k8s 常用工作负载控制器（Deployment、DaemonSet、Job、CronJob）
常用工作负载控制器
-
- 工作负载控制器是什么
- Deployment
-
- Deployment 使用流程
-
- Deployment 部署
- Deployment 升级
-
- 应用升级(更新镜像三种方式)
- 滚动升级
-
- 示例
- 水平扩缩容
- Deployment 回滚
- Deployment 下线
- Deployment ReplicaSet
- DaemonSet
- Job
- CronJob
- 遇到的报错
-
- 第一个问题
- 解决方法
工作负载控制器是什么
工作负载控制器(Workload Controllers）是K8s的一个抽象概念，用于更高级层次对象，部署和管理Pod
常用工作负载控制器
- Deployment ：无状态应用部署- StatefulSet :有状态应用部署
- DaemonSet ：确保所有Node运行同一个Pod
- Job :一次性任务
- Cronjob：定时任务
控制器的作用
- 管理Pod对象
- 使用标签与Pod关联
- 控制器实现了Pod的运维，例如滚动更新、伸缩、副本管理、维护Pod状态等。
Deployment
Deployment的功能
- 管理Pod和ReplicaSet
- 具有上线部署、副本设定、滚动升级、回滚等功能
- 提供声明式更新，例如只更新一个新的Image
应用场景
- 网站、API、微服务
Deployment 使用流程
Deployment 部署
部署镜像
方法1：kubectl apply -f xxx.yaml
方法2：kubectl create deployment web --image=ngin:
[root@master test]# cat deploy.yml
apiVersion: apps/v1
kind: Deployment
metadata:
name: test
namespace: default
spec:
replicas: 3
selector:
matchLabels:
app: b1
template:
metadata:
labels:
app: b1
spec:
containers:
- name: b1
image: busybox
imagePullPolicy: IfNotPresent
command: ["bin/sh","-c","sleep 9000"]
[root@master test]# kubectl apply -f deploy.yml
deployment.apps/test created
[root@master test]# kubectl get pod
NAME READY STATUS RESTARTS AGE
test-7964df7b4-bdbkx 1/1 Running 0 8s
test-7964df7b4-l67kj 1/1 Running 0 8s
test-7964df7b4-zwhhf 1/1 Running 0 8s
[root@master test]# kubectl get pod -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
test-7964df7b4-bdbkx 1/1 Running 0 50s 10.244.1.137 node1 <none> <none>
test-7964df7b4-l67kj 1/1 Running 0 50s 10.244.1.139 node1 <none> <none>
test-7964df7b4-zwhhf 1/1 Running 0 50s 10.244.1.138 node1 <none> <none>
Deployment 升级
应用升级(更新镜像三种方式)
kubectl apply -f xxx.yaml
kubectl set image deployment/web nginx=nginx
kubectl edit deployment/web #此方法不建议使用
[root@master test]# kubectl edit deployment/test
# Please edit the object below. Lines beginning with a '#' will be ignored,
# and an empty file will abort the edit. If an error occurs while saving this file will be
# reopened with the relevant failures.
#
apiVersion: apps/v1
kind: Deployment
metadata:
annotations:
deployment.kubernetes.io/revision: "1"
kubectl.kubernetes.io/last-applied-configuration: |
creationTimestamp: "2021-12-24T13:41:04Z"
generation: 1
name: test
namespace: default
resourceVersion: "157409"
uid: 0742158a-a570-4dfa-b6ba-561b806b69f7
spec:
progressDeadlineSeconds: 600
replicas: 3
revisionHistoryLimit: 10
selector:
matchLabels:
app: b1
strategy:
rollingUpdate:
maxSurge: 25%
maxUnavailable: 25%
type: RollingUpdate
template:
metadata:
creationTimestamp: null
labels:
app: b1
spec:
containers:
- command:
- bin/sh
- -c
- sleep 9000
image: busybox
imagePullPolicy: IfNotPresent
name: b1
resources: {}
terminationMessagePath: /dev/termination-log
terminationMessagePolicy: File
dnsPolicy: ClusterFirst
restartPolicy: Always
schedulerName: default-scheduler
securityContext: {}
terminationGracePeriodSeconds: 30
status:
availableReplicas: 3
conditions:
- lastTransitionTime: "2021-12-24T13:41:06Z"
lastUpdateTime: "2021-12-24T13:41:06Z"
message: Deployment has minimum availability.
reason: MinimumReplicasAvailable
status: "True"
type: Available
- lastTransitionTime: "2021-12-24T13:41:04Z"
lastUpdateTime: "2021-12-24T13:41:06Z"
message: ReplicaSet "test-7964df7b4" has successfully progressed.
reason: NewReplicaSetAvailable
status: "True"
type: Progressing
observedGeneration: 1
readyReplicas: 3
replicas: 3
updatedReplicas: 3
滚动升级
K8s对寸Pod升级的默认策略，通过使用新版本Pod逐步更新旧版本Pod，实现零停机发布，用户无感知。
滚动升级在K8s中的实现
- 1个Deployment.
- 2个ReplicaSet
滚动更新策略
- maxSurge：
滚动更新过程中最大Pod副本数，确保在更新时启动的Pod数量比期望（replicas)Pod数量最大多出25% - maxUnavailable：
滚动更新过程中最大不可用Pod副本数，确保在更新时最大25% Pod数量不可用，即确保75% Pod数量是可用状态 有四舍五入的功能，是根据副本数量而决定的
示例
[root@master test]# cat test.yml
apiVersion: apps/v1
kind: Deployment
metadata:
name: web
namespace: default
spec:
replicas: 3
selector:
matchLabels:
app: web
template:
metadata:
labels:
app: web
spec:
containers:
- name: web
image: 1314444/httpd:v0.1
imagePullPolicy: IfNotPresent
[root@master test]# kubectl apply -f test.yml
deployment.apps/web created
[root@master test]# kubectl get pod
NAME READY STATUS RESTARTS AGE
web-c45fdccd9-shmdj 1/1 Running 0 2m1s
web-c45fdccd9-xthqz 1/1 Running 0 2m1s
web-c45fdccd9-ztzk7 1/1 Running 0 2m1s
//更新
[root@master test]# cat test.yml
apiVersion: apps/v1
kind: Deployment
metadata:
name: web
namespace: default
spec:
replicas: 4
strategy:
rollingUpdate:
maxSurge: 25% #默认便是25%，所以可以不用写
maxUnavailable: 25% #默认便是25%，所以可以不用写
type: RollingUpdate
selector:
matchLabels:
app: web
template:
metadata:
labels:
app: web
spec:
containers:
- name: web
image: 1314444/httpd:v0.2
imagePullPolicy: IfNotPresent
[root@master test]# kubectl apply -f test.yml
deployment.apps/web configured
[root@master test]# kubectl get pod
NAME READY STATUS RESTARTS AGE
web-c45fdccd9-bjt6r 1/1 Running 0 2s
web-c45fdccd9-shmdj 1/1 Running 0 3m
web-c45fdccd9-xthqz 1/1 Running 0 3m
web-c45fdccd9-ztzk7 1/1 Running 0 3m
rollingUpdate 有四舍五入的功能，是根据副本数量而决定
-------双数副本数量-------
[root@master test]# cat test.yml
apiVersion: apps/v1
kind: Deployment
metadata:
name: web
namespace: default
spec:
replicas: 4
strategy:
rollingUpdate:
maxSurge: 50%
maxUnavailable: 50%
type: RollingUpdate
selector:
matchLabels:
app: web
template:
metadata:
labels:
app: web
spec:
containers:
- name: web
image: 1314444/httpd:v0.1
imagePullPolicy: IfNotPresent
[root@master test]# kubectl apply -f test.yml
deployment.apps/web configured
[root@master test]# kubectl get pod
NAME READY STATUS RESTARTS AGE
web-865bffff44-ft6xg 1/1 Running 0 3s
web-865bffff44-gdjdj 1/1 Running 0 3s
web-865bffff44-rgwv6 1/1 Running 0 3s
web-865bffff44-whdhh 1/1 Running 0 3s
web-c45fdccd9-bjt6r 1/1 Terminating 0 9m11s
web-c45fdccd9-shmdj 1/1 Terminating 0 12m
web-c45fdccd9-xthqz 1/1 Terminating 0 12m
web-c45fdccd9-ztzk7 1/1 Terminating 0 12m
-------副本数量单数-------
[root@master test]# cat test.yml
apiVersion: apps/v1
kind: Deployment
metadata:
name: web
namespace: default
spec:
replicas: 5
strategy:
rollingUpdate:
maxSurge: 50%
maxUnavailable: 50%
type: RollingUpdate
selector:
matchLabels:
app: web
template:
metadata:
labels:
app: web
spec:
containers:
- name: web
image: 1314444/httpd:v0.2
imagePullPolicy: IfNotPresent
[root@master test]# kubectl apply -f test.yml
deployment.apps/web configured
[root@master test]# kubectl get pod
NAME READY STATUS RESTARTS AGE
web-865bffff44-ft6xg 1/1 Terminating 0 4m4s
web-865bffff44-gdjdj 1/1 Terminating 0 4m4s
web-865bffff44-nqskm 0/1 Terminating 0 2s
web-865bffff44-rgwv6 1/1 Terminating 0 4m4s
web-865bffff44-whdhh 1/1 Running 0 4m4s
web-c45fdccd9-6s8vr 1/1 Running 0 2s
web-c45fdccd9-jgcgm 0/1 ContainerCreating 0 2s
web-c45fdccd9-qmw2k 0/1 ContainerCreating 0 2s
web-c45fdccd9-wdnvj 0/1 ContainerCreating 0 2s
web-c45fdccd9-zf4mt 1/1 Running 0 2s
-------四舍五入-------
[root@master test]# cat test.yml
apiVersion: apps/v1
kind: Deployment
metadata:
name: web
namespace: default
spec:
replicas: 5
strategy:
rollingUpdate:
maxSurge: 49%
maxUnavailable: 49%
type: RollingUpdate
selector:
matchLabels:
app: web
template:
metadata:
labels:
app: web
spec:
containers:
- name: web
image: 1314444/httpd:v0.1
imagePullPolicy: IfNotPresent
[root@master test]# kubectl apply -f test.yml
deployment.apps/web configured
[root@master test]# kubectl get pod
NAME READY STATUS RESTARTS AGE
web-865bffff44-89grr 1/1 Running 0 1s
web-865bffff44-d2ggx 0/1 ContainerCreating 0 1s
web-865bffff44-fzg6s 1/1 Running 0 1s
web-865bffff44-sv27k 1/1 Running 0 1s
web-865bffff44-w2jdq 1/1 Running 0 1s
web-c45fdccd9-6s8vr 1/1 Terminating 0 5m20s
web-c45fdccd9-jgcgm 1/1 Terminating 0 5m20s
web-c45fdccd9-qmw2k 1/1 Terminating 0 5m20s
web-c45fdccd9-wdnvj 1/1 Terminating 0 5m20s
web-c45fdccd9-zf4mt 1/1 Terminating 0 5m20s
水平扩缩容
水平扩缩容(启动多实例,提高并发)
- 修改yaml里replicas值，再apply
- kubectl scale deployment web --replicas=10
注: replicas参数控制Pod副本数量
[root@master test]# cat test.yml
apiVersion: apps/v1
kind: Deployment
metadata:
name: web
namespace: default
spec:
replicas: 3 #副本数量
strategy:
rollingUpdate:
maxSurge: 49%
maxUnavailable: 49%
type: RollingUpdate
selector:
matchLabels:
app: web
template:
metadata:
labels:
app: web
spec:
containers:
- name: web
image: 1314444/httpd:v0.2
imagePullPolicy: IfNotPresent
[root@master test]# kubectl apply -f test.yml
deployment.apps/web configured
[root@master test]# kubectl get pod
NAME READY STATUS RESTARTS AGE
web-865bffff44-89grr 1/1 Terminating 0 8m35s
web-865bffff44-d2ggx 1/1 Terminating 0 8m35s
web-865bffff44-fzg6s 1/1 Running 0 8m35s
web-865bffff44-sv27k 1/1 Running 0 8m35s
web-865bffff44-w2jdq 1/1 Running 0 8m35s
Deployment 回滚
回滚（发布失败恢复正常版本)
kubectl rollout history deployment/web #查看历史发布版本
kubectl rollout undo deployment/web #回滚上一个版本
kubectl rollout undo deployment/web --to-revision=2 #回滚历史指定版本
注:回滚是重新部署某一次部署时的状态，即当时版本所有配置
//查看历史发布版本
[root@master test]# kubectl rollout history deploy/web
deployment.apps/web
REVISION CHANGE-CAUSE
3 <none>
4 <none>
//回滚上一个版本
[root@master test]# cat test.yml
apiVersion: apps/v1
kind: Deployment
metadata:
name: web
namespace: default
spec:
replicas: 3
strategy:
rollingUpdate:
maxSurge: 49%
maxUnavailable: 49%
type: RollingUpdate
selector:
matchLabels:
app: web
template:
metadata:
labels:
app: web
spec:
containers:
- name: web
image: 1314444/httpd:v0.1
imagePullPolicy: IfNotPresent
[root@master test]# kubectl apply -f test.yml
deployment.apps/web configured
[root@master test]# kubectl get pod -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
web-865bffff44-hpqw9 1/1 Running 0 67s 10.244.1.173 node1 <none> <none>
web-865bffff44-nwbx4 1/1 Running 0 67s 10.244.1.174 node1 <none> <none>
web-865bffff44-w9568 1/1 Running 0 67s 10.244.1.172 node1 <none> <none>
[root@master test]# curl 10.244.1.174
test page on jjyy
[root@master test]# kubectl rollout undo deploy/web
deployment.apps/web rolled back
[root@master test]# kubectl get pod -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
web-865bffff44-hpqw9 1/1 Terminating 0 67s 10.244.1.173 node1 <none> <none>
web-865bffff44-nwbx4 1/1 Terminating 0 67s 10.244.1.174 node1 <none> <none>
web-865bffff44-w9568 1/1 Terminating 0 67s 10.244.1.172 node1 <none> <none>
web-c45fdccd9-8cm86 1/1 Running 0 8s 10.244.1.175 node1 <none> <none>
web-c45fdccd9-bhndv 1/1 Running 0 8s 10.244.1.176 node1 <none> <none>
web-c45fdccd9-k8c7b 1/1 Running 0 8s 10.244.1.177 node1 <none> <none>
[root@master test]# curl 10.244.1.174
test page on jjyy
[root@master test]# curl 10.244.1.177
test page on 666
Deployment 下线
- kubectl delete deploy/web
- kubectl delete svc/web
//删除(推荐使用)
[root@master test]# kubectl delete -f test.yml
deployment.apps "web" deleted
[root@master test]# kubectl get pod
NAME READY STATUS RESTARTS AGE
web-865bffff44-9sbnl 1/1 Terminating 0 5m26s
web-865bffff44-b44nb 1/1 Terminating 0 5m26s
web-865bffff44-tvzvw 1/1 Terminating 0 5m26s
Deployment ReplicaSet
ReplicaSet控制器用途
- Pod副本数量管理，不断对比当前Pod数量与期望Pod数量
- Deployment每次发布都会创建一个RS作为记录，用于实现回滚
- 默认为一个Pod数量
[root@master test]# kubectl get pod
NAME READY STATUS RESTARTS AGE
web-865bffff44-49zns 1/1 Running 0 42s
web-865bffff44-7g7b5 1/1 Running 0 42s
web-865bffff44-rq59f 1/1 Running 0 42s
[root@master test]# kubectl get rs #查看RS记录（根据副本的多少来判断）
NAME DESIRED CURRENT READY AGE
web-865bffff44 3 3 3 3s
[root@master test]# kubectl rollout history deploy web #版本对应RS记录
deployment.apps/web
REVISION CHANGE-CAUSE
1 <none>
DaemonSet
DaemonSet功能
- 在每一个Node上运行一个Pod
- 新加入的Node也同样会自动运行一个Pod
应用场景
- 网络插件(kube-proxy、calico)、其他Agent
示例:部署一个日志采集程序
[root@master test]# cat daemon.yml
apiVersion: apps/v1
kind: DaemonSet
metadata:
name: filebeat
namespace: kube-system
spec:
selector:
matchLabels:
app: filebeat
template:
metadata:
labels:
app: filebeat
spec:
containers:
- name: log
image: elastic/filebeat:7.16.2
imagePullPolicy: IfNotPresent
[root@master test]# kubectl apply -f daemon.yml
daemonset.apps/filebeat created
[root@master test]# kubectl get pod -n kube-system
NAME READY STATUS RESTARTS AGE
coredns-7f89b7bc75-ptq5m 1/1 Running 14 6d7h
coredns-7f89b7bc75-v6chh 1/1 Running 14 6d7h
etcd-master 1/1 Running 16 6d7h
filebeat-4l848 0/1 ContainerCreating 0 8s #首次拉取镜像有点慢
filebeat-wk9dt 0/1 ContainerCreating 0 8s
kube-apiserver-master 1/1 Running 16 6d7h
kube-controller-manager-master 1/1 Running 16 6d7h
kube-flannel-ds-cchk6 1/1 Running 12 6d6h
kube-flannel-ds-d2wpq 1/1 Running 14 6d6h
kube-flannel-ds-z6f85 1/1 Running 0 160m
kube-proxy-6f99q 1/1 Running 13 6d7h
kube-proxy-9z78l 1/1 Running 11 6d7h
kube-proxy-gz4bs 1/1 Running 16 6d7h
kube-scheduler-master 1/1 Running 16 6d7h
//DaemonSet类型的会在除了master节点以外的所有节点上创建
[root@master test]# kubectl get pod -n kube-system -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
coredns-7f89b7bc75-ptq5m 1/1 Running 14 6d7h 10.244.0.38 master <none> <none>
coredns-7f89b7bc75-v6chh 1/1 Running 14 6d7h 10.244.0.39 master <none> <none>
etcd-master 1/1 Running 16 6d7h 192.168.129.250 master <none> <none>
filebeat-4l848 1/1 Running 0 3m5s 10.244.2.59 node2 <none> <none>
filebeat-wk9dt 1/1 Running 0 3m5s 10.244.1.183 node1 <none> <none>
kube-apiserver-master 1/1 Running 16 6d7h 192.168.129.250 master <none> <none>
kube-controller-manager-master 1/1 Running 16 6d7h 192.168.129.250 master <none> <none>
kube-flannel-ds-cchk6 1/1 Running 12 6d6h 192.168.129.136 node2 <none> <none>
kube-flannel-ds-d2wpq 1/1 Running 14 6d6h 192.168.129.250 master <none> <none>
kube-flannel-ds-z6f85 1/1 Running 0 163m 192.168.129.135 node1 <none> <none>
kube-proxy-6f99q 1/1 Running 13 6d7h 192.168.129.136 node2 <none> <none>
kube-proxy-9z78l 1/1 Running 11 6d7h 192.168.129.135 node1 <none> <none>
kube-proxy-gz4bs 1/1 Running 16 6d7h 192.168.129.250 master <none> <none>
kube-scheduler-master 1/1 Running 16 6d7h 192.168.129.250 master <none> <none>
加入新节点
//查看本地节点
[root@master ~]# kubectl get node
NAME STATUS ROLES AGE VERSION
master Ready control-plane,master 6d22h v1.20.0
node1 Ready <none> 6d22h v1.20.0
node2 Ready <none> 6d22h v1.20.0
//加入新的节点
//注释swap分区
[root@master ~]# sed -i.bak '/swap/s/^/#/' /etc/fstab
//关闭防火墙
[root@node3 ~]# systemctl disable --now firewalld
Removed symlink /etc/systemd/system/multi-user.target.wants/firewalld.service.
Removed symlink /etc/systemd/system/dbus-org.fedoraproject.FirewallD1.service.
[root@node3 ~]# sed -i 's/enforcing/disabled/' /etc/selinux/config
//重启
[root@node3 ~]# reboot
//配置yum源
[root@node3 ~]# curl -o /etc/yum.repos.d/CentOS-Base.repo https://mirrors.aliyun.com/repo/Centos-8.repo
[root@node3 ~]# sed -i -e '/mirrors.cloud.aliyuncs.com/d' -e '/mirrors.aliyuncs.com/d' /etc/yum.repos.d/CentOS-Base.repo
[root@node3 ~]# yum clean all && yum makecache
//时间同步
[root@node3 ~]# yum -y install chrony
[root@node3 ~]# sed -i 's/2.centos.pool.ntp.org/time1.aliyun.com/' /etc/chrony.conf
[root@node3 ~]# systemctl enable --now chronyd
[root@node3 ~]# date
2021年 12月 25日 星期六 14:51:13 CST
//安装Docker
[root@node3 ~]# yum -y install wget
[root@node3 ~]# wget https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo -O /etc/yum.repos.d/docker-ce.repo
[root@node3 ~]# yum -y install docker-ce
[root@node3 ~]# systemctl enable --now docker
Created symlink /etc/systemd/system/multi-user.target.wants/docker.service → /usr/lib/systemd/system/docker.service.
[root@node3 ~]# docker --version
Docker version 20.10.12, build e91ed57
[root@master ~]# ls /etc/docker/
key.json
//镜像加速
[root@master ~]# cat > /etc/docker/daemon.json << EOF
{
"registry-mirrors": ["https://b9pmyelo.mirror.aliyuncs.com"],
"exec-opts": ["native.cgroupdriver=systemd"],
"log-driver": "json-file",
"log-opts": {
"max-size": "100m"
},
"storage-driver": "overlay2"
}
EOF
//添加kubernetes阿里云YUM软件源
[root@node3 ~]# cat > /etc/yum.repos.d/kubernetes.repo << EOF
[kubernetes]
name=Kubernetes
baseurl=https://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64
enabled=1
gpgcheck=0
repo_gpgcheck=0
gpgkey=https://mirrors.aliyun.com/kubernetes/yum/doc/yum-key.gpg https://mirrors.aliyun.com/kubernetes/yum/doc/rpm-package-key.gpg
EOF
[root@node3 ~]# yum clean all && yum makecache
//安装kubeadm，kubelet和kubectl,由于版本更新频繁，这里指定版本号部署
[root@node3 ~]# yum install -y kubelet-1.20.0 kubeadm-1.20.0 kubectl-1.20.0
[root@node3 ~]# systemctl enable kubelet
Created symlink /etc/systemd/system/multi-user.target.wants/kubelet.service → /usr/lib/systemd/system/kubelet.service.
[root@node3 ~]# systemctl status kubelet
● kubelet.service - kubelet: The Kubernetes Node Agent
Loaded: loaded (/usr/lib/systemd/system/kubelet.service; enabled; vendor preset: disabled)
Drop-In: /usr/lib/systemd/system/kubelet.service.d
└─10-kubeadm.conf
Active: inactive (dead)
//master端做域名解析
[root@master ~]# cat /etc/hosts
127.0.0.1 localhost localhost.localdomain localhost4 localhost4.localdomain4
::1 localhost localhost.localdomain localhost6 localhost6.localdomain6
192.168.129.250 master master.example.com
192.168.129.135 node1 node1.example.com
192.168.129.136 node2 node2.example.com
192.168.129.205 node3 node3.example.com
//做免密登录
[root@master ~]# ssh-copy-id node3
//加入集群
//此时需要通过 kubedam重新生成token
[root@master ~]# token=$(kubeadm token generate)
[root@master ~]# kubeadm token create $token --print-join-command --ttl=0
kubeadm join 192.168.129.250:6443 --token k1m9je.bh5l7nddlw548eva --discovery-token-ca-cert-hash sha256:f6be891c6cd273a9283a6c05ca795811f7350afa2b5072990a294b7070ff9a4f
[root@node3 ~]# kubeadm join 192.168.129.250:6443 --token k1m9je.bh5l7nddlw548eva --discovery-token-ca-cert-hash sha256:f6be891c6cd273a9283a6c05ca795811f7350afa2b5072990a294b7070ff9a4f
[preflight] Running pre-flight checks
[WARNING FileExisting-tc]: tc not found in system path
[WARNING SystemVerification]: this Docker version is not on the list of validated versions: 20.10.12. Latest validated version: 19.03
[WARNING Hostname]: hostname "node3" could not be reached
[WARNING Hostname]: hostname "node3": lookup node3 on 114.114.114.114:53: no such host
[preflight] Reading configuration from the cluster...
[preflight] FYI: You can look at this config file with 'kubectl -n kube-system get cm kubeadm-config -o yaml'
[kubelet-start] Writing kubelet configuration to file "/var/lib/kubelet/config.yaml"
[kubelet-start] Writing kubelet environment file with flags to file "/var/lib/kubelet/kubeadm-flags.env"
[kubelet-start] Starting the kubelet
[kubelet-start] Waiting for the kubelet to perform the TLS Bootstrap...
This node has joined the cluster:
* Certificate signing request was sent to apiserver and a response was received.
* The Kubelet was informed of the new secure connection details.
Run 'kubectl get nodes' on the control-plane to see this node join the cluster.
[root@master ~]# kubectl get node
NAME STATUS ROLES AGE VERSION
master Ready control-plane,master 7d v1.20.0
node1 Ready <none> 7d v1.20.0
node2 Ready <none> 7d v1.20.0
node3 Ready <none> 57s v1.20.0
//会在新加入的节点上创建
[root@master ~]# kubectl get pod -n kube-system -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
coredns-7f89b7bc75-4qsdc 1/1 Running 0 41m 10.244.1.218 node1 <none> <none>
coredns-7f89b7bc75-zx59r 1/1 Running 0 41m 10.244.1.219 node1 <none> <none>
etcd-master 1/1 Running 17 7d 192.168.129.250 master <none> <none>
filebeat-97ch5 1/1 Running 0 140m 10.244.1.217 node1 <none> <none>
filebeat-nk4jb 1/1 Running 0 54s 10.244.4.2 node3 <none> <none>
filebeat-qbmjk 1/1 Running 0 140m 10.244.2.60 node2 <none> <none>
kube-apiserver-master 1/1 Running 17 7d 192.168.129.250 master <none> <none>
//删除DaemonSet
[root@master ~]# kubectl delete daemonset/filebeat -n kube-system
Job
Job分为普通任务(Job）和定时任务(CronJob)：一次性执行
应用场景：离线数据处理，视频解码等业务
[root@master test]# cat job.yml
apiVersion: batch/v1
kind: Job
metadata:
name: b1
spec:
template:
spec:
containers:
- name: b1
image: busybox
imagePullPolicy: IfNotPresent
command: [" /bin/sh" , "-c" , "echo hello world"]
restartPolicy: Never
backoffLimit: 2 #重启次数
[root@master test]# kubectl apply -f job.yml
job.batch/b1 created
[root@master test]# kubectl get pod
NAME READY STATUS RESTARTS AGE
b1-hw5ls 0/1 ContainerCannotRun 0 2s
b1-v7th8 0/1 ContainerCreating 0 1s
[root@master test]# kubectl describe job/b1
Name: b1
Namespace: default
Selector: controller-uid=8850b237-a360-405e-87e8-f5c83254e741
Labels: controller-uid=8850b237-a360-405e-87e8-f5c83254e741
job-name=b1
Annotations: <none>
Parallelism: 1
Completions: 1
Start Time: Fri, 24 Dec 2021 23:51:13 +0800
Pods Statuses: 1 Running / 0 Succeeded / 1 Failed
Pod Template:
Labels: controller-uid=8850b237-a360-405e-87e8-f5c83254e741
job-name=b1
Containers:
b1:
Image: busybox
Port: <none>
Host Port: <none>
Command:
/bin/sh
-c
echo hello world
Environment: <none>
Mounts: <none>
Volumes: <none>
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal SuccessfulCreate 6s job-controller Created pod: b1-hw5ls
Normal SuccessfulCreate 5s job-controller Created pod: b1-v7th8
CronJob
CronJob用于实现定时任务，像Linux的Crontab一样：定时任务
应用场景：通知，备份
[root@master test]# cat cronjob.yml
apiVersion: batch/v1beta1
kind: CronJob
metadata:
name: hello
spec:
schedule: "*/1 * * * *"
jobTemplate:
spec:
template:
spec:
containers:
- name: hello
image: busybox
imagePullPolicy: IfNotPresent
command:
- /bin/sh
- "-c"
- "date;echo Hello world"
restartPolicy: OnFailure
[root@master test]# kubectl apply -f cronjob.yml
cronjob.batch/hello created
[root@master test]# kubectl get pod
NAME READY STATUS RESTARTS AGE
hello-1640362320-cvdhv 0/1 Completed 0 60s
[root@master test]# kubectl get pod #每隔一分钟
NAME READY STATUS RESTARTS AGE
hello-1640362320-cvdhv 0/1 Completed 0 60s
hello-1640362380-vpbs5 0/1 ContainerCreating 0 0s
遇到的报错
（将新的节点加入集群时遇到的）
第一个问题
[root@node3 ~]# kubeadm join 192.168.129.250:6443 --token hglo7o.0ya3tbi82wqdjif4 \
--discovery-token-ca-cert-hash sha256:f6be891c6cd273a9283a6c05ca795811f7350afa2b5072990a294b7070ff9a4f
[preflight] Running pre-flight checks
[WARNING FileExisting-tc]: tc not found in system path
[WARNING SystemVerification]: this Docker version is not on the list of validated versions: 20.10.12. Latest validated version: 19.03
[WARNING Hostname]: hostname "node3" could not be reached
[WARNING Hostname]: hostname "node3": lookup node3 on 192.168.129.2:53: no such host
[kubelet-check] The HTTP call equal to 'curl -sSL http://localhost:10248/healthz' failed with error: Get "http://localhost:10248/healthz": dial tcp [::1]:10248: connect: connection refused.
error execution phase kubelet-start: error uploading crisocket: timed out waiting for the condition
To see the stack trace of this error execute with --v=5 or higher
解决方法
token 过期
此时需要通过kubedam重新生成token
//生成新的token
[root@master ~]# kubeadm token list
[root@master ~]# token=$(kubeadm token generate)
//创建永不过期的token
[root@master ~]# kubeadm token create $token --print-join-command --ttl=0
kubeadm join 192.168.129.250:6443 --token q8gddz.5ihmiuop488jvjvu --discovery-token-ca-cert-hash sha256:f6be891c6cd273a9283a6c05ca795811f7350afa2b5072990a294b7070ff9a4f