7. DaemonSet
https://www.cnblogs.com/Netsharp/p/15501138.html
DaemonSet：它叫守护进程集缩写为ds,在所有节点或者是匹配的节点上都部署一个Pod
DaemonSet:在当前集群中每个节点运行同一个Pod，当有新的节点加入集群时也会为新的节点配置相同的Pod，当节点从集群中移除时其Pod也会被kubernetes回收，删除DaemonSet控制器将删除其创建的所有的Pod
例如：
运行集群存储的daemon，比如ceph或者glusterd
节点的CNI网络插件
节点日志的收集：filebeat
节点的监控： node exporter
服务暴露：部署一个ingress nginx
7.1 定义一个DaemonSet资源
[root@master01 daemonset]# cat nginx-ds.yaml
apiVersion: apps/v1
kind: DaemonSet
metadata:
labels:
app: nginx
name: nginx
namespace: default
spec:
revisionHistoryLimit: 10 # 历史记录保留的个数
selector:
matchLabels:
app: nginx
template:
metadata:
labels:
app: nginx
spec:
containers:
- image: nginx:1.15.2
imagePullPolicy: IfNotPresent
name: nginx
resources: {}
terminationMessagePath: /dev/termination-log
terminationMessagePolicy: File
dnsPolicy: ClusterFirst
restartPolicy: Always
schedulerName: default-scheduler
securityContext: {}
terminationGracePeriodSeconds: 30
#查看是否创建成功
[root@master01 daemonset]# kubectl get ds
NAME DESIRED CURRENT READY UP-TO-DATE AVAILABLE NODE SELECTOR AGE
nginx 3 3 2 3 2 <none> 4s
#这里已经成功了 因为我有三个节点所以有三个POD
[root@master01 daemonset]# kubectl get pods
NAME READY STATUS RESTARTS AGE
busybox 1/1 Running 2 122m
nginx-cmn4t 1/1 Running 0 9s
nginx-sbrjh 1/1 Running 0 9s
nginx-z6j6h 1/1 Running 0 9s
7.2 指定标签调度
#先创建两个标签 准备调度
[root@master01 daemonset]# kubectl label nodes node01 ds=true
node/node01 labeled
[root@master01 daemonset]# kubectl label nodes node02 ds=true
node/node02 labeled
#查看节点的Pod 标签是否成功
[root@master01 daemonset]# kubectl get nodes --show-labels
#nodeSelector 标签选择器
[root@master01 daemonset]# cat nginx-ds.yaml
apiVersion: apps/v1
kind: DaemonSet
metadata:
labels:
app: nginx
name: nginx
namespace: default
spec:
revisionHistoryLimit: 10 # 历史记录保留的个数
selector:
matchLabels:
app: nginx
template:
metadata:
labels:
app: nginx
spec:
nodeSelector:
ds: "true"
containers:
- image: nginx:1.15.2
imagePullPolicy: IfNotPresent
name: nginx
resources: {}
terminationMessagePath: /dev/termination-log
terminationMessagePolicy: File
dnsPolicy: ClusterFirst
restartPolicy: Always
schedulerName: default-scheduler
securityContext: {}
terminationGracePeriodSeconds: 30
#再次查看Pod状态 你会发现没有 ds=true的标签就会被删除掉 只留下存在标签的
[root@master01 daemonset]# kubectl get pods
NAME READY STATUS RESTARTS AGE
busybox 1/1 Running 2 129m
nginx-cmn4t 1/1 Running 0 6m51s
nginx-sbrjh 0/1 Terminating 0 6m51s
nginx-z6j6h 0/1 Terminating 0 6m51s
[root@master01 daemonset]# kubectl get pods
NAME READY STATUS RESTARTS AGE
busybox 1/1 Running 2 136m
nginx-j86d8 1/1 Running 0 7m22s
nginx-vs22j 1/1 Running 0 7m32s
#如果想把删除的Pod在加进来、重新给他添加一个标签即可
[root@master01 daemonset]# kubectl label nodes node03 ds=true
node/node03 labeled
#打上这个标签后会自动的运行Pod
[root@master01 daemonset]# kubectl get pods
NAME READY STATUS RESTARTS AGE
busybox 1/1 Running 2 140m
nginx-j86d8 1/1 Running 0 10m
nginx-vs22j 1/1 Running 0 11m
nginx-zdpnm 1/1 Running 0 13s
7.3 回滚
#daemonset不建议使用RollingUpdate影响很高 建议使用OnDelet
#默认是RollingUpdate 滚动更新
[root@master01 daemonset]# kubectl edit ds nginx
updateStrategy:
rollingUpdate:
maxUnavailable: 1
type: RollingUpdate
#然后就更新成功了
[root@master01 daemonset]# kubectl get pods
NAME READY STATUS RESTARTS AGE
busybox 1/1 Running 2 148m
nginx-hzptc 1/1 Running 0 2m45s
nginx-s2twh 1/1 Running 0 2m39s
nginx-t2754 1/1 Running 0 2m21s
#建议使用
updateStrategy:
type: OnDelete
#删除一个pod才会触发更新
[root@master01 daemonset]# kubectl delete pod nginx-hzptc
pod "nginx-hzptc" deleted
#也可以查看历史版本
[root@master01 daemonset]# kubectl rollout history ds nginx
7.4 部署一个web例子
root@deploy-harbor:~/20220731/k8s-Resource-N70/case13-DaemonSet# cat 1-DaemonSet-webserver.yaml
---
#apiVersion: extensions/v1beta1
apiVersion: apps/v1
kind: DaemonSet
metadata:
name: myserver-myapp
namespace: myserver
spec:
selector:
matchLabels:
app: myserver-myapp-frontend
template:
metadata:
labels:
app: myserver-myapp-frontend
spec:
tolerations:
# this toleration is to have the daemonset runnable on master nodes
# remove it if your masters can't run pods
- key: node-role.kubernetes.io/master
operator: Exists
effect: NoSchedule
hostNetwork: true
hostPID: true
containers:
- name: myserver-myapp-frontend
image: nginx:1.20.2-alpine
ports:
- containerPort: 80
---
apiVersion: v1
kind: Service
metadata:
name: myserver-myapp-frontend
namespace: myserver
spec:
ports:
- name: http
port: 80
targetPort: 80
nodePort: 30018
protocol: TCP
type: NodePort
selector:
app: myserver-myapp-frontend
7.5 部署日志收集例
root@deploy-harbor:~/20220731/k8s-Resource-N70/case13-DaemonSet# cat 2-DaemonSet-fluentd.yaml
apiVersion: apps/v1
kind: DaemonSet
metadata:
name: fluentd-elasticsearch
namespace: kube-system
labels:
k8s-app: fluentd-logging
spec:
selector:
matchLabels:
name: fluentd-elasticsearch
template:
metadata:
labels:
name: fluentd-elasticsearch
spec:
tolerations:
# this toleration is to have the daemonset runnable on master nodes
# remove it if your masters can't run pods
- key: node-role.kubernetes.io/master
operator: Exists
effect: NoSchedule
containers:
- name: fluentd-elasticsearch
image: quay.io/fluentd_elasticsearch/fluentd:v2.5.2
resources:
limits:
memory: 200Mi
requests:
cpu: 100m
memory: 200Mi
volumeMounts:
- name: varlog
mountPath: /var/log
- name: varlibdockercontainers
mountPath: /var/lib/docker/containers
readOnly: true
terminationGracePeriodSeconds: 30
volumes:
- name: varlog
hostPath:
path: /var/log
- name: varlibdockercontainers
hostPath:
path: /var/lib/docker/containers
7.6 部署prometheus例
root@deploy-harbor:~/20220731/k8s-Resource-N70/case13-DaemonSet# cat 3-DaemonSet-prometheus.yaml
apiVersion: apps/v1
kind: DaemonSet
metadata:
name: node-exporter
namespace: monitoring
labels:
k8s-app: node-exporter
spec:
selector:
matchLabels:
k8s-app: node-exporter
template:
metadata:
labels:
k8s-app: node-exporter
spec:
tolerations:
- effect: NoSchedule
key: node-role.kubernetes.io/master
containers:
- image: prom/node-exporter:v1.3.1
imagePullPolicy: IfNotPresent
name: prometheus-node-exporter
ports:
- containerPort: 9100
hostPort: 9100
protocol: TCP
name: metrics
volumeMounts:
- mountPath: /host/proc
name: proc
- mountPath: /host/sys
name: sys
- mountPath: /host
name: rootfs
args:
- --path.procfs=/host/proc
- --path.sysfs=/host/sys
- --path.rootfs=/host
volumes:
- name: proc
hostPath:
path: /proc
- name: sys
hostPath:
path: /sys
- name: rootfs
hostPath:
path: /
hostNetwork: true
hostPID: true
---
apiVersion: v1
kind: Service
metadata:
annotations:
prometheus.io/scrape: "true"
labels:
k8s-app: node-exporter
name: node-exporter
namespace: monitoring
spec:
type: NodePort
ports:
- name: http
port: 9100
nodePort: 39100
protocol: TCP
selector:
k8s-app: node-exporter
