-test3
[root@k8s-harbor01 yaml]# kubectl describe no k8s-node03
# 下面列举的都是一下日常工作中关注的比较多的东西
Labels: beta.kubernetes.io/arch=amd64
beta.kubernetes.io/os=linux
kubernetes.io/arch=amd64
kubernetes.io/hostname=k8s-node03
kubernetes.io/os=linux
kubernetes.io/role=node
Taints: <none>
Namespace Name CPU Requests CPU Limits Memory Requests Memory Limits Age
--------- ---- ------------ ---------- --------------- ------------- ---
default net-test1 0 (0%) 0 (0%) 0 (0%) 0 (0%) 19h
kube-system calico-node-bcpqf 250m (12%) 0 (0%) 0 (0%) 0 (0%) 19h
kube-system coredns-5879bb4b8c-g8z8b 100m (5%) 200m (10%) 70Mi (1%) 256Mi (7%) 19h
Allocated resources:
(Total limits may be over 100 percent, i.e., overcommitted.)
Resource Requests Limits
-------- -------- ------
cpu 350m (17%) 200m (10%)
memory 70Mi (1%) 256Mi (7%)
ephemeral-storage 0 (0%) 0 (0%)
hugepages-1Gi 0 (0%) 0 (0%)
hugepages-2Mi 0 (0%) 0 (0%)
Events: <none>
logs只能看到标准输出和错误输出（/dev/stdout、/dev/stderr），非这两种类型的，只能进入容器查看
如官方的nginx：dockerfile中就有，ln -sf /dev/stdout /var/log/access.log、ln -sf /dev/stderr /var/log/error.log
不推荐这种方式，pod日志太多，会直接卡死终端
[root@k8s-harbor01 yaml]# kubectl logs -n kube-system calico-node-bcpqf
这个也不推荐
[root@k8s-harbor01 yaml]# kubectl logs -f -n kube-system calico-node-bcpqf
这种方式还可以
[root@k8s-harbor01 yaml]# kubectl logs -f --tail 100 -n kube-system calico-node-bcpqf
这种方式还可以
[root@k8s-harbor01 yaml]# kubectl logs -n kube-system calico-node-bcpqf | less
[root@k8s-harbor01 ~]# kubectl exec net-test2 -- cat /etc/hosts
# Kubernetes-managed hosts file.
127.0.0.1 localhost
::1 localhost ip6-localhost ip6-loopback
fe00::0 ip6-localnet
fe00::0 ip6-mcastprefix
fe00::1 ip6-allnodes
fe00::2 ip6-allrouters
10.200.85.195 net-test2
[root@k8s-harbor01 ~]# kubectl exec -it net-test2 -- /bin/bash
kubectl delete -f app.yaml
kubectl delete $资源名称
工作中不常用，更推荐apply
kucectl create -f app.yaml
支持从yaml或json格式文件、标准输入、或指定URL创建资源对象
kucectl apply -f app.yaml
kucectl apply -f https://xxx.yaml
kucectl apply -k dir/ # 执行指定目录下的所有yaml
[root@k8s-harbor01 ~]# kubectl cluster-info
Kubernetes control plane is running at https://10.31.200.100:6443
CoreDNS is running at https://10.31.200.100:6443/api/v1/namespaces/kube-system/services/kube-dns:dns/proxy
[root@k8s-harbor01 ~]# kubectl get no
NAME STATUS ROLES AGE VERSION
k8s-master01 Ready,SchedulingDisabled master 43h v1.26.1
k8s-master02 Ready,SchedulingDisabled master 43h v1.26.1
k8s-master03 Ready,SchedulingDisabled master 43h v1.26.1
k8s-node01 Ready node 43h v1.26.1
k8s-node02 Ready node 43h v1.26.1
k8s-node03 Ready node 43h v1.26.1
[root@k8s-harbor01 ~]# kubectl cordon k8s-node01
node/k8s-node01 cordoned
[root@k8s-harbor01 ~]# kubectl get no
NAME STATUS ROLES AGE VERSION
k8s-master01 Ready,SchedulingDisabled master 43h v1.26.1
k8s-master02 Ready,SchedulingDisabled master 43h v1.26.1
k8s-master03 Ready,SchedulingDisabled master 43h v1.26.1
k8s-node01 Ready,SchedulingDisabled node 43h v1.26.1 # 这样就关闭调度了
k8s-node02 Ready node 43h v1.26.1
k8s-node03 Ready node 43h v1.26.1
一般是配合上面的命令使用
[root@k8s-harbor01 ~]# kubectl uncordon k8s-node01
node/k8s-node01 uncordoned
[root@k8s-harbor01 ~]# kubectl get no
NAME STATUS ROLES AGE VERSION
k8s-master01 Ready,SchedulingDisabled master 43h v1.26.1
k8s-master02 Ready,SchedulingDisabled master 43h v1.26.1
k8s-master03 Ready,SchedulingDisabled master 43h v1.26.1
k8s-node01 Ready node 43h v1.26.1 # 这样就又可以调度了
k8s-node02 Ready node 43h v1.26.1
k8s-node03 Ready node 43h v1.26.1
清空节点以准备维护。一般是先关闭节点调度，再进行驱逐操作
注意：不能驱逐没有控制器的资源（如单纯的pod）和daemonset控制器管理的pod，除非添加参数
[root@k8s-harbor01 ~]# kubectl cordon k8s-node01 # 关闭node01的调度
node/k8s-node01 cordoned
[root@k8s-harbor01 ~]# kubectl get po -o wide -A |grep node01 # 可以看到有3个pod运行在node01上
default net-test2 1/1 Running 0 43h 10.200.85.195 k8s-node01 <none> <none>
kube-system calico-node-cf7xm 1/1 Running 0 43h 10.31.200.110 k8s-node01 <none> <none>
kube-system coredns-5879bb4b8c-tjhhk 1/1 Running 0 43h 10.200.85.194 k8s-node01 <none> <none>
[root@k8s-harbor01 ~]# kubectl drain k8s-node01 # 驱逐node01上的pod
node/k8s-node01 already cordoned
error: unable to drain node "k8s-node01" due to error:[cannot delete Pods declare no controller (use --force to override): default/net-test2, cannot delete DaemonSet-managed Pods (use --ignore-daemonsets to ignore): kube-system/calico-node-cf7xm], continuing command...
There are pending nodes to be drained:
k8s-node01
cannot delete Pods declare no controller (use --force to override): default/net-test2
cannot delete DaemonSet-managed Pods (use --ignore-daemonsets to ignore): kube-system/calico-node-cf7xm
[root@k8s-harbor01 ~]# kubectl drain k8s-node01 --force --ignore-daemonsets
node/k8s-node01 already cordoned
Warning: deleting Pods that declare no controller: default/net-test2; ignoring DaemonSet-managed Pods: kube-system/calico-node-cf7xm
evicting pod kube-system/coredns-5879bb4b8c-tjhhk
evicting pod default/net-test2
pod/coredns-5879bb4b8c-tjhhk evicted
pod/net-test2 evicted
node/k8s-node01 drained
[root@k8s-harbor01 ~]# kubectl get po -o wide -A |grep node01 # 这样就只剩一个calico pod了
kube-system calico-node-cf7xm 1/1 Running 0 43h 10.31.200.110 k8s-node01 <none> <no
主要是实现pod亲和性和反亲和性的
这个后面讲
[root@k8s-harbor01 ~]# kubectl taint --help
就是显示各种资源类型，简称、支持的apiversion版本
[root@k8s-harbor01 ~]# kubectl api-resources |grep 'deployments'
NAME SHORTNAMES APIVERSION NAMESPACED KIND
deployments deploy apps/v1 true Deployment
还是上面的更加适用
[root@k8s-harbor01 ~]# kubectl api-versions
admissionregistration.k8s.io/v1
apiextensions.k8s.io/v1
apiregistration.k8s.io/v1
apps/v1
authentication.k8s.io/v1
authorization.k8s.io/v1
autoscaling/v1
autoscaling/v2
batch/v1
certificates.k8s.io/v1
coordination.k8s.io/v1
discovery.k8s.io/v1
events.k8s.io/v1
flowcontrol.apiserver.k8s.io/v1beta2
flowcontrol.apiserver.k8s.io/v1beta3
networking.k8s.io/v1
node.k8s.io/v1
policy/v1
rbac.authorization.k8s.io/v1
scheduling.k8s.io/v1
storage.k8s.io/v1
storage.k8s.io/v1beta1
v1
[root@k8s-harbor01 ~]# kubectl version --short
Flag --short has been deprecated, and will be removed in the future. The --short output will become the default.
Client Version: v1.26.1
Kustomize Version: v4.5.7
Server Version: v1.26.1
[root@k8s-harbor01 ~]# kubectl version --output=yaml
clientVersion:
buildDate: "2023-01-18T15:58:16Z"
compiler: gc
gitCommit: 8f94681cd294aa8cfd3407b8191f6c70214973a4
gitTreeState: clean
gitVersion: v1.26.1
goVersion: go1.19.5
major: "1"
minor: "26"
platform: linux/amd64
kustomizeVersion: v4.5.7
serverVersion:
buildDate: "2023-01-18T15:51:25Z"
compiler: gc
gitCommit: 8f94681cd294aa8cfd3407b8191f6c70214973a4
gitTreeState: clean
gitVersion: v1.26.1
goVersion: go1.19.5
major: "1"
minor: "26"
platform: linux/amd64
[root@k8s-harbor01 ~]# kubectl config
Modify kubeconfig files using subcommands like "kubectl config set current-context my-context"
The loading order follows these rules:
1. If the --kubeconfig flag is set, then only that file is loaded. The flag may only be set once and no merging takes
place.
2. If $KUBECONFIG environment variable is set, then it is used as a list of paths (normal path delimiting rules for
your system). These paths are merged. When a value is modified, it is modified in the file that defines the stanza. When
a value is created, it is created in the first file that exists. If no files in the chain exist, then it creates the
last file in the list.
3. Otherwise, ${HOME}/.kube/config is used and no merging takes place.
Available Commands:
current-context Display the current-context
delete-cluster 从 kubeconfig 中删除指定的集群
delete-context 从 kubeconfig 中删除指定的上下文
delete-user Delete the specified user from the kubeconfig
get-clusters 显示在 kubeconfig 中定义的集群
get-contexts 描述一个或多个上下文
get-users Display users defined in the kubeconfig
rename-context Rename a context from the kubeconfig file
set Set an individual value in a kubeconfig file
set-cluster Set a cluster entry in kubeconfig
set-context Set a context entry in kubeconfig
set-credentials Set a user entry in kubeconfig
unset Unset an individual value in a kubeconfig file
use-context Set the current-context in a kubeconfig file
view 显示合并的 kubeconfig 配置或一个指定的 kubeconfig 文件
Usage:
kubectl config SUBCOMMAND [options]
Use "kubectl <command> --help" for more information about a given command.
Use "kubectl options" for a list of global command-line options (applies to all commands).
k8s中支持yaml格式的文件应用，也支持json格式的应用，但还是yaml比较常用，因为json可读性太差。
人员名单:
张三:
年龄: 18 #
职业: Linux运维工程师
爱好:
- 看书
- 学习
- 加班
李四:
年龄: 20
职业: Java开发工程师 # 这是职业
爱好:
- 开源技术
- 微服务
- 分布式存储
大小写敏感
使用缩进表示层级关系
缩进时不允许使用Tal键，只允许使用空格
缩进的空格数目不重要，只要相同层级的元素左侧对齐即可
使用”#” 表示注释，从这个字符一直到行尾，都会被解析器忽略
比json更适用于配置文件
[root@k8s-harbor01 yaml]# cat nginx.yaml
apiVersion: apps/v1 # API版本，可以使用kubectl explain Deployment.apiVersion查看适用版本
kind: Deployment # 资源类型
metadata: # deployment控制器的元数据信息，kubectl explain Deployment.metadata
labels: # deployment控制器的标签，这个一般都是自定义的
app: myserver-nginx-deployment-label # 这就是自定义的标签（key和value都是自定义），后面会用到
name: myserver-nginx-deployment # deployment控制器的名称
namespace: myserver # deployment控制器所在的名称空间，不定义这个字段的话就在默认的名称空间defaule
spec: # 定义deployment中容器的详细信息
replicas: 1 # 定义deployment的副本数，也就是说可以创建多少个pod，不写默认值为1
selector: # 标签选择器（Deploy控制器会关联标签为app: myserver-nginx-selector的pod进行管理）
matchLabels: # 定义匹配的标签，必须要设置
app: myserver-nginx-selector # 匹配的目标标签
template: # 定义模板，必须定义，模板是起到描述要创建的pod的作用（pod创建就是根据模板内容来的）
metadata: # 定义模板元数据
labels: # 定义模板标签
app: myserver-nginx-selector # pod标签，该标签被上面的deploy控制器关联，并且svc也是关联这个标签进行访问的
spec: # 定义pod信息
containers: # 定义pod中的容器列表，可以多个，最少一个，pod不能动态增减容器
- name: myserver-nginx-container # 容器名称
image: 10.31.200.104/myserver/nginx:latest # 容器下载镜像的地址
imagePullPolicy: IfNotPresent # 镜像拉取策略: IfNotPresent，镜像不存在node节点就拉取。Always，不管镜像在不在，都拉取新的镜像。None，不拉取
ports: # 定义容器的端口列表（非必须配置，此处作用就算是声明）
- containerPort: 80 # 定义一个端口
protocol: TCP # 端口协议。注意：端口协议只支持：SCTP、TCP、UDP
name: http # 端口名称，不能重复
- containerPort: 443 # 定义一个端口
protocol: TCP # 端口协议
name: https # 端口名称
env: # 传递环境变量给容器，容器起来后就可以直接调用
- name: "password" # 变量名称，必须要用引号引起来
value: "123456" # 变量值
- name: "age"
value: "18"
resources: # 资源请求与限制
limits: # 资源限制设置，pod能使用的最大资源（上限）
cpu: 500m # cpu限制，单位为core（核）数，此处为500毫核，可以写0.5或者500m，1000m为1核。该配置不允许低于1m
memory: 2Gi # 内存限制，单位可以是Mib/Gib/M/B。
requests: # 资源请求设置（只有node节点上剩余资源满足cpu配置和memory配置，node节点才能被调度过去。）
# requests建议和limits配置成一样的，避免requests配置过低，容器启动过程中oom(简单点说就是能调度成功，但是容器启动实际需要1G内存，但是调度的时候只请求了512M，所以启动会oom)。
cpu: 200m # cpu请求数，容器启动的初始可用数量
memory: 512Mi # 内存请求大小，器启动的初始可用数量，用于调度pod时使用
[root@k8s-harbor01 yaml]# cat nginx-svc.yaml
kind: Service # 定义资源类型为service
apiVersion: v1 # svc 的API版本
metadata: # 定义svc的元数据
labels: # 定义svc的标签
app: myserver-nginx # 定义具体的标签名称
name: myserver-nginx-svc # 定义svc的名称，此名称会被core-dns解析
namespace: myserver # svc所处的ns，一定要和相关联的pod在同一个ns下
spec: # 定义svc的详细信息
type: NodePort # 定义svc的类型为NodePort，默认为Clusterip
ports: # 定义访问端口
- name: http # 定义一个端口名称
port: 80 # svc端口
protocol: TCP # 协议类型
targetPort: 80 # 目标pod端口
nodePort: 30001 # node节点暴露的端口.通过nodeport端口访问，会转发到targetPort:
- name: https # 定义一个端口名称
port: 443 # svc端口
protocol: TCP # 协议类型
targetPort: 443 # 目标pod端口
nodePort: 30443 # node节点暴露的端口
selector: # svc标签选择器，关联要访问的目标pod
app: myserver-nginx-selector # 将流量路由到标签关联的pod上
[root@k8s-harbor01 yaml]# kubectl apply -f nginx.yaml
deployment.apps/myserver-nginx-deployment created
[root@k8s-harbor01 yaml]# kubectl get po -n myserver
NAME READY STATUS RESTARTS AGE
myserver-nginx-deployment-5c9d79c56f-zcj7b 1/1 Running 0 10s
root@k8s-harbor01 yaml]# kubectl get po,svc -n myserver
NAME READY STATUS RESTARTS AGE
pod/myserver-nginx-deployment-5c9d79c56f-zcj7b 1/1 Running 0 61s
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
service/myserver-nginx-svc NodePort 10.100.140.203 <none> 80:30001/TCP,443:30443/TCP 8s
[root@k8s-harbor01 yaml]# kubectl get po,svc -n myserver
NAME READY STATUS RESTARTS AGE
pod/myserver-nginx-deployment-5c9d79c56f-zcj7b 1/1 Running 0 23m
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
service/myserver-nginx-svc NodePort 10.100.140.203 <none> 80:30001/TCP,443:30443/TCP 22m
[root@k8s-master01 ~]# curl -I 10.100.140.203
HTTP/1.1 200 OK
Server: nginx/1.23.4
Date: Thu, 04 May 2023 13:45:18 GMT
Content-Type: text/html
Content-Length: 615
Last-Modified: Tue, 28 Mar 2023 15:01:54 GMT
Connection: keep-alive
ETag: "64230162-267"
Accept-Ranges: bytes