1、Kubernetes基本概览
由于Kubernetes每年三四个版本发布，官网永远是最权威的；话不多说，先提供官网地址：https://kubernetes.io/zh/docs/tutorials/kubernetes-basics/
1.1、集群与节点
- 查看master主键角色：
1 [root@master1 ~]# kubectl get componentstatuses # 也可以使用简写： kubectl get cs
2 Warning: v1 ComponentStatus is deprecated in v1.19+
3 NAME STATUS MESSAGE ERROR
4 scheduler Unhealthy Get "http://127.0.0.1:10251/healthz": dial tcp 127.0.0.1:10251: connect: connection refused
5 controller-manager Healthy ok
6 etcd-0 Healthy {"health":"true","reason":""}
7 [root@master1 ~]#
- 查看node节点列表：
1 [root@master1 ~]# kubectl get nodes -o wide # 也可以使用简写： kubectl get no 2 NAME STATUS ROLES AGE VERSION INTERNAL-IP EXTERNAL-IP OS-IMAGE KERNEL-VERSION CONTAINER-RUNTIME 3 master1 Ready control-plane,master 44h v1.22.2 192.168.1.66 <none> CentOS Linux 8 4.18.0-240.el8.x86_64 docker://20.10.8 4 node1 Ready <none> 44h v1.22.2 192.168.1.77 <none> CentOS Linux 8 4.18.0-240.el8.x86_64 docker://20.10.8 5 node2 Ready <none> 44h v1.22.2 192.168.1.88 <none> CentOS Linux 8 4.18.0-240.el8.x86_64 docker://20.10.8 6 [root@master1 ~]#
- 查看node节点详情：
1 [root@master1 ~]# kubectl describe nodes node2
2 Name: node2
3 Roles: <none>
4 Labels: beta.kubernetes.io/arch=amd64
5 beta.kubernetes.io/os=linux
6 kubernetes.io/arch=amd64
7 kubernetes.io/hostname=node2
8 kubernetes.io/os=linux
9 Annotations: flannel.alpha.coreos.com/backend-data: {"VNI":1,"VtepMAC":"be:68:4a:f9:ac:de"}
10 flannel.alpha.coreos.com/backend-type: vxlan
11 flannel.alpha.coreos.com/kube-subnet-manager: true
12 flannel.alpha.coreos.com/public-ip: 192.168.1.88
13 kubeadm.alpha.kubernetes.io/cri-socket: /var/run/dockershim.sock
14 node.alpha.kubernetes.io/ttl: 0
15 volumes.kubernetes.io/controller-managed-attach-detach: true
16 CreationTimestamp: Fri, 01 Oct 2021 06:59:33 -0400
17 Taints: <none>
18 Unschedulable: false
19 Lease:
20 HolderIdentity: node2
21 AcquireTime: <unset>
22 RenewTime: Sun, 03 Oct 2021 03:45:59 -0400
23 Conditions:
24 Type Status LastHeartbeatTime LastTransitionTime Reason Message
25 ---- ------ ----------------- ------------------ ------ -------
26 NetworkUnavailable False Sun, 03 Oct 2021 02:47:43 -0400 Sun, 03 Oct 2021 02:47:43 -0400 FlannelIsUp Flannel is running on this node
27 MemoryPressure False Sun, 03 Oct 2021 03:42:49 -0400 Fri, 01 Oct 2021 06:59:33 -0400 KubeletHasSufficientMemory kubelet has sufficient memory available
28 DiskPressure False Sun, 03 Oct 2021 03:42:49 -0400 Fri, 01 Oct 2021 06:59:33 -0400 KubeletHasNoDiskPressure kubelet has no disk pressure
29 PIDPressure False Sun, 03 Oct 2021 03:42:49 -0400 Fri, 01 Oct 2021 06:59:33 -0400 KubeletHasSufficientPID kubelet has sufficient PID available
30 Ready True Sun, 03 Oct 2021 03:42:49 -0400 Fri, 01 Oct 2021 07:03:54 -0400 KubeletReady kubelet is posting ready status
31 Addresses: # 节点的IP地址和主机名
32 InternalIP: 192.168.1.88
33 Hostname: node2
34 Capacity: # 节点总资源
35 cpu: 2
36 ephemeral-storage: 17398Mi
37 hugepages-1Gi: 0
38 hugepages-2Mi: 0
39 memory: 1996236Ki
40 pods: 110
41 Allocatable: # 节点可以分配的资源
42 cpu: 2
43 ephemeral-storage: 16418812697
44 hugepages-1Gi: 0
45 hugepages-2Mi: 0
46 memory: 1893836Ki
47 pods: 110
48 System Info: # 系统的相关信息
49 Machine ID: fd49b99f63534bc9a6544ff2f1d68ef5
50 System UUID: 2a454d56-033c-c61e-c4f8-37b171f12218
51 Boot ID: c66bb70c-b358-4d60-b6f2-9f2cb49dad2e
52 Kernel Version: 4.18.0-240.el8.x86_64
53 OS Image: CentOS Linux 8
54 Operating System: linux
55 Architecture: amd64
56 Container Runtime Version: docker://20.10.8
57 Kubelet Version: v1.22.2 # kubelet版本
58 Kube-Proxy Version: v1.22.2 # kube-proxy版本
59 PodCIDR: 172.16.2.0/24 # pod网络
60 PodCIDRs: 172.16.2.0/24
61 Non-terminated Pods: (2 in total) # 当前节点已经运行pod情况，及每个pod占用的资源情况
62 Namespace Name CPU Requests CPU Limits Memory Requests Memory Limits Age
63 --------- ---- ------------ ---------- --------------- ------------- ---
64 kube-system kube-flannel-ds-zp785 100m (5%) 100m (5%) 50Mi (2%) 50Mi (2%) 44h
65 kube-system kube-proxy-s6ndp 0 (0%) 0 (0%) 0 (0%) 0 (0%) 53m
66 Allocated resources: # 已分配资源情况
67 (Total limits may be over 100 percent, i.e., overcommitted.)
68 Resource Requests Limits
69 -------- -------- ------
70 cpu 100m (5%) 100m (5%)
71 memory 50Mi (2%) 50Mi (2%)
72 ephemeral-storage 0 (0%) 0 (0%)
73 hugepages-1Gi 0 (0%) 0 (0%)
74 hugepages-2Mi 0 (0%) 0 (0%)
75 Events:
76 Type Reason Age From Message
77 ---- ------ ---- ---- -------
78 Normal Starting 44h kubelet Starting kubelet.
79 Normal NodeHasSufficientMemory 44h (x2 over 44h) kubelet Node node2 status is now: NodeHasSufficientMemory
80 Normal NodeHasNoDiskPressure 44h (x2 over 44h) kubelet Node node2 status is now: NodeHasNoDiskPressure
81 Normal NodeHasSufficientPID 44h (x2 over 44h) kubelet Node node2 status is now: NodeHasSufficientPID
82 Normal NodeAllocatableEnforced 44h kubelet Updated Node Allocatable limit across pods
83 Normal NodeReady 44h kubelet Node node2 status is now: NodeReady
84 [root@master1 ~]#