文章目录
一、kubernetes基本概念
Pod：k8s的最小部署单位，一组容器的集合
Development：最常见的控制器，用于更高级别部署和管理Pod
Service：为一组Pod提供负载均衡，对外提供统一的访问入口
Label： 标签，附加到某个资源上，用于关联对象，查询和筛选
NameSpace：命名空间，将对象逻辑上隔离，也有利于权限控制
kubernetes将资源对象逻辑上隔离，从而形成了多个虚拟集群，更方便管理。
kubectl get namespace
NAME STATUS AGE
calico-apiserver Active 12d
calico-system Active 12d
default Active 12d
kube-node-lease Active 12d
kube-public Active 12d
kube-system Active 12d
kubernetes-dashboard Active 12d
tigera-operator Active 12d
default ： 默认命名空间
kube-system： k8s系统方面的命名空间
kube-public ： 公开的命名空间，谁都可以访问
kube-node-least ： k8s内部命名空间
两种方法指定资源所属的命名空间：
命令行加-n选项；yaml资源元数据里指定namespace字段；
二、集群资源监控
查看API资源对象及缩写
[root@k8s-master ~]# kubectl api-resources
NAME SHORTNAMES APIVERSION NAMESPACED KIND
bindings v1 true Binding
componentstatuses cs v1 false ComponentStatus
configmaps cm v1 true ConfigMap
endpoints ep v1 true Endpoints
events ev v1 true Event
limitranges limits v1 true LimitRange
namespaces ns v1 false Namespace
nodes no v1 false Node
persistentvolumeclaims pvc v1 true PersistentVolumeClaim
persistentvolumes pv v1 false PersistentVolume
pods po v1 true Pod
......
资源对象的简写可以提高我们在使用k8s过程中的输入效率，但是对初学者来说不容易理解，可以采用配置kubectl自动补全的方式
查看master组件状态
这条命令会显示master节点的主要组件：etcd，controller-manager，scheduler的工作状态
[root@k8s-master ~]#kubectl get cs
[root@k8s-master ~]# kubectl get componentstatuses
Warning: v1 ComponentStatus is deprecated in v1.19+
NAME STATUS MESSAGE ERROR
etcd-0 Healthy ok
controller-manager Healthy ok
scheduler Healthy ok
查看集群节点状态
这条命令可以查到当前集群master节点和node节点的工作状态
kubectl get nodes
[root@k8s-master ~]# kubectl get nodes
NAME STATUS ROLES AGE VERSION
k8s-master Ready control-plane 13d v1.28.0
k8s-node1 Ready <none> 13d v1.28.0
k8s-node2 Ready <none> 13d v1.28.0
查看资源详情
kubectl describe <资源类型> <资源名称>
查看一个deployment的详细信息
[root@k8s-master ~]# kubectl get deployment -n test
NAME READY UP-TO-DATE AVAILABLE AGE
nginx 3/3 3 3 5d17h
nginx-test 1/1 1 1 11d
[root@k8s-master ~]# kubectl describe deployment nginx -n test
Name: nginx
Namespace: test
CreationTimestamp: Wed, 10 Jul 2024 17:04:14 +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:
nginx:
Image: nginx:1.16
Port: <none>
Host Port: <none>
Environment: <none>
Mounts: <none>
Volumes: <none>
Conditions:
Type Status Reason
---- ------ ------
Progressing True NewReplicaSetAvailable
Available True MinimumReplicasAvailable
OldReplicaSets: <none>
NewReplicaSet: nginx-85bfcd86d5 (3/3 replicas created)
Events: <none>
查看一个pod的详细信息
[root@k8s-master ~]# kubectl get pods -n test
NAME READY STATUS RESTARTS AGE
nginx-85bfcd86d5-5dl44 1/1 Running 3 (4d12h ago) 5d17h
nginx-85bfcd86d5-7kjvt 1/1 Running 3 (4d12h ago) 5d17h
nginx-85bfcd86d5-fltkh 1/1 Running 3 (4d12h ago) 5d17h
nginx-test-d87b84fb7-lcvg7 1/1 Running 6 (4d12h ago) 11d
[root@k8s-master ~]# kubectl describe pods nginx-test-d87b84fb7-lcvg7 -n test
Name: nginx-test-d87b84fb7-lcvg7
Namespace: test
Priority: 0
Service Account: default
Node: k8s-node1/192.168.3.11
Start Time: Thu, 04 Jul 2024 10:45:20 +0800
Labels: k8s-app=nginx-test
pod-template-hash=d87b84fb7
Annotations: cni.projectcalico.org/containerID: 5d84c8a34dd067d8b77205c1abfd7eef58ddf67571c39e807e862457bc400c5f
cni.projectcalico.org/podIP: 10.244.36.97/32
cni.projectcalico.org/podIPs: 10.244.36.97/32
Status: Running
IP: 10.244.36.97
IPs:
IP: 10.244.36.97
Controlled By: ReplicaSet/nginx-test-d87b84fb7
Containers:
nginx-test:
Container ID: docker://1a0bdae7e63c45454024fd0e66fdbc615d832a3bd82ba5a1f27315c75ce63ec7
Image: nginx:1.23
Image ID: docker-pullable://nginx@sha256:f5747a42e3adcb3168049d63278d7251d91185bb5111d2563d58729a5c9179b0
Port: <none>
Host Port: <none>
State: Running
Started: Tue, 16 Jul 2024 10:04:31 +0800
Last State: Terminated
Reason: Completed
Exit Code: 0
Started: Thu, 11 Jul 2024 19:23:30 +0800
Finished: Thu, 11 Jul 2024 22:18:17 +0800
Ready: True
Restart Count: 6
Environment: <none>
Mounts:
/var/run/secrets/kubernetes.io/serviceaccount from kube-api-access-9nsbn (ro)
Conditions:
Type Status
Initialized True
Ready True
ContainersReady True
PodScheduled True
Volumes:
kube-api-access-9nsbn:
Type: Projected (a volume that contains injected data from multiple sources)
TokenExpirationSeconds: 3607
ConfigMapName: kube-root-ca.crt
ConfigMapOptional: <nil>
DownwardAPI: true
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
---- ------ ---- ---- -------
Warning NodeNotReady 4d13h node-controller Node is not ready
Normal SandboxChanged 33m (x2 over 33m) kubelet Pod sandbox changed, it will be killed and re-created.
Normal Pulled 32m kubelet Container image "nginx:1.23" already present on machine
Normal Created 32m kubelet Created container nginx-test
Normal Started 32m kubelet Started container nginx-test
查看service的详细信息
[root@k8s-master ~]# kubectl get service -n test
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
nginx-test ClusterIP 10.96.255.119 <none> 80/TCP 11d
[root@k8s-master ~]# kubectl describe service nginx-test -n test
Name: nginx-test
Namespace: test
Labels: k8s-app=nginx-test
Annotations: <none>
Selector: k8s-app=nginx-test
Type: ClusterIP
IP Family Policy: SingleStack
IP Families: IPv4
IP: 10.96.255.119
IPs: 10.96.255.119
Port: tcp-80-80-rqfqj 80/TCP
TargetPort: 80/TCP
Endpoints: 10.244.36.97:80
Session Affinity: None
Events: <none>
查看资源信息
kubectl get <资源类型> <资源名称>
-o wide 显示详情
-o yaml 将配置输出为yaml格式
-n namespace 查看对应命名空间
资源监控服务
资源监控服务由metric-server服务提供数据，而这个服务默认没有安装，还需要手动部署一下。
metric server 是一个集群范围的资源使用情况的数据聚合器，作为一个应用部署在集群中。metric server从每个节点上的kubelet API 收集指标，通过kubernetes聚合器注册在Master APIserver中，为集群提供Node、 Pods资源利用率指标。
metric组件的yaml文件可以在github拉取，国内网络不允许，需要合适的加速器
查看node资源消耗
kubectl top node <node name>
[root@k8s-master ~]# kubectl top nodes
NAME CPU(cores) CPU% MEMORY(bytes) MEMORY%
k8s-master 292m 14% 1154Mi 67%
k8s-node1 169m 8% 706Mi 41%
k8s-node2 220m 11% 883Mi 51%
查看Pod资源消耗
kubectl top pod <pod name>
[root@k8s-master ~]# kubectl top pod nginx-test-d87b84fb7-lcvg7 -n test
NAME CPU(cores) MEMORY(bytes)
nginx-test-d87b84fb7-lcvg7 0m 12Mi
k8s日志
kubelet日志：
到对应的宿主机查看，使用
journalctl -u kubelet
pod组件日志：
kubectl logs <资源名称> -n <命名空间>
查看pod日志
[root@k8s-master ~]# kubectl logs nginx-test-d87b84fb7-lcvg7 -n test
/docker-entrypoint.sh: /docker-entrypoint.d/ is not empty, will attempt to perform configuration
/docker-entrypoint.sh: Looking for shell scripts in /docker-entrypoint.d/
/docker-entrypoint.sh: Launching /docker-entrypoint.d/10-listen-on-ipv6-by-default.sh
10-listen-on-ipv6-by-default.sh: info: Getting the checksum of /etc/nginx/conf.d/default.conf
10-listen-on-ipv6-by-default.sh: info: Enabled listen on IPv6 in /etc/nginx/conf.d/default.conf
/docker-entrypoint.sh: Launching /docker-entrypoint.d/20-envsubst-on-templates.sh
/docker-entrypoint.sh: Launching /docker-entrypoint.d/30-tune-worker-processes.sh
/docker-entrypoint.sh: Configuration complete; ready for start up
2024/07/16 02:04:32 [notice] 1#1: using the "epoll" event method
2024/07/16 02:04:32 [notice] 1#1: nginx/1.23.4
2024/07/16 02:04:32 [notice] 1#1: built by gcc 10.2.1 20210110 (Debian 10.2.1-6)
2024/07/16 02:04:32 [notice] 1#1: OS: Linux 3.10.0-1160.71.1.el7.x86_64
2024/07/16 02:04:32 [notice] 1#1: getrlimit(RLIMIT_NOFILE): 1048576:1048576
2024/07/16 02:04:32 [notice] 1#1: start worker processes
2024/07/16 02:04:32 [notice] 1#1: start worker process 29
2024/07/16 02:04:32 [notice] 1#1: start worker process 30
系统日志：
/var/log/messages
容器的标准输出日志：
kubectl logs <Pod名称>
kubectl logs -f <Pod名称> #-f可以动态显示日志
kubectl exec -it <Pod名称> -- bash #进入pod内部查看标准输出日志
