介绍了Kubernetes中如何使用探针进行Pod健康检查
掌握存活探针的概念和使用方式
掌握就绪探针的概念和使用方式
目录
- Pod探针基本概念
- 使用存活探针
- 使用就绪探针
1.Pod探针基本概念
1.1 Pod状态
-
Pod的状态信息在PodStatus中定义，其中有一个phase字段，就是我们熟悉的以下一些状态。
image.png
1.2 更准确的判断Pod状态
- Kubernetes借助探针（Probes）机制，探针可以会周期性的监测容器运行的状态，
返回结果
Liveness探针：存活探针。Liveness探针用户捕获容器的状态是否处于存活状态。如果探测失败，kubelet会根据重启策略尝试恢复容器。
Readiness探针：就绪探针。如果readiness探针探测失败，则kubelet认为该容器没有准备好对外提供服务，则endpointcontroller会从与pod匹配的所有服务的端点中删除该Pod的地址。
1.3 存活探针和就绪探针对比
- 就 绪 探 针 与 存 活 探 针 一 致 ， 可 以 使 用 ExecAction ， TCPSocketAction , HTTPGetAction三种方法
-
就绪探针用于检测和显示Pod是否已经准备好对外提供业务。在实际使用场景中，就绪探针需要和业务绑定
image.png
[图片上传中...(image.png-441724-1645689273374-0)]
1.4 容器探针
- Kubelet可以周期性的执行Container的诊断。为了执行诊断，kubelet调用Container实现的Handler，有三种Handler类型。执行的周期用户自定义，每隔多久探测一次等等参数。
ExecAction：在容器内执行指定命令，如果命令退出时返回码为0（表示命令成功执行了），则认为诊断成功。
TCPSocketAction：对指定端口上的容器的Ip地址进行TCP检查。如果端口打开，则认为诊断成功。
HTTPGetAction： 对指定端口和路径上的容器IP地址执行HTTP Get请求。如果响应的状态码≥200且<400，则诊断认为是成功的。
注：http状态返回码
100：http请求发送成功
200：http返回成功
300：http转发成功
400：客户端错误如404
500：服务器端错误
1.5 检测结果
由kubelet对pod的状态进行检测
image.png
2 使用存活探针
2.1 存活探针案例
- 本案例采用execaction模式的存活探针。
- livenessProbe字段详细定义了存活
探针，包括：
Handler采用exec
使用方式是运行cat /tmp/healthy命令
探测延迟和探测周期是5秒钟。
apiVersion: v1
kind: Pod
metadata:
labels:
test: liveness
name: liveness-exec
spec:
containers:
- name: liveness
args:
- /bin/sh
- -c
- touch /tmp/healthy; sleep 30;rm -rf /tmp/healthy; sleep 600
image: busybox
livenessProbe:
exec:
command:
- cat
- /tmp/healthy
initialDelaySeconds: 5
periodSeconds: 5
2.2 Liveness探针流程
image.png
2.3 查看存活探针信息
- 使用describe命令查看pod信息，主要观察podid 是否每次在liveness检测发现失败后完成了自动的重启。
[root@k8s-master ~]# k describe pod liveness-exec
Name: liveness-exec
Namespace: default
Priority: 0
Node: k8s-node1/192.168.227.11
Start Time: Mon, 28 Feb 2022 13:21:45 +0800
Labels: test=liveness
Annotations: <none>
Status: Running
IP: 10.244.1.172
IPs: <none>
Containers:
liveness:
Container ID: docker://41452c228adc587f887cf89dde12055be0a9fff34e3563184d29652943ccd41b
Image: busybox
.........
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal Scheduled 109s default-scheduler Successfully assigned default/liveness-exec to k8s-node1
Warning Unhealthy 47s (x3 over 57s) kubelet Liveness probe failed: cat: can't open '/tmp/healthy': No such file or directory
Normal Killing 47s kubelet Container liveness failed liveness probe, will be restarted
Normal Pulling 17s (x2 over 108s) kubelet Pulling image "busybox"
Normal Pulled 1s (x2 over 92s) kubelet Successfully pulled image "busybox"
Normal Created 1s (x2 over 92s) kubelet Created container liveness
Normal Started 1s (x2 over 92s) kubelet Started container liveness
2.4 探针高级配置
- 在上一步骤中使用describe命令可以看到探针的一些策略
Liveness: exec [cat /tmp/healthy] delay=5s timeout=1s period=5s #success=1 #failure=3
- Delay=5s表示探针在容器启动后5秒开始进行第一次探测
- Timeout=1s表示容器必须在1秒内反馈信息给探针，否则视为失败。
- Period=5s表示每5秒探针进行一次探测。
- success=1表示探测连续成功1次，表示成功。
- failure=3表示探测连续失败3次，视为Pod处于failure状态，重启容器。
高级配置参数可以在配置参数时指定，以下为配置样例。实现的功能与之前配置的探针一致。
livenessProbe:
exec:
command:
- cat
- /tmp/healthy
initialDelaySeconds: 5
periodSeconds: 5
timeoutSeconds: 1
successThreshold: 1
failureThreshold: 3
2.5 存活探针 - HTTP
- HTTP方式的存活探针，通过get方法定期向容器发送http请求。方法中定义了请求路径、端口、请求头等信息。
- 由于探针仅在返回码≥200，小于400的情况下返回正常，10秒后探针检测失败，kubelet会重启容器。
apiVersion: v1
kind: Pod
metadata:
labels:
test: liveness
name: liveness-http
spec:
containers:
- name: liveness
image: mirrorgooglecontainers/liveness <===http的测试镜像
args:
- /server
livenessProbe:
httpGet:
path: /healthz
port: 8080
httpHeaders:
- name: X-Custom-Header
value: Awesome
initialDelaySeconds: 3
periodSeconds: 3
2.6 存活探针 - TCP
- TCP探针检测能否建立连接。实验中部署一个telnet服务，探针探测23端口。
- TCP探针参数与HTTP探针相似。
apiVersion: v1
kind: Pod
metadata:
labels:
app: httpd
name: liveness-tcp
spec:
containers:
- name: httpd
image: httpd
livenessProbe:
tcpSocket:
port: 8080
httpHeaders:
initialDelaySeconds: 10
periodSeconds: 10
存活探针 tcp探测失败示例
[root@k8s-master ~]# k apply -f /tmp/liveness-tcp.yaml
pod/liveness-tcp created
[root@k8s-master ~]# k get pod
NAME READY STATUS RESTARTS AGE
lablepod-fln79 0/1 Completed 2 18d
liveness-exec 1/1 Running 12 37m
liveness-tcp 0/1 ContainerCreating 0 3s
myapp-pod 1/1 Running 75 30d
mydep-65bbdb4c9f-bvwmp 1/1 Running 18 31d
mydep-65bbdb4c9f-sswdr 1/1 Running 19 31d
mydep-65bbdb4c9f-swgvz 1/1 Running 20 31d
mypod 0/1 ImagePullBackOff 0 30d
nginx-daemonset-966k2 1/1 Running 7 5d3h
nginx-daemonset-q6vh2 1/1 Running 5 5d3h
pi-8ggjj 0/1 Completed 0 5d3h
[root@k8s-master ~]# k get pod -w
NAME READY STATUS RESTARTS AGE
lablepod-fln79 0/1 Completed 2 18d
liveness-exec 1/1 Running 13 37m
liveness-tcp 0/1 ContainerCreating 0 13s
myapp-pod 1/1 Running 75 30d
mydep-65bbdb4c9f-bvwmp 1/1 Running 18 31d
mydep-65bbdb4c9f-sswdr 1/1 Running 19 31d
mydep-65bbdb4c9f-swgvz 1/1 Running 20 31d
mypod 0/1 ImagePullBackOff 0 30d
nginx-daemonset-966k2 1/1 Running 7 5d3h
nginx-daemonset-q6vh2 1/1 Running 5 5d3h
pi-8ggjj 0/1 Completed 0 5d3h
NAME AGE
liveness-tcp 26s
^C[root@k8s-master ~]# k get pod
NAME READY STATUS RESTARTS AGE
lablepod-fln79 0/1 Completed 2 18d
liveness-exec 1/1 Running 13 38m
liveness-tcp 1/1 Running 0 33s
myapp-pod 1/1 Running 75 30d
mydep-65bbdb4c9f-bvwmp 1/1 Running 18 31d
mydep-65bbdb4c9f-sswdr 1/1 Running 19 31d
mydep-65bbdb4c9f-swgvz 1/1 Running 20 31d
mypod 0/1 ImagePullBackOff 0 30d
nginx-daemonset-966k2 1/1 Running 7 5d3h
nginx-daemonset-q6vh2 1/1 Running 5 5d3h
pi-8ggjj 0/1 Completed 0 5d3h
[root@k8s-master ~]# k exec -it liveness-tcp /bin/bash
kubectl exec [POD] [COMMAND] is DEPRECATED and will be removed in a future version. Use kubectl exec [POD] -- [COMMAND] instead.
root@liveness-tcp:/usr/local/apache2# ls
bin build cgi-bin conf error htdocs icons include logs modules
root@liveness-tcp:/usr/local/apache2# cd conf
root@liveness-tcp:/usr/local/apache2/conf# ls
extra httpd.conf magic mime.types original
root@liveness-tcp:/usr/local/apache2/conf# cat httpd.conf | grep 80
#Listen 12.34.56.78:80
Listen 80
#ServerName www.example.com:80
root@liveness-tcp:/usr/local/apache2/conf# cat httpd.conf -n | grep 80
51 #Listen 12.34.56.78:80
52 Listen 80
80 #LoadModule authz_dbd_module modules/mod_authz_dbd.so
180 #LoadModule asis_module modules/mod_asis.so
241 #ServerName www.example.com:80
280
380 # directives as to Alias.
480 # MaxRanges: Maximum number of Ranges in a request before
root@liveness-tcp:/usr/local/apache2/conf# sed -i "52c Listen 8080"
sed: no input files
root@liveness-tcp:/usr/local/apache2/conf# sed -i "52c Listen 8080 httpd.conf"
sed: no input files
root@liveness-tcp:/usr/local/apache2/conf# sed -i "52c Listen 8080 " httpd.conf
root@liveness-tcp:/usr/local/apache2/conf# sed -i "241c ServerName localhost:8080" httpd.conf
root@liveness-tcp:/usr/local/apache2/conf# cat httpd.conf -n | grep 80
51 #Listen 12.34.56.78:80
52 Listen 8080
80 #LoadModule authz_dbd_module modules/mod_authz_dbd.so
180 #LoadModule asis_module modules/mod_asis.so
241 ServerName localhost:8080
280
380 # directives as to Alias.
480 # MaxRanges: Maximum number of Ranges in a request before
root@liveness-tcp:/usr/local/apache2/conf# httpd -k restart
root@liveness-tcp:/usr/local/apache2/conf# exit
exit
[root@k8s-master ~]# k get pod
NAME READY STATUS RESTARTS AGE
lablepod-fln79 0/1 Completed 2 18d
liveness-exec 1/1 Running 14 45m
liveness-tcp 1/1 Running 0 7m31s
myapp-pod 1/1 Running 76 30d
mydep-65bbdb4c9f-bvwmp 1/1 Running 18 31d
mydep-65bbdb4c9f-sswdr 1/1 Running 19 31d
mydep-65bbdb4c9f-swgvz 1/1 Running 20 31d
mypod 0/1 ImagePullBackOff 0 30d
nginx-daemonset-966k2 1/1 Running 7 5d3h
nginx-daemonset-q6vh2 1/1 Running 5 5d3h
pi-8ggjj 0/1 Completed 0 5d3h
[root@k8s-master ~]# k describe p
persistentvolumeclaims poddisruptionbudgets.policy podsecuritypolicies.extensions podtemplates
persistentvolumes pods podsecuritypolicies.policy priorityclasses.scheduling.k8s.io
[root@k8s-master ~]# k describe pods liveness-tcp
Name: liveness-tcp
Namespace: default
Priority: 0
Node: k8s-node2/192.168.227.12
Start Time: Mon, 28 Feb 2022 16:39:46 +0800
Labels: app=httpd
Annotations: <none>
Status: Running
IP: 10.244.2.228
IPs: <none>
Containers:
httpd:
Container ID: docker://1558d7fd06c0c938e02463e39f38636269991551ea72e86f9d34e80ea552cbc7
Image: httpd
Image ID: docker-pullable://httpd@sha256:0954cc1af252d824860b2c5dc0a10720af2b7a3d3435581ca788dff8480c7b32
Port: <none>
Host Port: <none>
State: Running
Started: Mon, 28 Feb 2022 16:40:11 +0800
Ready: True
Restart Count: 0
Liveness: tcp-socket :80 delay=10s timeout=1s period=10s #success=1 #failure=3
Environment: <none>
Mounts:
/var/run/secrets/kubernetes.io/serviceaccount from default-token-75t79 (ro)
Conditions:
Type Status
Initialized True
Ready True
ContainersReady True
PodScheduled True
Volumes:
default-token-75t79:
Type: Secret (a volume populated by a Secret)
SecretName: default-token-75t79
Optional: false
QoS Class: BestEffort
Node-Selectors: <none>
Tolerations: node.kubernetes.io/not-ready:NoExecute op=Exists for 300s
node.kubernetes.io/unreachable:NoExecute op=Exists for 300s
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal Scheduled 7m54s default-scheduler Successfully assigned default/liveness-tcp to k8s-node2
Normal Pulled 7m29s kubelet Successfully pulled image "httpd"
Normal Created 7m29s kubelet Created container httpd
Normal Started 7m29s kubelet Started container httpd
Warning Unhealthy 10s (x3 over 30s) kubelet Liveness probe failed: dial tcp 10.244.2.228:80: connect: connection refused
Normal Killing 10s kubelet Container httpd failed liveness probe, will be restarted
Normal Pulling 8s (x2 over 7m53s) kubelet Pulling image "httpd"
[root@k8s-master ~]# k get pod -w
NAME READY STATUS RESTARTS AGE
lablepod-fln79 0/1 Completed 2 18d
liveness-exec 1/1 Running 14 45m
liveness-tcp 1/1 Running 0 8m2s
myapp-pod 1/1 Running 76 30d
mydep-65bbdb4c9f-bvwmp 1/1 Running 18 31d
mydep-65bbdb4c9f-sswdr 1/1 Running 19 31d
mydep-65bbdb4c9f-swgvz 1/1 Running 20 31d
mypod 0/1 ImagePullBackOff 0 30d
nginx-daemonset-966k2 1/1 Running 7 5d3h
nginx-daemonset-q6vh2 1/1 Running 5 5d3h
pi-8ggjj 0/1 Completed 0 5d3h
NAME AGE
liveness-tcp 8m3s
liveness-exec 45m
^C[root@k8s-master ~]# k get pod
NAME READY STATUS RESTARTS AGE
lablepod-fln79 0/1 Completed 2 18d
liveness-exec 1/1 Running 15 46m
liveness-tcp 1/1 Running 1 8m32s
myapp-pod 1/1 Running 76 30d
mydep-65bbdb4c9f-bvwmp 1/1 Running 18 31d
mydep-65bbdb4c9f-sswdr 1/1 Running 19 31d
mydep-65bbdb4c9f-swgvz 1/1 Running 20 31d
mypod 0/1 ImagePullBackOff 0 30d
nginx-daemonset-966k2 1/1 Running 7 5d3h
nginx-daemonset-q6vh2 1/1 Running 5 5d3h
pi-8ggjj 0/1 Completed 0 5d3h
[root@k8s-master ~]# k describe pod liveness-tcp
Name: liveness-tcp
Namespace: default
Priority: 0
Node: k8s-node2/192.168.227.12
Start Time: Mon, 28 Feb 2022 16:39:46 +0800
Labels: app=httpd
Annotations: <none>
Status: Running
IP: 10.244.2.228
IPs: <none>
Containers:
httpd:
Container ID: docker://ba614058746d64b77ab003b8eea74d506e237660124e9bba2894c90cc97ddc13
Image: httpd
Image ID: docker-pullable://httpd@sha256:0954cc1af252d824860b2c5dc0a10720af2b7a3d3435581ca788dff8480c7b32
Port: <none>
Host Port: <none>
State: Running
Started: Mon, 28 Feb 2022 16:47:48 +0800
Last State: Terminated
Reason: Completed
Exit Code: 0
Started: Mon, 28 Feb 2022 16:40:11 +0800
Finished: Mon, 28 Feb 2022 16:47:31 +0800
Ready: True
Restart Count: 1
Liveness: tcp-socket :80 delay=10s timeout=1s period=10s #success=1 #failure=3
Environment: <none>
Mounts:
/var/run/secrets/kubernetes.io/serviceaccount from default-token-75t79 (ro)
Conditions:
Type Status
Initialized True
Ready True
ContainersReady True
PodScheduled True
Volumes:
default-token-75t79:
Type: Secret (a volume populated by a Secret)
SecretName: default-token-75t79
Optional: false
QoS Class: BestEffort
Node-Selectors: <none>
Tolerations: node.kubernetes.io/not-ready:NoExecute op=Exists for 300s
node.kubernetes.io/unreachable:NoExecute op=Exists for 300s
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal Scheduled 9m17s default-scheduler Successfully assigned default/liveness-tcp to k8s-node2
Warning Unhealthy 93s (x3 over 113s) kubelet Liveness probe failed: dial tcp 10.244.2.228:80: connect: connection refused
Normal Killing 93s kubelet Container httpd failed liveness probe, will be restarted
Normal Pulling 91s (x2 over 9m16s) kubelet Pulling image "httpd"
Normal Pulled 75s (x2 over 8m52s) kubelet Successfully pulled image "httpd"
Normal Created 75s (x2 over 8m52s) kubelet Created container httpd
Normal Started 75s (x2 over 8m52s) kubelet Started container httpd
[root@k8s-master ~]#
3 使用就绪探针
3.1 就绪探针
image.png
- Pod处于存活状态并不意味着可以提供服务，创建完成后通常需要进行诸如准备数据、安装和运行程序等步骤，才能对外提供服务。
- Liveness探针指示Pod是否处于存活状态，readiness探针则可指示容器是否已经一切准备就绪，可以对外提供服务。
3.2 存活探针和就绪探针对比
- 就 绪 探 针 与 存 活 探 针 一 致 ， 可 以 使 用 ExecAction ， TCPSocketAction ，HTTPGetAction三种方法。
-
就绪探针用于检测和显示Pod是否已经准备好对外提供业务。在实际使用场景中，就绪探针需要和业务绑定。
image.png
3.3 创建HTTP服务 （示例）
注意观察pod 和 endpoint的变化
1）创建httpd pod，加入exec 就绪探针
2） 创建service（endpoint）
操作：
1.整理环境，清理所有pod/deployment/deamonse/service
[root@k8s-master ~]# k get pod
NAME READY STATUS RESTARTS AGE
lablepod-fln79 0/1 Completed 2 18d
liveness-exec 1/1 Running 30 17h
liveness-tcp 1/1 Running 3 17h
myapp-pod 1/1 Running 78 30d
mydep-65bbdb4c9f-bvwmp 1/1 Running 20 31d
mydep-65bbdb4c9f-sswdr 1/1 Running 21 31d
mydep-65bbdb4c9f-swgvz 1/1 Running 22 31d
mypod 0/1 ImagePullBackOff 0 30d
nginx-daemonset-966k2 1/1 Running 9 5d20h
nginx-daemonset-q6vh2 1/1 Running 7 5d20h
pi-8ggjj 0/1 Completed 0 5d20h
[root@k8s-master ~]# k delete deployments. mydep
deployment.extensions "mydep" deleted
[root@k8s-master ~]# k get pod
NAME READY STATUS RESTARTS AGE
lablepod-fln79 0/1 Completed 2 18d
liveness-exec 1/1 Running 30 17h
liveness-tcp 1/1 Running 3 17h
myapp-pod 1/1 Running 78 30d
mydep-65bbdb4c9f-bvwmp 0/1 Terminating 20 31d
mydep-65bbdb4c9f-sswdr 0/1 Terminating 21 31d
mydep-65bbdb4c9f-swgvz 0/1 Terminating 22 31d
mypod 0/1 ImagePullBackOff 0 30d
nginx-daemonset-966k2 1/1 Running 9 5d20h
nginx-daemonset-q6vh2 1/1 Running 7 5d20h
pi-8ggjj 0/1 Completed 0 5d20h
[root@k8s-master ~]# k get deployments.
No resources found in default namespace.
[root@k8s-master ~]# k delete pod --all
pod "lablepod-fln79" deleted
pod "liveness-exec" deleted
pod "liveness-tcp" deleted
pod "myapp-pod" deleted
pod "mypod" deleted
pod "nginx-daemonset-966k2" deleted
pod "nginx-daemonset-q6vh2" deleted
pod "pi-8ggjj" deleted
[root@k8s-master ~]#
[root@k8s-master ~]# k get pod
NAME READY STATUS RESTARTS AGE
nginx-daemonset-s98tm 1/1 Running 0 36s
nginx-daemonset-t2w9n 1/1 Running 0 39s
[root@k8s-master ~]# k get jobs.batch
NAME COMPLETIONS DURATION AGE
lablepod 1/1 17h 18d
pi 1/1 84s 5d20h
[root@k8s-master ~]# k get deployments.
No resources found in default namespace.
[root@k8s-master ~]# k get deployments. -n kube-system
NAME READY UP-TO-DATE AVAILABLE AGE
coredns 2/2 2 2 32d
[root@k8s-master ~]# k describe pod nginx-daemonset-s98tm
Name: nginx-daemonset-s98tm
Namespace: default
Priority: 0
Node: k8s-node2/192.168.227.12
Start Time: Tue, 01 Mar 2022 09:49:44 +0800
Labels: app=nginx
controller-revision-hash=6dd86d77d
pod-template-generation=1
Annotations: <none>
Status: Running
IP: 10.244.2.239
IPs: <none>
Controlled By: DaemonSet/nginx-daemonset
Containers:
nginx:
Container ID: docker://580ddf981f401c8adb58ac9626ff0e8b660ed9b5f7bb51ec75c19fbbc7678726
Image: nginx:1.7.9
Image ID: docker-pullable://nginx@sha256:e3456c851a152494c3e4ff5fcc26f240206abac0c9d794affb40e0714846c451
Port: 80/TCP
Host Port: 0/TCP
State: Running
Started: Tue, 01 Mar 2022 09:49:45 +0800
Ready: True
Restart Count: 0
Environment: <none>
Mounts:
/var/run/secrets/kubernetes.io/serviceaccount from default-token-75t79 (ro)
Conditions:
Type Status
Initialized True
Ready True
ContainersReady True
PodScheduled True
Volumes:
default-token-75t79:
Type: Secret (a volume populated by a Secret)
SecretName: default-token-75t79
Optional: false
QoS Class: BestEffort
Node-Selectors: <none>
Tolerations: node.kubernetes.io/disk-pressure:NoSchedule op=Exists
node.kubernetes.io/memory-pressure:NoSchedule op=Exists
node.kubernetes.io/not-ready:NoExecute op=Exists
node.kubernetes.io/pid-pressure:NoSchedule op=Exists
node.kubernetes.io/unreachable:NoExecute op=Exists
node.kubernetes.io/unschedulable:NoSchedule op=Exists
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal Scheduled 2m2s default-scheduler Successfully assigned default/nginx-daemonset-s98tm to k8s-node2
Normal Pulled 2m2s kubelet Container image "nginx:1.7.9" already present on machine
Normal Created 2m1s kubelet Created container nginx
Normal Started 2m1s kubelet Started container nginx
[root@k8s-master ~]# k get svc
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 32d
nginx-svc NodePort 10.100.16.243 <none> 8080:30144/TCP 10d
[root@k8s-master ~]# k get pod
NAME READY STATUS RESTARTS AGE
nginx-daemonset-s98tm 1/1 Running 0 2m52s
nginx-daemonset-t2w9n 1/1 Running 0 2m55s
[root@k8s-master ~]# k delete daemonsets. nginx-daemonset
daemonset.extensions "nginx-daemonset" deleted
[root@k8s-master ~]# k get pod
No resources found in default namespace.
[root@k8s-master ~]#
[root@k8s-master ~]# k get svc
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 32d
nginx-svc NodePort 10.100.16.243 <none> 8080:30144/TCP 10d
[root@k8s-master ~]# k delete svc nginx-svc
service "nginx-svc" deleted
[root@k8s-master ~]# k get svc
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 32d
[root@k8s-master ~]#
2 创建deployment ，创建service，删除掉某一个httpd的index.html文件观察pod状态和endpoint的范围变化，修复后（touch index.html）后再次观察pod状态和endpoint范围，预期结果恢复
[root@k8s-master tmp]# cat httpdeploy.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
name: httpd-deployment
spec:
replicas: 3
selector:
matchLabels:
app: httpd
template:
metadata:
labels:
app: httpd
spec:
containers:
- name: httpd
image: httpd
ports:
- containerPort: 80
readinessProbe:
exec:
command:
- cat
- /usr/local/apache2/htdocs/index.html
initialDelaySeconds: 5
periodSeconds: 5
[root@k8s-master tmp]# k get pod
NAME READY STATUS RESTARTS AGE
httpd-deployment-859778b7b6-5rwrn 1/1 Running 0 2m9s
httpd-deployment-859778b7b6-fg8vj 1/1 Running 0 2m9s
httpd-deployment-859778b7b6-hfw9t 1/1 Running 0 2m9s
[root@k8s-master tmp]# vim httpsvc.yaml
[root@k8s-master tmp]# k apply -f httpsvc.yaml
service/httpd-svc created
[root@k8s-master tmp]# k get svc
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
httpd-svc ClusterIP 10.98.110.166 <none> 8080/TCP 5s
kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 33d
[root@k8s-master tmp]# k get endpoints httpd-svc
NAME ENDPOINTS AGE
httpd-svc 10.244.1.184:80,10.244.1.185:80,10.244.2.240:80 23s
[root@k8s-master tmp]# k get pod -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
httpd-deployment-859778b7b6-5rwrn 1/1 Running 0 5m57s 10.244.2.240 k8s-node2 <none> <none>
httpd-deployment-859778b7b6-fg8vj 1/1 Running 0 5m57s 10.244.1.185 k8s-node1 <none> <none>
httpd-deployment-859778b7b6-hfw9t 1/1 Running 0 5m57s 10.244.1.184 k8s-node1 <none> <none>
[root@k8s-master tmp]# k exec -it httpd-deployment-859778b7b6-5rwrn /bin/bash
kubectl exec [POD] [COMMAND] is DEPRECATED and will be removed in a future version. Use kubectl exec [POD] -- [COMMAND] instead.
root@httpd-deployment-859778b7b6-5rwrn:/usr/local/apache2# ls
bin build cgi-bin conf error htdocs icons include logs modules
root@httpd-deployment-859778b7b6-5rwrn:/usr/local/apache2# cd htdoc
bash: cd: htdoc: No such file or directory
root@httpd-deployment-859778b7b6-5rwrn:/usr/local/apache2# ls
bin build cgi-bin conf error htdocs icons include logs modules
root@httpd-deployment-859778b7b6-5rwrn:/usr/local/apache2# cd htdocs
root@httpd-deployment-859778b7b6-5rwrn:/usr/local/apache2/htdocs# ll
bash: ll: command not found
root@httpd-deployment-859778b7b6-5rwrn:/usr/local/apache2/htdocs# ls
index.html
root@httpd-deployment-859778b7b6-5rwrn:/usr/local/apache2/htdocs# rm index.html
root@httpd-deployment-859778b7b6-5rwrn:/usr/local/apache2/htdocs# exit
exit
[root@k8s-master tmp]# cat /tmp/httpdeploy.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
name: httpd-deployment
spec:
replicas: 3
selector:
matchLabels:
app: httpd
template:
metadata:
labels:
app: httpd
spec:
containers:
- name: httpd
image: httpd
ports:
- containerPort: 80
readinessProbe:
exec:
command:
- cat
- /usr/local/apache2/htdocs/index.html
initialDelaySeconds: 5
periodSeconds: 5
[root@k8s-master tmp]# sleep 10
[root@k8s-master tmp]# k get pods
NAME READY STATUS RESTARTS AGE
httpd-deployment-859778b7b6-5rwrn 0/1 Running 0 8m53s
httpd-deployment-859778b7b6-fg8vj 1/1 Running 0 8m53s
httpd-deployment-859778b7b6-hfw9t 1/1 Running 0 8m53s
[root@k8s-master tmp]# k get pods -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
httpd-deployment-859778b7b6-5rwrn 0/1 Running 0 9m5s 10.244.2.240 k8s-node2 <none> <none>
httpd-deployment-859778b7b6-fg8vj 1/1 Running 0 9m5s 10.244.1.185 k8s-node1 <none> <none>
httpd-deployment-859778b7b6-hfw9t 1/1 Running 0 9m5s 10.244.1.184 k8s-node1 <none> <none>
[root@k8s-master tmp]# k get endpoints httpd-svc
NAME ENDPOINTS AGE
httpd-svc 10.244.1.184:80,10.244.1.185:80 4m10s
[root@k8s-master tmp]# k exec -it httpd-deployment-859778b7b6-5rwrn
error: you must specify at least one command for the container
[root@k8s-master tmp]# k exec -it httpd-deployment-859778b7b6-5rwrn -- /bin/bash
root@httpd-deployment-859778b7b6-5rwrn:/usr/local/apache2# ls
bin build cgi-bin conf error htdocs icons include logs modules
root@httpd-deployment-859778b7b6-5rwrn:/usr/local/apache2# cd htdocs/
root@httpd-deployment-859778b7b6-5rwrn:/usr/local/apache2/htdocs# ls
root@httpd-deployment-859778b7b6-5rwrn:/usr/local/apache2/htdocs# touch index.html
root@httpd-deployment-859778b7b6-5rwrn:/usr/local/apache2/htdocs# sleep 5
root@httpd-deployment-859778b7b6-5rwrn:/usr/local/apache2/htdocs# k get pod -o wide
bash: k: command not found
root@httpd-deployment-859778b7b6-5rwrn:/usr/local/apache2/htdocs# exit
exit
command terminated with exit code 127
[root@k8s-master tmp]# k get pod -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
httpd-deployment-859778b7b6-5rwrn 1/1 Running 0 11m 10.244.2.240 k8s-node2 <none> <none>
httpd-deployment-859778b7b6-fg8vj 1/1 Running 0 11m 10.244.1.185 k8s-node1 <none> <none>
httpd-deployment-859778b7b6-hfw9t 1/1 Running 0 11m 10.244.1.184 k8s-node1 <none> <none>
[root@k8s-master tmp]# k get endpoints httpd-svc
NAME ENDPOINTS AGE
httpd-svc 10.244.1.184:80,10.244.1.185:80,10.244.2.240:80 6m35s
[root@k8s-master tmp]#
