文章目錄
- 一：控制器的類型
- 一： pod與控制器之間的關係
- 二：deployment
- 三：statefulset
- 3.1 deployment和statefulset區別
- 3.2 常規service和無頭服務的區別
- 3.3 先創建之前deployment控制器pod的常規服務
- 3.3 在node節點去測試集羣內部通訊
- 3.4 創建headless無頭服務
- 3.5 查看服務，出現一個沒有cluster-ip的服務
- 3.6 開始做dns服務
- 3.7 創建dns的服務
- 3.8 查看創建後的狀態
- 3.9 創建一個測試pod資源
- 3.10 驗證dns解析
- 3.11 解析kubernetes和nginx-service名稱
- 3.12 nodes節點重啓一下flanneld組件和docker
- 3.13 創建statefulset 資源
- 3.14 創建前先清理下之前的環境
- 3.15 創建測試dns容器
- 3.16 查看網絡
- 3.17 總結
- 更新 StatefulSet
- 四：daemonset
- 五：job
故障排查
| 狀態值 | 描述 |
|---|---|
| pending | pod創建已經提交到kubernetes；但是，因爲某些原因而不能順利創建——例如下載鏡像慢、調度不成功 |
| running | pod已經綁定到一個節點，並且已經創建了所有容器；至少有一個容器正在運行中，或正在啓動或重新啓動 |
| succeeded/competed | pod中的所有容器都已成功終止，不會重新啓動 |
| failed | pod的所有容器均已終止，且至少有一個容器已在故障中終止；也就是說，容器要麼以非零狀態退出，要麼被系統終止 |
| unknown | 由於某種原因apiserver無法獲得pod的狀態，通常是由於master與pod所在主機kubelet通信時出錯 |
解決思路：
- 查看pod事件
kubectl describe type name_prefix
- 查看pod日誌(failed狀態下重點看)
kubectl logs pod_name
- 進入pod（狀態爲running，但是服務沒有提供的情況下）
kubectl exec -it pod_name bash
一：控制器的類型
控制器：又稱爲工作負載，分別包含以下類型控制器
1.deployment 無狀態化部署控制器
2.statefulset 有狀態化部署
3.daemonset 一次部署，所有的節點都會部署
4.job 一次性任務
5.cronjob 週期性任務
一： pod與控制器之間的關係
controllers：在集羣上管理和運行容器的對象，通過labels-selector相關聯
pod通過控制器實現應用的運維，比如伸縮，升級等
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二：deployment
部署無狀態應用
應用場景：web服務,比如tomcat
2.1 deployment概述
- deployment管理pod和replicaset
- 具有上線部署、副本設定、滾動升級回滾等功能
- 提供聲明式更新，例如只更新一個新的image
2.1 演示
2.1.1 編寫yaml文件
[root@master1 gsy]# vim nginx-deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
name: nginx-deployment
labels:
app: nginx
spec:
replicas: 3
selector:
matchLabels:
app: nginx
template:
metadata:
labels:
app: nginx
spec:
containers:
- name: nginx1
image: nginx:1.15.4
ports:
- containerPort: 80
2.1.2 創建pod
[root@master1 gsy]# kubectl create -f nginx-deployment.yaml
deployment.apps/nginx-deployment created
[root@master1 gsy]# kubectl get pods -w
NAME READY STATUS RESTARTS AGE
nginx-deployment-78cdb5b557-c2cwv 1/1 Running 0 29s
nginx-deployment-78cdb5b557-d6wlp 1/1 Running 0 29s
nginx-deployment-78cdb5b557-lt52n 1/1 Running 0 29s
pod9 1/1 Running 0 41h
^C[root@master1 gsy]# kubectl get all
NAME READY STATUS RESTARTS AGE
pod/nginx-deployment-78cdb5b557-c2cwv 1/1 Running 0 14m
pod/nginx-deployment-78cdb5b557-d6wlp 1/1 Running 0 14m
pod/nginx-deployment-78cdb5b557-lt52n 1/1 Running 0 14m
pod/pod9 1/1 Running 0 42h
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
service/kubernetes ClusterIP 10.0.0.1 <none> 443/TCP 14d
NAME DESIRED CURRENT UP-TO-DATE AVAILABLE AGE
deployment.apps/nginx-deployment 3 3 3 3 14m
NAME DESIRED CURRENT READY AGE
replicaset.apps/nginx-deployment-78cdb5b557 3 3 3 14m
2.1.3 查看控制器參數
參數有兩種查看，一種是describe，還有一種是edit編輯的方式
通常來說，edit會更詳細一點
[root@master1 gsy]# kubectl describe deploy nginx-deployment
Name: nginx-deployment
Namespace: default
CreationTimestamp: Fri, 15 May 2020 08:42:18 +0800
Labels: app=nginx
Annotations: deployment.kubernetes.io/revision: 1
Selector: app=nginx
Replicas: 3 desired | 3 updated | 3 total | 3 available | 0 unavailable
StrategyType: RollingUpdate
MinReadySeconds: 0
RollingUpdateStrategy: 25% max unavailable, 25% max surge
Pod Template:
Labels: app=nginx
Containers:
nginx1:
Image: nginx:1.15.4
Port: 80/TCP
Host Port: 0/TCP
Environment: <none>
Mounts: <none>
Volumes: <none>
Conditions:
Type Status Reason
---- ------ ------
Available True MinimumReplicasAvailable
Progressing True NewReplicaSetAvailable
OldReplicaSets: <none>
NewReplicaSet: nginx-deployment-78cdb5b557 (3/3 replicas created)
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal ScalingReplicaSet 17m deployment-controller Scaled up replica set nginx-deployment-78cdb5b557 to 3
[root@master1 gsy]# kubectl edit deploy nginx-deployment
# 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: extensions/v1beta1
kind: Deployment
metadata:
annotations:
deployment.kubernetes.io/revision: "1"
creationTimestamp: 2020-05-15T00:42:18Z
generation: 1
labels:
app: nginx
name: nginx-deployment
namespace: default
resourceVersion: "897701"
selfLink: /apis/extensions/v1beta1/namespaces/default/deployments/nginx-deployment
uid: ee238868-9644-11ea-a668-000c29db840b
'spec:
progressDeadlineSeconds: 600
replicas: 3
revisionHistoryLimit: 10
selector:
matchLabels: #匹配標籤
app: nginx
strategy:
rollingUpdate:
maxSurge: 25%
maxUnavailable: 25%
type: RollingUpdate'
template:
metadata:
creationTimestamp: null
labels:
app: nginx
' spec:
containers:
- image: nginx:1.15.4
imagePullPolicy: IfNotPresent
name: nginx1
ports:
- containerPort: 80
protocol: TCP
resources: {}
terminationMessagePath: /dev/termination-log
terminationMessagePolicy: File
dnsPolicy: ClusterFirst
restartPolicy: Always
schedulerName: default-scheduler
securityContext: {}
terminationGracePeriodSeconds: 30
status:
availableReplicas: 3
conditions:
- lastTransitionTime: 2020-05-15T00:42:30Z
lastUpdateTime: 2020-05-15T00:42:30Z
message: Deployment has minimum availability.
reason: MinimumReplicasAvailable
status: "True"
type: Available
- lastTransitionTime: 2020-05-15T00:42:18Z
lastUpdateTime: 2020-05-15T00:42:30Z
message: ReplicaSet "nginx-deployment-78cdb5b557" has successfully progressed.
reason: NewReplicaSetAvailable
status: "True"
type: Progressing
observedGeneration: 1
readyReplicas: 3
replicas: 3
updatedReplicas: 3
滾動更新機制：先創建新資源，再關閉舊資源，一個一個替換
strategy:
rollingUpdate:
maxSurge: 25%
maxUnavailable: 25%
type: RollingUpdate'
matchlabels：匹配標籤
maxsurge 最多擴容容量是百分之25
maxunavailable 最大縮減的數量不能超過25
2.1.4 查看控制器歷史版本
回滾機制就是依此執行
[root@master1 gsy]# kubectl rollout history deployment/nginx-deployment
deployment.extensions/nginx-deployment
REVISION CHANGE-CAUSE
1 <none>
三：statefulset
部署有狀態應用
解決pod獨立生命週期，保持pod啓動順序和唯一性
穩定，唯一的網絡標識符，持久存儲（例如：etcd配置文件，節點地址會發生變化，將無法正常使用）
有序部署，可以穩定的部署、擴展、刪除和終止（例如：mysql主從關係，先啓動主，在啓動從）
有序，滾動更新
應用場景：數據庫等獨立性服務
官方文檔：https://kubernetes.io/docs/concepts/workloads/controllers/statefulset/
3.1 deployment和statefulset區別
- 無狀態
1.deployment控制器認爲所有的pod都是一樣的
2.不考慮pod開啓順序的要求
3.不考慮在哪個node節點上運行
4.可以隨意擴容和縮容
- 有狀態
1.實例之間有差別，每個實例都有自己的獨特性，元數據不同，例如：etcd、zookeeper
zookeeper微服務用的多
2.實例之間不對等的關係，以及依靠外部存儲的應用
3.2 常規service和無頭服務的區別
常規service：是一組pod的訪問策略，提供cluester-ip羣集之間通訊，還提供負載均衡和服務發現
無頭服務headless service：無頭服務，不需要cluster-ip，直接綁定具體的pod的IP
無頭服務通常用於statefulset有狀態部署
3.3 先創建之前deployment控制器pod的常規服務
[root@master1 gsy]# vim nginx-service.yaml
apiVersion: v1
kind: Service
metadata:
name: nginx-service
labels:
app: nginx
spec:
type: NodePort
ports:
- port: 80
targetPort: 80
selector:
app: nginx
cluster-IP實現內部羣集通信地址
[root@master1 gsy]# kubectl create -f nginx-service.yaml
service/nginx-service created
[root@master1 gsy]# kubectl get service
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kubernetes ClusterIP 10.0.0.1 <none> 443/TCP 14d
nginx-service NodePort 10.0.0.31 <none> 80:37384/TCP 11s
3.3 在node節點去測試集羣內部通訊
[root@node01 ~]# curl 10.0.0.31
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>
body {
width: 35em;
margin: 0 auto;
font-family: Tahoma, Verdana, Arial, sans-serif;
}
</style>
</head>
<body>
<h1>Welcome to nginx!</h1>
<p>If you see this page, the nginx web server is successfully installed and
working. Further configuration is required.</p>
<p>For online documentation and support please refer to
<a href="http://nginx.org/">nginx.org</a>.<br/>
Commercial support is available at
<a href="http://nginx.com/">nginx.com</a>.</p>
<p><em>Thank you for using nginx.</em></p>
</body>
</html>
有一個節點發現不可以訪問，重啓一下flannel和docker
[root@node02 ~]# curl 10.0.0.31
^C
[root@node02 ~]# systemctl restart flanneld.service
[root@node02 ~]# systemctl restart docker
[root@node02 system]# curl 10.0.0.31
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>
body {
width: 35em;
margin: 0 auto;
font-family: Tahoma, Verdana, Arial, sans-serif;
}
</style>
</head>
<body>
<h1>Welcome to nginx!</h1>
<p>If you see this page, the nginx web server is successfully installed and
working. Further configuration is required.</p>
<p>For online documentation and support please refer to
<a href="http://nginx.org/">nginx.org</a>.<br/>
Commercial support is available at
<a href="http://nginx.com/">nginx.com</a>.</p>
<p><em>Thank you for using nginx.</em></p>
</body>
</html>
然後另外一個node1節點發現又不可以了，
[root@node01 ~]# curl 10.0.0.31
^C
[root@node01 ~]#
3.4 創建headless無頭服務
因爲statefulset控制器創建的pod資源是一個動態的IP地址，ip地址不同，會影響服務的正常使用
所以常用於綁定dns訪問，這就要安裝dns服務
創建statefulset的pod資源
無頭服務：直接綁定podIP提供服務
headless service 無頭服務，不需要cluster-IP，直接綁定具體的POD的IP
[root@master1 gsy]# vim headless.yaml
apiVersion: v1
kind: Service
metadata:
name: nginx-headless
labels:
app: nginx
spec:
ports:
- port: 80
name: web
clusterIP: None #這個是無頭服務的核心
selector:
app: nginx
[root@master1 gsy]# kubectl apply -f headless.yaml
service/nginx-headless created
[root@master1 gsy]# kubectl get service
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kubernetes ClusterIP 10.0.0.1 <none> 443/TCP 14d
nginx-headless ClusterIP None <none> 80/TCP 4s
nginx-service NodePort 10.0.0.31 <none> 80:37384/TCP 14m
3.5 查看服務，出現一個沒有cluster-ip的服務
[root@master1 ~]# kubectl get svc
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kubernetes ClusterIP 10.0.0.1 <none> 443/TCP 16d
nginx-headless ClusterIP None <none> 80/TCP 45h
nginx-service NodePort 10.0.0.31 <none> 80:37384/TCP 46h
3.6 開始做dns服務
在集羣中定義的每個 Service（包括 DNS 服務器自身）都會被指派一個 DNS 名稱。 默認，一個客戶端 Pod 的 DNS 搜索列表將包含該 Pod 自己的 Namespace 和集羣默認域。
假設在 Kubernetes 集羣的 Namespace bar 中，定義了一個Service foo。 運行在Namespace bar 中的一個 Pod，可以簡單地通過 DNS 查詢 foo 來找到該 Service。 運行在 Namespace quux 中的一個 Pod 可以通過 DNS 查詢 foo.bar 找到該 Service。
從 Kubernetes v1.12 開始，CoreDNS 是推薦的 DNS 服務器，取代了kube-dns。 但是，默認情況下，某些 Kubernetes 安裝程序工具仍可能安裝 kube-dns。 請參閱安裝程序提供的文檔，以瞭解默認情況下安裝了哪個 DNS 服務器。
CoreDNS 的部署，作爲一個 Kubernetes 服務，通過靜態 IP 的方式暴露。 CoreDNS 和 kube-dns 服務在 metadata.name 字段中均被命名爲 kube-dns。 這樣做是爲了與依靠傳統 kube-dns 服務名稱來解析集羣內部地址的工作負載具有更大的互操作性。它抽象出哪個 DNS 提供程序在該公共端點後面運行的實現細節。
kubelet 使用 --cluster-dns = <dns-service-ip> 標誌將 DNS 傳遞到每個容器。
如果 Pod 的 dnsPolicy 設置爲 “default”，則它將從 Pod 運行所在節點上的配置中繼承名稱解析配置。 Pod 的 DNS 解析應該與節點相同。
如果您不想這樣做，或者想要爲 Pod 使用其他 DNS 配置，則可以 使用 kubelet 的 --resolv-conf 標誌。 將此標誌設置爲 "” 以避免 Pod 繼承 DNS。 將其設置爲有效的文件路徑以指定除以下以外的文件 /etc/resolv.conf，用於 DNS 繼承
3.7 創建dns的服務
[root@master1 ~]# cp /abc/k8s/coredns.yaml .
[root@master1 ~]# cat coredns.yaml #這個
apiVersion: v1
kind: ServiceAccount #爲Pod中的進程和外部用戶提供身份信息，系統賬戶
metadata:
name: coredns
namespace: kube-system
labels:
kubernetes.io/cluster-service: "true"
addonmanager.kubernetes.io/mode: Reconcile
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole #ClusterRole對象可以授予整個集羣範圍內資源訪問權限
metadata:
labels:
kubernetes.io/bootstrapping: rbac-defaults
addonmanager.kubernetes.io/mode: Reconcile
name: system:coredns
rules:
- apiGroups:
- ""
resources:
- endpoints
- services
- pods
- namespaces
verbs:
- list
- watch
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding #RoleBinding可以將同一namespace中的subject（用戶）
綁定到某個具有特定權限的Role下，則此subject即具有該Role定義的權限。
metadata:
annotations:
rbac.authorization.kubernetes.io/autoupdate: "true"
labels:
kubernetes.io/bootstrapping: rbac-defaults
addonmanager.kubernetes.io/mode: EnsureExists
name: system:coredns
roleRef:
apiGroup: rbac.authorization.k8s.io
kind: ClusterRole
name: system:coredns
subjects:
- kind: ServiceAccount
name: coredns
namespace: kube-system
---
#CoreDNS 是模塊化且可插拔的 DNS 服務器，每個插件都爲 CoreDNS 添加了新功能
#可以通過維護Corefile，即CoreDNS 配置文件。
#集羣管理員可以修改 CoreDNS Corefile 的 ConfigMap，以更改服務發現的工作方式。
#在 Kubernetes 中，已經使用以下默認 Corefile 配置安裝了 CoreDNS。
Corefile 配置包括以下 CoreDNS 的 插件：
錯誤：錯誤記錄到 stdout。
健康：CoreDNS 的健康報告給 http://localhost:8080/health。
kubernetes：CoreDNS 將基於 Kubernetes 的服務和 Pod 的 IP 答覆 DNS 查詢。
apiVersion: v1
kind: ConfigMap
metadata:
name: coredns
namespace: kube-system
labels:
addonmanager.kubernetes.io/mode: EnsureExists
data:
Corefile: |
.:53 {
errors
health
kubernetes cluster.local in-addr.arpa ip6.arpa {
pods insecure #與kube-dns向前兼容
#可以使用 pods verified 選項，該選項僅在相同名稱空間中存在具有匹配 IP 的 pod 時才返回 A 記錄。
#如果您不使用 Pod 記錄，則可以使用 pods disabled 選項。
upstream #用來解析指向外部主機的服務
fallthrough in-addr.arpa ip6.arpa
}
prometheus :9153
#CoreDNS的度量標準以Prometheus格式在 http://localhost:9153/metrics 上提供。
proxy . /etc/resolv.conf
#不在 Kubernetes 集羣域內的任何查詢都將轉發到預定義的解析器 (/etc/resolv.conf).
cache 30
#啓用前端緩存
loop
#檢測到簡單的轉發循環，如果發現死循環，則中止 CoreDNS 進程。
reload
#允許自動重新加載已更改的 Corefile。 編輯 ConfigMap 配置後，請等待兩分鐘，以使更改生效。
loadbalance
#輪詢 DNS 負載均衡器，它在應答中隨機分配 A，AAAA 和 MX 記錄的順序。
}
#修改 ConfigMap 來修改默認的 CoreDNS 行爲。
CoreDNS 能夠使用 proxy plugin. 配置存根域和上游域名服務器。
使用 CoreDN 配置存根域和上游域名服務器見官方文檔
---
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
name: coredns
namespace: kube-system
labels:
k8s-app: kube-dns
kubernetes.io/cluster-service: "true"
addonmanager.kubernetes.io/mode: Reconcile
kubernetes.io/name: "CoreDNS"
spec:
# replicas: not specified here:
# 1. In order to make Addon Manager do not reconcile this replicas parameter.
# 2. Default is 1.
# 3. Will be tuned in real time if DNS horizontal auto-scaling is turned on.
strategy:
type: RollingUpdate
rollingUpdate:
maxUnavailable: 1
selector:
matchLabels:
k8s-app: kube-dns
template:
metadata:
labels:
k8s-app: kube-dns
annotations:
seccomp.security.alpha.kubernetes.io/pod: 'docker/default'
spec:
serviceAccountName: coredns
tolerations:
- key: node-role.kubernetes.io/master
effect: NoSchedule
- key: "CriticalAddonsOnly"
operator: "Exists"
containers:
- name: coredns
image: coredns/coredns:1.2.2
imagePullPolicy: IfNotPresent
resources:
limits:
memory: 170Mi
requests:
cpu: 100m
memory: 70Mi
args: [ "-conf", "/etc/coredns/Corefile" ]
volumeMounts:
- name: config-volume
mountPath: /etc/coredns
readOnly: true
ports:
- containerPort: 53
name: dns
protocol: UDP
- containerPort: 53
name: dns-tcp
protocol: TCP
- containerPort: 9153
name: metrics
protocol: TCP
livenessProbe:
httpGet:
path: /health
port: 8080
scheme: HTTP
initialDelaySeconds: 60
timeoutSeconds: 5
successThreshold: 1
failureThreshold: 5
securityContext:
allowPrivilegeEscalation: false
capabilities:
add:
- NET_BIND_SERVICE
drop:
- all
readOnlyRootFilesystem: true
dnsPolicy: Default
volumes:
- name: config-volume
configMap:
name: coredns
items:
- key: Corefile
path: Corefile
---
apiVersion: v1
kind: Service
metadata:
name: kube-dns
namespace: kube-system
annotations:
prometheus.io/port: "9153"
prometheus.io/scrape: "true"
labels:
k8s-app: kube-dns
kubernetes.io/cluster-service: "true"
addonmanager.kubernetes.io/mode: Reconcile
kubernetes.io/name: "CoreDNS"
spec:
selector:
k8s-app: kube-dns
clusterIP: 10.0.0.2
ports:
- name: dns
port: 53
protocol: UDP
- name: dns-tcp
port: 53
protocol: TCP
[root@master1 ~]# ls -l
total 64
-rw-r--r--. 1 root root 191 May 13 14:45 1nodeselector.yaml
-rw-------. 1 root root 1935 Apr 30 08:53 anaconda-ks.cfg
-rwxr-xr-x. 1 root root 4290 May 17 08:49 coredns.yaml
3.8 查看創建後的狀態
[root@master1 ~]# kubectl create -f coredns.yaml
serviceaccount/coredns created
clusterrole.rbac.authorization.k8s.io/system:coredns created
clusterrolebinding.rbac.authorization.k8s.io/system:coredns created
configmap/coredns created
deployment.extensions/coredns created
service/kube-dns created
[root@master1 ~]# kubectl get all -n kube-system
NAME READY STATUS RESTARTS AGE
pod/coredns-56684f94d6-qfkf7 1/1 Running 0 24s
pod/kubernetes-dashboard-7dffbccd68-l4tcd 1/1 Running 2 8d
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
service/kube-dns ClusterIP 10.0.0.2 <none> 53/UDP,53/TCP 24s
service/kubernetes-dashboard NodePort 10.0.0.237 <none> 443:30001/TCP 8d
NAME DESIRED CURRENT UP-TO-DATE AVAILABLE AGE
deployment.apps/coredns 1 1 1 1 24s
deployment.apps/kubernetes-dashboard 1 1 1 1 8d
NAME DESIRED CURRENT READY AGE
replicaset.apps/coredns-56684f94d6 1 1 1 24s
replicaset.apps/kubernetes-dashboard-65f974f565 0 0 0 8d
replicaset.apps/kubernetes-dashboard-7dffbccd68 1 1 1 8d
3.9 創建一個測試pod資源
[root@master1 ~]# vim pod3.yaml
apiVersion: v1
kind: Pod
metadata:
name: dns-test
spec:
containers:
- name: busybox
image: busybox:1.28.4
args:
- /bin/sh
- -c
- sleep 36000
restartPolicy: Never
[root@master1 ~]# kubectl create -f pod3.yaml
3.10 驗證dns解析
[root@master1 ~]# kubectl get svc
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kubernetes ClusterIP 10.0.0.1 <none> 443/TCP 16d
nginx-headless ClusterIP None <none> 80/TCP 46h
nginx-service NodePort 10.0.0.31 <none> 80:37384/TCP 46h
[root@master1 ~]# kubectl get pods
NAME READY STATUS RESTARTS AGE
dns-test 1/1 Running 0 47s
3.11 解析kubernetes和nginx-service名稱
[root@master1 ~]# kubectl exec -it dns-test sh
[root@master1 ~]# kubectl exec -it dns-test sh
/ # nslookup kubernetes
Server: 10.0.0.2
Address 1: 10.0.0.2
nslookup: can't resolve 'kubernetes'
/ # exit
3.12 nodes節點重啓一下flanneld組件和docker
[root@node01 ~]# systemctl restart flanneld
[root@node01 ~]# systemctl restart docker
可以了
[root@master1 ~]# kubectl exec -it dns-test sh
/ # nslookup kubernetes
Server: 10.0.0.2
Address 1: 10.0.0.2 kube-dns.kube-system.svc.cluster.local
Name: kubernetes
Address 1: 10.0.0.1 kubernetes.default.svc.cluster.local
/ # nslookup nginx-service
Server: 10.0.0.2
Address 1: 10.0.0.2 kube-dns.kube-system.svc.cluster.local
Name: nginx-service
Address 1: 10.0.0.31 nginx-service.default.svc.cluster.local
/ # nslookup nginx-deployment-78cdb5b557-lt52n.nginx
Server: 10.0.0.2
Address 1: 10.0.0.2 kube-dns.kube-system.svc.cluster.local
nslookup: can't resolve 'nginx-deployment-78cdb5b557-lt52n.nginx'
^C[root@master1 ~]# kubectl get svc -o wide
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE SELECTOR
kubernetes ClusterIP 10.0.0.1 <none> 443/TCP 16d <none>
nginx-headless ClusterIP None <none> 80/TCP 47h app=nginx
nginx-service NodePort 10.0.0.31 <none> 80:37384/TCP 47h app=nginx
dns 可以解析資源名稱
3.13 創建statefulset 資源
無頭服務就是沒有clusterIP，他的IP是動態的
[root@master1 ~]# vim statefulset.yaml
apiVersion: v1
kind: Service
metadata:
name: nginx
labels:
app: nginx
spec:
ports:
- port: 80
name: web
clusterIP: None
selector:
app: nginx
---
apiVersion: apps/v1beta1
kind: StatefulSet
metadata:
name: nginx-statefulset
namespace: default
spec:
serviceName: nginx
replicas: 3
selector:
matchLabels:
app: nginx
template:
metadata:
labels:
app: nginx
spec:
containers:
- name: nginx
image: nginx:latest
ports:
- containerPort: 80
3.14 創建前先清理下之前的環境
[root@master1 ~]# rm -rf coredns.yaml
[root@master1 ~]# kubectl delete -f .
[root@master1 ~]# kubectl apply -f statefulset.yaml
service/nginx created
statefulset.apps/nginx-statefulset created
[root@master1 ~]# kubectl get pods
NAME READY STATUS RESTARTS AGE
nginx-deployment-78cdb5b557-c2cwv 1/1 Running 2 2d2h
nginx-deployment-78cdb5b557-d6wlp 1/1 Running 1 2d2h
nginx-deployment-78cdb5b557-lt52n 1/1 Running 1 2d2h
nginx-statefulset-0 0/1 ContainerCreating 0 12s
[root@master1 ~]# kubectl get pods -w
NAME READY STATUS RESTARTS AGE
nginx-deployment-78cdb5b557-c2cwv 1/1 Running 2 2d2h
nginx-deployment-78cdb5b557-d6wlp 1/1 Running 1 2d2h
nginx-deployment-78cdb5b557-lt52n 1/1 Running 1 2d2h
nginx-statefulset-0 1/1 Running 0 24s
nginx-statefulset-1 0/1 ContainerCreating 0 11s
nginx-statefulset-1 1/1 Running 0 15s
nginx-statefulset-2 0/1 Pending 0 0s
nginx-statefulset-2 0/1 Pending 0 0s
nginx-statefulset-2 0/1 ContainerCreating 0 0s
nginx-statefulset-2 1/1 Running 0 4s
^C[root@master1 ~]# kubectl get svc,deploy
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
service/kubernetes ClusterIP 10.0.0.1 <none> 443/TCP 17d
service/nginx ClusterIP None <none> 80/TCP 63s
service/nginx-headless ClusterIP None <none> 80/TCP 2d
service/nginx-service NodePort 10.0.0.31 <none> 80:37384/TCP 2d
NAME DESIRED CURRENT UP-TO-DATE AVAILABLE AGE
deployment.extensions/nginx-deployment 3 3 3 3 2d2h
[root@master1 ~]# kubectl delete svc nginx-headless
service "nginx-headless" deleted
[root@master1 ~]# kubectl delete svc nginx-service
service "nginx-service" deleted
- 順序創建Pod
對於一個擁有 N 個副本的 StatefulSet，Pod 被部署時是按照 {0 …… N-1} 的序號順序創建的。在第一個終端中使用 kubectl get 檢查輸出
備註：在 nginx-statefulset-0 Pod 處於 Running和Ready 狀態後 nginx-statefulset-1 Pod 纔會被啓動。
StatefulSet 中的 Pod 擁有一個唯一的順序索引和穩定的網絡身份標識。
這個標誌基於 StatefulSet 控制器分配給每個 Pod 的唯一順序索引。Pod 的名稱的形式爲<statefulset name>-<ordinal index>
每個 Pod 都擁有一個基於其順序索引的穩定的主機名
3.15 創建測試dns容器
[root@master1 ~]# kubectl apply -f pod3.yaml
pod/dns-test created
[root@master1 ~]# kubectl exec -it dns-test sh
/ # nslookup nginx
Server: 10.0.0.2
Address 1: 10.0.0.2 kube-dns.kube-system.svc.cluster.local
Name: nginx
Address 1: 172.17.88.5 nginx-statefulset-2.nginx.default.svc.cluster.local
Address 2: 172.17.88.4 nginx-statefulset-0.nginx.default.svc.cluster.local
Address 3: 172.17.57.2 172-17-57-2.nginx.default.svc.cluster.local
Address 4: 172.17.57.5 nginx-statefulset-1.nginx.default.svc.cluster.local
Address 5: 172.17.57.4 172-17-57-4.nginx.default.svc.cluster.local
Address 6: 172.17.88.3 172-17-88-3.nginx.default.svc.cluster.local
/ # nslookup nginx-statefulset-0
Server: 10.0.0.2
Address 1: 10.0.0.2 kube-dns.kube-system.svc.cluster.local
^C
/ # nslookup nginx-statefulset-0.nginx
Server: 10.0.0.2
Address 1: 10.0.0.2 kube-dns.kube-system.svc.cluster.local
Name: nginx-statefulset-0.nginx
Address 1: 172.17.88.4 nginx-statefulset-0.nginx.default.svc.cluster.local
備註：可以手動將statefulset的pod刪掉，然後K8S會根據控制器的副本數量自動重新創建，此時再次解析，會發現IP地址會變化
3.16 查看網絡
[root@master1 ~]# kubectl get all -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE
pod/dns-test 1/1 Running 0 5m49s 172.17.57.6 192.168.247.143 <none>
pod/nginx-deployment-78cdb5b557-c2cwv 1/1 Running 2 2d2h 172.17.88.3 192.168.247.144 <none>
pod/nginx-deployment-78cdb5b557-d6wlp 1/1 Running 1 2d2h 172.17.57.2 192.168.247.143 <none>
pod/nginx-deployment-78cdb5b557-lt52n 1/1 Running 1 2d2h 172.17.57.4 192.168.247.143 <none>
pod/nginx-statefulset-0 1/1 Running 0 8m50s 172.17.88.4 192.168.247.144 <none>
pod/nginx-statefulset-1 1/1 Running 0 8m37s 172.17.57.5 192.168.247.143 <none>
pod/nginx-statefulset-2 1/1 Running 0 8m22s 172.17.88.5 192.168.247.144 <none>
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE SELECTOR
service/kubernetes ClusterIP 10.0.0.1 <none> 443/TCP 17d <none>
service/nginx ClusterIP None <none> 80/TCP 8m50s app=nginx
NAME DESIRED CURRENT UP-TO-DATE AVAILABLE AGE CONTAINERS IMAGES SELECTOR
deployment.apps/nginx-deployment 3 3 3 3 2d2h nginx1 nginx:1.15.4 app=nginx
NAME DESIRED CURRENT READY AGE CONTAINERS IMAGES SELECTOR
replicaset.apps/nginx-deployment-78cdb5b557 3 3 3 2d2h nginx1 nginx:1.15.4 app=nginx,pod-template-hash=78cdb5b557
NAME DESIRED CURRENT AGE CONTAINERS IMAGES
statefulset.apps/nginx-statefulset 3 3 8m50s nginx nginx:latest
3.17 總結
statefulset與deployment的區別之一，statefulset還有一個身份
身份三要素
域名：nginx-statefulset-0.nginx
主機名：nginx-statefulset-0
存儲(PVC)
序列編號區分唯一身份
statefulset適用於podIP會一直變化的情況
順序終止 Pod
控制器會按照與 Pod 序號索引相反的順序每次刪除一個 Pod。在刪除下一個 Pod 前會等待上一個被完全關閉。
更新 StatefulSet
StatefulSet 裏的 Pod 採用和序號相反的順序更新。在更新下一個 Pod 前，StatefulSet 控制器終止每個 Pod 並等待它們變成 Running 和 Ready。請注意，雖然在順序後繼者變成 Running 和 Ready 之前 StatefulSet 控制器不會更新下一個 Pod，但它仍然會重建任何在更新過程中發生故障的 Pod，使用的是它們當前的版本。已經接收到更新請求的 Pod 將會被恢復爲更新的版本，沒有收到請求的 Pod 則會被恢復爲之前的版本。像這樣，控制器嘗試繼續使應用保持健康並在出現間歇性故障時保持更新的一致性。
四：daemonset
4.1 概述
在每一個node上運行一個pod，新加入的node同樣會自動運行一個pod
應用場景：代理，監控，比如elk中的logstash 或者efk中的firebeat
官方文檔：https://kubernetes.io/docs/concepts/workloads/controllers/daemonset/
4.2 演示
volumemounts是pod的掛載點
[root@master1 ~]# vim daemonset.yaml
apiVersion: apps/v1
kind: DaemonSet
metadata:
name: nginx-daemonset
labels:
app: nginx
spec:
selector:
matchLabels:
app: nginx
template:
metadata:
labels:
app: nginx
spec:
containers:
- name: nginx
image: nginx:1.15.4
ports:
- containerPort: 80
4.2.1 創建daemonset資源
[root@master1 ~]# kubectl apply -f daemonset.yaml
daemonset.apps/nginx-daemonset created
^C[root@master1 ~]# kubectl get pods -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE
dns-test 1/1 Running 0 9m9s 172.17.57.6 192.168.247.143 <none>
nginx-daemonset-8mdhj 1/1 Running 0 41s 172.17.88.6 192.168.247.144 <none>
nginx-daemonset-ggdv2 1/1 Running 0 41s 172.17.57.7 192.168.247.143 <none>
nginx-deployment-78cdb5b557-c2cwv 1/1 Running 2 2d2h 172.17.88.3 192.168.247.144 <none>
nginx-deployment-78cdb5b557-d6wlp 1/1 Running 1 2d2h 172.17.57.2 192.168.247.143 <none>
nginx-deployment-78cdb5b557-lt52n 1/1 Running 1 2d2h 172.17.57.4 192.168.247.143 <none>
nginx-statefulset-0 1/1 Running 0 12m 172.17.88.4 192.168.247.144 <none>
nginx-statefulset-1 1/1 Running 0 11m 172.17.57.5 192.168.247.143 <none>
nginx-statefulset-2 1/1 Running 0 11m 172.17.88.5 192.168.247.144 <none>
daemonset會在每個node節點上都創建一個pods
五：job
job分爲普通任務（job）和定時任務（cronjob）
5.1 job 一次性執行
應用場景：離線數據處理，視頻解碼等業務
大數據分析計算的服務
官方文檔：https://kubernetes.io/docs/concepts/workloads/controllers/jobs-run-to-completion/
5.1.1 演示
重試次數默認是6次，修改爲4次，當遇到異常時Never狀態會重啓，所以要設定次數。
回滾次數限制爲4次
[root@master1 ~]# vim job.yaml
apiVersion: batch/v1
kind: Job
metadata:
name: pi
spec:
template:
spec:
containers:
- name: pi
image: perl
command: ["perl", "-Mbignum=bpi", "-wle", "print bpi(2000)"]
restartPolicy: Never
backoffLimit: 4
5.1.2 創建job
[root@master1 ~]# kubectl apply -f job.yaml
job.batch/pi created
[root@master1 ~]# kubectl get pods -w
NAME READY STATUS RESTARTS AGE
pi-9jf2w 0/1 ContainerCreating 0 4s
pi-9jf2w 1/1 Running 0 62s
pi-9jf2w 0/1 Completed 0 76s
^C[root@master1 ~]#
^C[root@master1 ~]# kubectl logs pi-9jf2w
3.1415926535897932384626433832795028841971693993751058209749445923078164062862089986280348253421170679821480865132823066470938446095505822317253594081284811174502841027019385211055596446229489549303819644288109756659334461284756482337867831652712019091456485669234603486104543266482133936072602491412737245870066063155881748815209209628292540917153643678925903600113305305488204665213841469519415116094330572703657595919530921861173819326117931051185480744623799627495673518857527248912279381830119491298336733624406566430860213949463952247371907021798609437027705392171762931767523846748184676694051320005681271452635608277857713427577896091736371787214684409012249534301465495853710507922796892589235420199561121290219608640344181598136297747713099605187072113499999983729780499510597317328160963185950244594553469083026425223082533446850352619311881710100031378387528865875332083814206171776691473035982534904287554687311595628638823537875937519577818577805321712268066130019278766111959092164201989380952572010654858632788659361533818279682303019520353018529689957736225994138912497217752834791315155748572424541506959508295331168617278558890750983817546374649393192550604009277016711390098488240128583616035637076601047101819429555961989467678374494482553797747268471040475346462080466842590694912933136770289891521047521620569660240580381501935112533824300355876402474964732639141992726042699227967823547816360093417216412199245863150302861829745557067498385054945885869269956909272107975093029553211653449872027559602364806654991198818347977535663698074265425278625518184175746728909777727938000816470600161452491921732172147723501414419735685481613611573525521334757418494684385233239073941433345477624168625189835694855620992192221842725502542568876717904946016534668049886272327917860857843838279679766814541009538837863609506800642251252051173929848960841284886269456042419652850222106611863067442786220391949450471237137869609563643719172874677646575739624138908658326459958133904780275901
5.1.3 查看job資源
[root@master1 ~]# kubectl get job
NAME COMPLETIONS DURATION AGE
pi 1/1 76s 2m57s
#此時若用kubectl get all也可以看到job資源
5.1.4 清除job資源
[root@master1 ~]# kubectl delete -f job.yaml
job.batch "pi" deleted
5.2 cronjob 週期性任務
類似於linux中的crontab
應用場景：定時通知，定時備份
https://kubernetes.io/docs/tasks/job/automated-tasks-with-cron-jobs/
5.2.1 演示
建立每分鐘打印hello的任務
[root@master1 ~]# vim cronjob.yaml
apiVersion: batch/v1beta1
kind: CronJob
metadata:
name: hello
spec:
schedule: "*/1 * * * *"
jobTemplate:
spec:
template:
spec:
containers:
- name: hello
image: busybox
args:
- /bin/sh
- -c
- date; echo Hello from the Kubernetes cluster
restartPolicy: OnFailure
5.2.2 查看cronjob資源
[root@master1 ~]# kubectl get cronjob
No resources found.
[root@master1 ~]# kubectl apply -f cronjob.yaml
cronjob.batch/hello created
[root@master1 ~]# kubectl get cronjob
NAME SCHEDULE SUSPEND ACTIVE LAST SCHEDULE AGE
hello */1 * * * * False 0 <none> 2s
5.2.3 -w查看pod運行狀態
[root@master1 ~]# kubectl get pods
NAME READY STATUS RESTARTS AGE
dns-test 1/1 Running 0 27m
hello-1589686080-qtc4c 0/1 ContainerCreating 0 3s
[root@master1 ~]# kubectl get pods -w
NAME READY STATUS RESTARTS AGE
dns-test 1/1 Running 0 28m
hello-1589686080-qtc4c 0/1 ContainerCreating 0 7s
hello-1589686080-qtc4c 1/1 Running 0 11s
hello-1589686080-qtc4c 0/1 Completed 0 12s
hello-1589686140-tj66f 0/1 Pending 0 0s
hello-1589686140-tj66f 0/1 ContainerCreating 0 0s
hello-1589686140-tj66f 0/1 Completed 0 9s
hello-1589686200-phc6t 0/1 Pending 0 0s
hello-1589686200-phc6t 0/1 ContainerCreating 0 0s
hello-1589686200-phc6t 0/1 Completed 0 8s
hello-1589686260-dg6gp 0/1 Pending 0 0s
hello-1589686260-dg6gp 0/1 ContainerCreating 0 0s
hello-1589686260-dg6gp 0/1 Completed 0 13s
hello-1589686080-qtc4c 0/1 Terminating 0 3m21s
hello-1589686320-n9r2f 0/1 Pending 0 0s
hello-1589686320-n9r2f 0/1 ContainerCreating 0 0s
^C[root@master1 ~]# kubectl get pods
NAME READY STATUS RESTARTS AGE
dns-test 1/1 Running 0 32m
hello-1589686140-tj66f 0/1 Completed 0 3m16s
hello-1589686200-phc6t 0/1 Completed 0 2m15s
hello-1589686260-dg6gp 0/1 Completed 0 75s
hello-1589686320-n9r2f 0/1 ContainerCreating 0 15s
5.2.4 查看log日誌中的反饋信息
[root@master1 ~]# kubectl logs hello-1589686380-flrtj
Sun May 17 03:33:24 UTC 2020
Hello from the Kubernetes cluster
[root@master1 ~]# kubectl logs hello-1589686440-ngj59
Sun May 17 03:34:19 UTC 2020
Hello from the Kubernetes cluster
[root@master1 ~]# kubectl delete -f cronjob.yaml
cronjob.batch "hello" deleted
[root@master1 ~]# kubectl get pods
NAME READY STATUS RESTARTS AGE
dns-test 1/1 Running 0 35m
備註：使用完cronjob要慎重，用完之後要刪掉，不然會佔用很多資源