文章目录
-
-
- [3. 实战入门](#3. 实战入门)
-
- [3.1 Namespace](#3.1 Namespace)
-
- [3.1.1 测试两个不同的名称空间之间的 Pod 是否连通性](#3.1.1 测试两个不同的名称空间之间的 Pod 是否连通性)
- [3.2 Pod](#3.2 Pod)
- [3.3 Label](#3.3 Label)
- [3.4 Deployment](#3.4 Deployment)
- [3.5 Service](#3.5 Service)
-
3. 实战入门
本章节将介绍如何在kubernetes集群中部署一个nginx服务，并且能够对其进行访问。
3.1 Namespace
Namespace是kubernetes系统中的一种非常重要资源，它的主要作用是用来实现多套环境的资源隔离 或者多租户的资源隔离。
默认情况下，kubernetes集群中的所有的Pod都是可以相互访问的。但是在实际中，可能不想让两个Pod之间进行互相的访问，那此时就可以将两个Pod划分到不同的namespace下。kubernetes通过将集群内部的资源分配到不同的Namespace中，可以形成逻辑上的"组"，以方便不同的组的资源进行隔离使用和管理。
可以通过kubernetes的授权机制，将不同的namespace交给不同租户进行管理，这样就实现了多租户的资源隔离。此时还能结合kubernetes的资源配额机制，限定不同租户能占用的资源，例如CPU使用量、内存使用量等等，来实现租户可用资源的管理。
3.1.1 测试两个不同的名称空间之间的 Pod 是否连通性
elixir
[root@k8s-master ~]# mkdir manifest
[root@k8s-master ~]# cd manifest
[root@k8s-master manifest]# pwd
/root/manifest
[root@k8s-master manifest]# cat nginx-pod.yaml
apiVersion: v1
kind: Namespace
metadata:
name: dev
---
apiVersion: v1
kind: Pod
metadata:
name: nginx-pod
namespace: dev
spec:
containers:
- name: nginx-containers
image: busybox:latest
command: ["/bin/sleep","6000"]
---
apiVersion: v1
kind: Pod
metadata:
name: apache # 不指定名称空间就是跑在默认的
spec:
containers:
- name: httpd
image: busybox:latest
command: ["/bin/sleep","6000"]
[root@k8s-master manifest]# kubectl get -n default pod
NAME READY STATUS RESTARTS AGE
apache 1/1 Running 0 19s
[root@k8s-master manifest]# kubectl get -n dev pod
NAME READY STATUS RESTARTS AGE
nginx-pod 1/1 Running 0 25s
# 进入 Pod 的 apache
[root@k8s-master manifest]# kubectl exec apache -it -- sh
/ # ls
bin dev etc home lib lib64 proc root sys tmp usr var
/ # ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: eth0@if7: <BROADCAST,MULTICAST,UP,LOWER_UP,M-DOWN> mtu 1450 qdisc noqueue
link/ether 5e:19:37:e6:3e:5a brd ff:ff:ff:ff:ff:ff
inet 10.244.2.12/24 brd 10.244.2.255 scope global eth0
valid_lft forever preferred_lft forever
inet6 fe80::5c19:37ff:fee6:3e5a/64 scope link
valid_lft forever preferred_lft forever
/ #
# 进入 Pod 的nginx-pod
[root@k8s-master manifest]# kubectl exec nginx-pod -i -t -n dev -- sh
/ #
/ # ls
bin dev etc home lib lib64 proc root sys tmp usr var
/ # ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: eth0@if7: <BROADCAST,MULTICAST,UP,LOWER_UP,M-DOWN> mtu 1450 qdisc noqueue
link/ether 66:d3:72:81:17:00 brd ff:ff:ff:ff:ff:ff
inet 10.244.1.16/24 brd 10.244.1.255 scope global eth0
valid_lft forever preferred_lft forever
inet6 fe80::64d3:72ff:fe81:1700/64 scope link
valid_lft forever preferred_lft forever
/ # ping 10.244.2.12
PING 10.244.2.12 (10.244.2.12): 56 data bytes
64 bytes from 10.244.2.12: seq=0 ttl=62 time=1.170 ms
64 bytes from 10.244.2.12: seq=1 ttl=62 time=0.397 ms
64 bytes from 10.244.2.12: seq=2 ttl=62 time=0.743 mskubernetes在集群启动之后，会默认创建几个 namespace
shell
[root@k8s-master ~]# kubectl get namespace
NAME STATUS AGE
default Active 45h # 所有未指定Namespace的对象都会被分配在default命名空间
kube-node-lease Active 45h # 集群节点之间的心跳维护，v1.13开始引入
kube-public Active 45h # 此命名空间下的资源可以被所有人访问（包括未认证用户）
kube-system Active 45h # 所有由Kubernetes系统创建的资源都处于这个命名空间下面来看namespace资源的具体操作：
**查看 **
shell
# 1 查看所有的ns 命令：kubectl get ns
[root@k8s-master ~]# kubectl get ns
NAME STATUS AGE
default Active 45h
kube-node-lease Active 45h
kube-public Active 45h
kube-system Active 45h
# 2 查看指定的ns 命令：kubectl get ns ns名称
[root@k8s-master ~]# kubectl get ns default
NAME STATUS AGE
default Active 45h
# 3 指定输出格式 命令：kubectl get ns ns名称 -o 格式参数
# kubernetes支持的格式有很多，比较常见的是wide、json、yaml
[root@k8s-master ~]# kubectl get ns default -o yaml
apiVersion: v1
kind: Namespace
metadata:
creationTimestamp: "2023-01-08T02:04:00Z"
labels:
kubernetes.io/metadata.name: default
name: default
resourceVersion: "191"
uid: ed84973a-29b4-4286-ae46-d8df5c113334
spec:
finalizers:
- kubernetes
status:
phase: Active
[root@k8s-master ~]#
# 4 查看ns详情 命令：kubectl describe ns ns名称
[root@k8s-master ~]# kubectl describe ns default 或 kubectl describe pod apache
Name: default
Labels: kubernetes.io/metadata.name=default
Annotations: <none>
Status: Active # Active 命名空间正在使用中 Terminating 正在删除命名空间
No resource quota. # Resource Quota 针对namespace做的资源限制
No LimitRange resource. # LimitRange针对namespace中的每个组件做的资源限制
[root@k8s-master inventory]# pwd
/root/inventory
[root@k8s-master inventory]#
[root@k8s-master inventory]# kubectl describe pod apache
Name: apache // Pod 名字
Namespace: default // 在那个名称空间运行
Priority: 0
Service Account: default
Node: k8s-node1/192.168.192.4 // 在那台node节点上运行
Start Time: Fri, 28 Jul 2023 13:23:17 +0800 // 启动时间
Labels: <none>
Annotations: <none>
Status: Running // 现在的状态是Runing
IP: 10.244.1.15 // IP 地址
IPs:
IP: 10.244.1.15
Containers:
httpd:
Container ID: containerd://b7eeb63f0cb390657ad84dd42aa42acd74d56088e17a48b04b1633e1e12ab57a
Image: httpd // 运行那个镜像名
Image ID: // 镜像ID docker.io/library/httpd@sha256:33a91a69517f0642b3e8be5cc8d12f8c1ae245728a83947bfc098376be63c15e
Port: <none>
Host Port: <none>
State: Running
Started: Fri, 28 Jul 2023 13:25:14 +0800
Ready: True
Restart Count: 0
Environment: <none>
Mounts:
/var/run/secrets/kubernetes.io/serviceaccount from kube-api-access-xmsjx (ro)
Conditions:
Type Status
Initialized True
Ready True
ContainersReady True
PodScheduled True
Volumes:
kube-api-access-xmsjx:
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: <none>
[root@k8s-master inventory]# 创建
shell
# 创建namespace(创建名称空间)
[root@k8s-master ~]# kubectl create ns dev
namespace/dev created删除
shell
# 删除namespace(创建名称空间)
[root@k8s-master ~]# kubectl delete ns dev
namespace "dev" deleted配置方式
首先准备一个yaml文件：ns-dev.yaml
yaml
# 创建一个最简单的名称空间
apiVersion: v1
kind: Namespace
metadata:
name: dev然后就可以执行对应的创建和删除命令了：
创建：kubectl create -f ns-dev.yaml
删除：kubectl delete -f ns-dev.yaml
3.2 Pod
Pod是kubernetes集群进行管理的最小单元，程序要运行必须部署在容器中，而容器必须存在于Pod中。
Pod可以认为是容器的封装，一个Pod中可以存在一个或者多个容器。
测试一个 Pod 跑多个容器
shell
[root@k8s-master manifest]# cat testpodrun.yaml
apiVersion: v1
kind: Pod
metadata:
name: nginx-pod
spec:
containers:
- name: nginx-containers
image: httpd:latest
- name: nginx
image: nginx:latest
[root@k8s-master inventory]# kubectl apply -f test_pod_run.yaml
pod/nginx-pod created
[root@k8s-master ~]# kubectl get pod nginx-pod
NAME READY STATUS RESTARTS AGE
nginx-pod 1/2 CrashLoopBackOff 6 (3m49s ago) 10m
# 使用describe 命令查看nginx-pod 在做些什么事
[root@k8s-master manifest]# kubectl describe pod nginx-pod
kubernetes在集群启动之后，集群中的各个组件也都是以Pod方式运行的。可以通过下面命令查看：
shell
[root@k8s-master ~]# kubectl get pod -n kube-system
NAMESPACE NAME READY STATUS RESTARTS AGE
kube-system coredns-6955765f44-68g6v 1/1 Running 0 2d1h
kube-system coredns-6955765f44-cs5r8 1/1 Running 0 2d1h
kube-system etcd-master 1/1 Running 0 2d1h
kube-system kube-apiserver-master 1/1 Running 0 2d1h
kube-system kube-controller-manager-master 1/1 Running 0 2d1h
kube-system kube-flannel-ds-amd64-47r25 1/1 Running 0 2d1h
kube-system kube-flannel-ds-amd64-ls5lh 1/1 Running 0 2d1h
kube-system kube-proxy-685tk 1/1 Running 0 2d1h
kube-system kube-proxy-87spt 1/1 Running 0 2d1h
kube-system kube-scheduler-master 1/1 Running 0 2d1h创建并运行
kubernetes没有提供单独运行Pod的命令，都是通过Pod控制器来实现的
shell
# 命令格式： kubectl run (pod控制器名称) [参数]
# --image 指定Pod的镜像
# --port 指定端口
# --namespace 指定namespace
[root@k8s-master ~]# kubectl create namespace dev
namespace/dev created
[root@k8s-master ~]# kubectl get namespace
NAME STATUS AGE
default Active 204d
dev Active 7s
kube-flannel Active 204d
kube-node-lease Active 204d
kube-public Active 204d
kube-system Active 204d
[root@k8s-master ~]#
[root@k8s-master ~]# kubectl run nginx --image=nginx:latest --port=80 --namespace dev
pod/nginx created查看pod信息
shell
# 查看Pod基本信息
[root@k8s-master ~]# kubectl get pods -n dev
NAME READY STATUS RESTARTS AGE
nginx 1/1 Running 0 29s
# 查看Pod的详细信息
[root@k8s-master ~]# kubectl describe pod nginx -n dev
Name: nginx // Pod 名字
Namespace: dev // 名称空间名字
Priority: 0
Service Account: default
Node: k8s-node1/192.168.192.4
Start Time: Mon, 31 Jul 2023 15:21:53 +0800
Labels: run=nginx
Annotations: <none>
Status: Running // 表示在运行
IP: 10.244.1.18
IPs:
IP: 10.244.1.18
Containers:
nginx:
Container ID: containerd://a9607020f2f7170b104af0f35ec36f3b0f740a1abe9b5c543b114f145b6e0494
Image: nginx:latest
Image ID: docker.io/library/nginx@sha256:67f9a4f10d147a6e04629340e6493c9703300ca23a2f7f3aa56fe615d75d31ca
Port: 80/TCP
Host Port: 0/TCP
State: Running
Started: Mon, 31 Jul 2023 15:21:56 +0800
Ready: True
Restart Count: 0
Environment: <none>
Mounts:
/var/run/secrets/kubernetes.io/serviceaccount from kube-api-access-726tm (ro)
Conditions:
Type Status
Initialized True
Ready True
ContainersReady True
PodScheduled True
Volumes:
kube-api-access-726tm:
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
---- ------ ---- ---- -------
Normal Scheduled 2m default-scheduler Successfully assigned dev/nginx to k8s-node1
Normal Pulling 119s kubelet Pulling image "nginx:latest"
Normal Pulled 117s kubelet Successfully pulled image "nginx:latest" in 2.32545784s (2.325463331s including waiting)
Normal Created 117s kubelet Created container nginx
Normal Started 117s kubelet Started container nginx
[root@k8s-master ~]# 访问Pod
shell
# 获取podIP
[root@k8s-master ~]# kubectl get pods -n dev -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
nginx 1/1 Running 0 3m38s 10.244.1.18 k8s-node1 <none> <none>
[root@k8s-master ~]#
#访问POD
[root@k8s-master ~]# curl 10.244.1.18
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>
html { color-scheme: light dark; }
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>
[root@k8s-master ~]# 删除指定Pod
shell
[root@k8s-master ~]# kubectl delete pod nginx -n dev // 删除Pod
pod "nginx" deleted
[root@k8s-master ~]#
[root@k8s-master ~]# kubectl get pods -n dev
No resources found in dev namespace.
[root@k8s-master ~]#
[root@k8s-master ~]# kubectl get ns
NAME STATUS AGE
default Active 204d
dev Active 6m12s
kube-flannel Active 204d
kube-node-lease Active 204d
kube-public Active 204d
kube-system Active 204d
[root@k8s-master ~]#
[root@k8s-master ~]# kubectl delete namespace dev // 删除名称空间
namespace "dev" deleted
[root@k8s-master ~]#
[root@k8s-master ~]# kubectl get ns
NAME STATUS AGE
default Active 204d
kube-flannel Active 204d
kube-node-lease Active 204d
kube-public Active 204d
kube-system Active 204d
[root@k8s-master ~]# 配置操作
创建一个pod-nginx.yaml，内容如下：
yaml
[root@k8s-master inventory]# pwd
/root/inventory
[root@k8s-master inventory]# cat pod-nginx.yaml
apiVersion: v1
kind: Namespace
metadata:
name: dev
---
apiVersion: v1
kind: Pod
metadata:
name: nginx
namespace: dev
spec:
containers:
- image: nginx:latest
name: pod
ports:
- name: nginx-port
containerPort: 80
protocol: TCP
[root@k8s-master inventory]#
[root@k8s-master inventory]# kubectl apply -f pod-nginx.yaml
namespace/dev created
pod/nginx created
[root@k8s-master inventory]#
[root@k8s-master inventory]# kubectl get pod -n dev
NAME READY STATUS RESTARTS AGE
nginx 1/1 Running 0 14s
[root@k8s-master inventory]#
[root@k8s-master inventory]# kubectl get -f pod-nginx.yaml
NAME STATUS AGE
namespace/dev Active 6m47s
NAME READY STATUS RESTARTS AGE
pod/nginx 1/1 Running 0 6m47s
[root@k8s-master inventory]# 然后就可以执行对应的创建和删除命令了：
创建：kubectl create -f pod-nginx.yaml
删除：kubectl delete -f pod-nginx.yaml
3.3 Label
Label是kubernetes系统中的一个重要概念。它的作用就是在资源上添加标识，用来对它们进行区分和选择。
Label的特点：
- 一个Label会以key/value键值对的形式附加到各种对象上，如Node、Pod、Service等等
- 一个资源对象可以定义任意数量的Label ，同一个Label也可以被添加到任意数量的资源对象上去
- Label通常在资源对象定义时确定，当然也可以在对象创建后动态添加或者删除
可以通过Label实现资源的多维度分组，以便灵活、方便地进行资源分配、调度、配置、部署等管理工作。
一些常用的Label 示例如下：
- 版本标签："version":"release", "version":"stable"...
- 环境标签："environment":"dev"，"environment":"test"，"environment":"prod"
- 架构标签："tier":"frontend"，"tier":"backend"
标签定义完毕之后，还要考虑到标签的选择，这就要使用到Label Selector，即：
Label用于给某个资源对象定义标识
Label Selector用于查询和筛选拥有某些标签的资源对象
当前有两种Label Selector：
-
基于等式的Label Selector
name = slave: 选择所有包含Label中key="name"且value="slave"的对象
env != production: 选择所有包括Label中的key="env"且value不等于"production"的对象
-
基于集合的Label Selector
name in (master, slave): 选择所有包含Label中的key="name"且value="master"或"slave"的对象
name not in (frontend): 选择所有包含Label中的key="name"且value不等于"frontend"的对象
标签的选择条件可以使用多个，此时将多个Label Selector进行组合，使用逗号","进行分隔即可。例如：
name=slave，env!=production
name not in (frontend)，env!=production
命令方式
shell
[root@k8s-master ~]# kubectl get pods -n dev // 查看名称空间dev中有哪些Pod
NAME READY STATUS RESTARTS AGE
nginx 1/1 Running 1 (39m ago) 4d17h
[root@k8s-master ~]#
# 1.查看是否已有标签
[root@k8s-master ~]# kubectl describe -n dev pods nginx | grep -i labels
Labels: <none>
[root@k8s-master ~]#
# 2.查看是否已有标签
[root@k8s-master ~]# kubectl get pods nginx -n dev --show-labels
NAME READY STATUS RESTARTS AGE LABELS
nginx 1/1 Running 1 (42m ago) 4d17h <none> // 标签
[root@k8s-master ~]#
# 为pod资源打标签
[root@k8s-master ~]# kubectl label pod nginx app=test -n dev
pod/nginx labeled
[root@k8s-master ~]# kubectl describe -n dev pod nginx | grep -i labels
Labels: app=test
[root@k8s-master ~]#
[root@k8s-master ~]# kubectl label -n dev pod nginx app=test1
error: 'app' already has a value (test), and --overwrite is false
// 需要带 [--overwrite] 不然会报错
# 为pod资源更新标签
[root@k8s-master ~]# kubectl label pod nginx app=test1 -n dev --overwrite
pod/nginx labeled
# 查看标签
[root@k8s-master ~]# kubectl get -n dev pod nginx --show-labels
NAME READY STATUS RESTARTS AGE LABELS
nginx 1/1 Running 1 (49m ago) 4d17h app=test1
[root@k8s-master ~]#
# 筛选标签
[root@k8s-master ~]# kubectl get -n dev pod -l app=test1 --show-labels
NAME READY STATUS RESTARTS AGE LABELS
nginx 1/1 Running 1 (52m ago) 4d17h app=test1
[root@k8s-master ~]#
# 取反
[root@k8s-master ~]# kubectl get pod -n dev -l app!=test1 --show-labels
No resources found in dev namespace.
#删除标签
[root@k8s-master ~]# kubectl label pod nginx -n dev app-
pod/nginx unlabeled
[root@k8s-master ~]#
[root@k8s-master ~]# kubectl get pod nginx -n dev --show-labels
NAME READY STATUS RESTARTS AGE LABELS
nginx 1/1 Running 1 (54m ago) 4d17h <none>
[root@k8s-master ~]# 配置方式
elixir
[root@k8s-master manifest]# cat test.yaml
apiVersion: v1
kind: Pod
metadata:
labels:
version: web
name: httpd
namespace: default
spec:
containers:
- image: httpd:latest
imagePullPolicy: IfNotPresent
name: httpd
ports:
- containerPort: 80
name: httpd-port
hostPort: 8080
protocol: TCP
[root@k8s-master manifest]# kubectl apply -f test.yaml
pod/httpd created
[root@k8s-master manifest]# kubectl get pod httpd --show-labels
NAME READY STATUS RESTARTS AGE LABELS
httpd 1/1 Running 0 101s version=web然后就可以执行对应的更新命令了：kubectl apply -f pod-nginx.yaml
3.4 Deployment
在kubernetes中，Pod是最小的控制单元，但是kubernetes很少直接控制Pod，一般都是通过Pod控制器来完成的。Pod控制器用于pod的管理，确保pod资源符合预期的状态，当pod的资源出现故障时，会尝试进行重启或重建pod。
在kubernetes中Pod控制器的种类有很多，本章节只介绍一种：Deployment。
命令操作
shell
# 命令格式: kubectl create deployment 名称 [参数]
# --image 指定pod的镜像
# --port 指定端口
# --replicas 指定创建pod数量
# --namespace 指定namespace
[root@k8s-master ~]# kubectl get namespace
NAME STATUS AGE
default Active 209d
dev Active 4d21h
kube-flannel Active 209d
kube-node-lease Active 209d
kube-public Active 209d
kube-system Active 209d
[root@k8s-master ~]#
[root@k8s-master ~]# kubectl create namespace test // 创建一个名称空间
namespace/test created
[root@k8s-master ~]# kubectl get ns test // 指定查看名称空间
NAME STATUS AGE
test Active 18s
[root@k8s-master ~]#
# 查看[名称空间test] namespace，以yaml格式展示结果
[root@k8s-master ~]# kubectl get ns test -o yaml
apiVersion: v1
kind: Namespace
metadata:
creationTimestamp: "2023-08-05T05:34:26Z"
labels:
kubernetes.io/metadata.name: test
name: test
resourceVersion: "1093635"
uid: f9ddabdc-d52f-4952-ae39-4fa93cc2751c
spec:
finalizers:
- kubernetes
status:
phase: Active
[root@k8s-master ~]# kubectl get ns test --show-labels
NAME STATUS AGE LABELS
test Active 23m kubernetes.io/metadata.name=test
[root@k8s-master ~]#
[root@k8s-master ~]# kubectl create deployment nginx --image=nginx:latest --port=80 --replicas=4 -n test
deployment.apps/nginx created
# 查看创建的Pod
[root@k8s-master ~]# kubectl get -n test pods
NAME READY STATUS RESTARTS AGE
my-deploy-6648745bcc-7ttcf 1/1 Running 0 3m3s
my-deploy-6648745bcc-vm4vg 1/1 Running 0 3m3s
my-deploy-6648745bcc-x87ng 1/1 Running 0 3m3s
[root@k8s-master ~]#
[root@k8s-master ~]# kubectl get -n test pods -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
my-deploy-6648745bcc-7ttcf 1/1 Running 0 3m38s 10.244.1.22 k8s-node1 <none> <none>
my-deploy-6648745bcc-vm4vg 1/1 Running 0 3m38s 10.244.2.16 k8s-node2 <none> <none>
my-deploy-6648745bcc-x87ng 1/1 Running 0 3m38s 10.244.2.15 k8s-node2 <none> <none>
[root@k8s-master ~]#
# 查看deployment的信息
[root@k8s-master ~]# kubectl get deploy -n test -o wide
NAME READY UP-TO-DATE AVAILABLE AGE CONTAINERS IMAGES SELECTOR
my-deploy 3/3 3 3 4m38s nginx nginx:latest app=my-deploy
[root@k8s-master ~]#
# UP-TO-DATE：成功升级的副本数量
# AVAILABLE：可用副本的数量
# 加参数 --show-labels 查看标签
[root@k8s-master ~]# kubectl get deploy -n test --show-labels
NAME READY UP-TO-DATE AVAILABLE AGE LABELS
my-deploy 3/3 3 3 5m53s app=my-deploy
[root@k8s-master ~]# kubectl get pods -n test --show-labels
NAME READY STATUS RESTARTS AGE LABELS
my-deploy-6648745bcc-7ttcf 1/1 Running 0 6m33s app=my-deploy,pod-template-hash=6648745bcc
my-deploy-6648745bcc-vm4vg 1/1 Running 0 6m33s app=my-deploy,pod-template-hash=6648745bcc
my-deploy-6648745bcc-x87ng 1/1 Running 0 6m33s app=my-deploy,pod-template-hash=6648745bcc
[root@k8s-master ~]#
# 查看deployment的详细信息
[root@k8s-master ~]# kubectl describe deployment my-deploy -n test
Name: my-deploy
Namespace: test
CreationTimestamp: Sat, 05 Aug 2023 13:42:53 +0800
Labels: app=my-deploy
Annotations: deployment.kubernetes.io/revision: 1
Selector: app=my-deploy
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=my-deploy
Containers:
nginx:
Image: nginx:latest
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: my-deploy-6648745bcc (3/3 replicas created)
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal ScalingReplicaSet 8m58s deployment-controller Scaled up replica set my-deploy-6648745bcc to 3
[root@k8s-master ~]#
# 查看deployment，以yaml 格式展示结果 查看某个pod,以yaml格式展示结果
[root@k8s-master ~]# kubectl get deployment my-deploy -o yaml -n test
apiVersion: apps/v1
kind: Deployment
metadata:
annotations:
deployment.kubernetes.io/revision: "1"
creationTimestamp: "2023-08-05T05:42:53Z"
generation: 1
labels:
app: my-deploy
name: my-deploy
namespace: test
resourceVersion: "1094451"
uid: cf361c04-0c57-46f1-be24-4fc93680c493
spec:
progressDeadlineSeconds: 600
replicas: 3
revisionHistoryLimit: 10
selector:
matchLabels:
app: my-deploy
strategy:
rollingUpdate:
maxSurge: 25%
maxUnavailable: 25%
type: RollingUpdate
template:
metadata:
creationTimestamp: null
labels:
app: my-deploy
spec:
containers:
- image: nginx:latest
imagePullPolicy: Always
name: nginx
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: "2023-08-05T05:43:00Z"
lastUpdateTime: "2023-08-05T05:43:00Z"
message: Deployment has minimum availability.
reason: MinimumReplicasAvailable
status: "True"
type: Available
- lastTransitionTime: "2023-08-05T05:42:53Z"
lastUpdateTime: "2023-08-05T05:43:00Z"
message: ReplicaSet "my-deploy-6648745bcc" has successfully progressed.
reason: NewReplicaSetAvailable
status: "True"
type: Progressing
observedGeneration: 1
readyReplicas: 3
replicas: 3
updatedReplicas: 3
[root@k8s-master ~]#
// 如果要写yaml格式的创建名称空间[namespace]或者是deployment、pod的都是可以手动先创建出来然后执行[kubectl get pod pod_name -o yaml]展示出来后，可以照着展示出来的内容写。
# 删除
[root@k8s-master ~]# kubectl delete -n test deployment my-deploy
deployment.apps "my-deploy" deleted
[root@k8s-master ~]# 配置操作
创建一个deploy-nginx.yaml，内容如下：
shell
[root@k8s-master ~]# cd inventory/
[root@k8s-master inventory]#
[root@k8s-master inventory]# cat deploy-nginx.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
labels:
app: my-deploy-nginx
name: my-deploy-nginx // Pod 名字叫做：my-deploy-nginx
namespace: test
spec:
replicas: 4 // 在这个Pod下运行4个容器
selector:
matchLabels:
app: my-deploy
template:
metadata:
labels:
app: my-deploy
spec:
containers:
- image: nginx:latest
imagePullPolicy: IfNotPresent // 如果镜像存在本地，不拉取，如果没有存在本地着拉取
name: nginx-containers // Pod 中容器的名称
ports:
- containerPort: 80
protocol: TCP
[root@k8s-master inventory]#
[root@k8s-master inventory]# kubectl apply -f deploy-nginx.yaml
deployment.apps/my-deploy-nginx created
[root@k8s-master inventory]#
[root@k8s-master inventory]# kubectl get -f deploy-nginx.yaml
NAME READY UP-TO-DATE AVAILABLE AGE
my-deploy-nginx 4/4 4 4 17m
[root@k8s-master inventory]# kubectl get -f deploy-nginx.yaml -o wide
NAME READY UP-TO-DATE AVAILABLE AGE CONTAINERS IMAGES SELECTOR
my-deploy-nginx 4/4 4 4 17m nginx-containers nginx:latest app=my-deploy
[root@k8s-master inventory]#
[root@k8s-master inventory]# kubectl get pods -n test
NAME READY STATUS RESTARTS AGE
my-deploy-nginx-6bdd87fd6d-c5sxz 1/1 Running 0 18m
my-deploy-nginx-6bdd87fd6d-cnjrd 1/1 Running 0 18m
my-deploy-nginx-6bdd87fd6d-v8b8z 1/1 Running 0 18m
my-deploy-nginx-6bdd87fd6d-wd25q 1/1 Running 0 18m
[root@k8s-master inventory]#
# 查看deployment的标签[--show-labels]
[root@k8s-master inventory]# kubectl get deploy -n test --show-labels
NAME READY UP-TO-DATE AVAILABLE AGE LABELS
my-deploy-nginx 4/4 4 4 19m app=my-deploy-nginx
[root@k8s-master inventory]#
# 查看Pod的标签[--show-labels]
[root@k8s-master inventory]# kubectl get pods -n test --show-labels
NAME READY STATUS RESTARTS AGE LABELS
my-deploy-nginx-6bdd87fd6d-c5sxz 1/1 Running 0 20m app=my-deploy,pod-template-hash=6bdd87fd6d
my-deploy-nginx-6bdd87fd6d-cnjrd 1/1 Running 0 20m app=my-deploy,pod-template-hash=6bdd87fd6d
my-deploy-nginx-6bdd87fd6d-v8b8z 1/1 Running 0 20m app=my-deploy,pod-template-hash=6bdd87fd6d
my-deploy-nginx-6bdd87fd6d-wd25q 1/1 Running 0 20m app=my-deploy,pod-template-hash=6bdd87fd6d
[root@k8s-master inventory]#
[root@k8s-master ~]# kubectl get -n test pods -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
my-deploy-nginx-6bdd87fd6d-c5sxz 1/1 Running 0 29m 10.244.1.24 k8s-node1 <none> <none>
my-deploy-nginx-6bdd87fd6d-cnjrd 1/1 Running 0 29m 10.244.2.18 k8s-node2 <none> <none>
my-deploy-nginx-6bdd87fd6d-v8b8z 1/1 Running 0 29m 10.244.2.17 k8s-node2 <none> <none>
my-deploy-nginx-6bdd87fd6d-wd25q 1/1 Running 0 29m 10.244.1.23 k8s-node1 <none> <none>
[root@k8s-master ~]#
[root@k8s-master ~]# curl 10.244.2.17 // 只能在内部访问
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>
html { color-scheme: light dark; }
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>
[root@k8s-master ~]# 可以执行对应的创建和删除命令了：
创建：kubectl create -f deploy-nginx.yaml
删除：kubectl delete -f deploy-nginx.yaml
3.5 Service
通过上一章节的学习，已经能够利用Deployment创建一组Pod来提供具有高可用性的服务。
虽然每个Pod都会分配一个单独的Pod IP，然而却存在如下两问题：
- Pod IP 会随着Pod的重建产生变化
- Pod IP 仅仅是集群内可见的虚拟IP，外部无法访问
这样对于访问这个服务带来了难度。因此，kubernetes设计了Service来解决这个问题。
Service可以看作是一组同类Pod对外的访问接口。借助Service，应用可以方便地实现服务发现和负载均衡。
操作一：创建集群内部可访问的Service
shell
# 在上面已经使用yaml格式创建了4个容器，使用deployment
[root@k8s-master ~]# kubectl get pods -n test
NAME READY STATUS RESTARTS AGE
my-deploy-nginx-6bdd87fd6d-c5sxz 1/1 Running 0 87m
my-deploy-nginx-6bdd87fd6d-cnjrd 1/1 Running 0 87m
my-deploy-nginx-6bdd87fd6d-v8b8z 1/1 Running 0 87m
my-deploy-nginx-6bdd87fd6d-wd25q 1/1 Running 0 87m
[root@k8s-master ~]#
[root@k8s-master ~]# kubectl get deployment -n test // deployment名为：my-deploy-nginx
NAME READY UP-TO-DATE AVAILABLE AGE
my-deploy-nginx 4/4 4 4 90m
[root@k8s-master ~]#
# 默认的名称空间[default]
[root@k8s-master ~]# kubectl get service // 查看当前有那些service服务
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 209d // 系统自带的
[root@k8s-master ~]#
# 查看指定的名称空间[-n 指定查看那个的名称空间]
[root@k8s-master ~]# kubectl get -n test service
No resources found in dev namespace.
[root@k8s-master ~]#
# 暴露Service
[root@k8s-master ~]# kubectl expose deployment my-deploy-nginx --name=svc-my-deploy-nginx --port=80 --target-port=80 --type=ClusterIP -n test
service/svc-my-deploy-nginx exposed
[root@k8s-master ~]#
# 查看service
[root@k8s-master ~]# kubectl get -n test service
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
svc-my-deploy-nginx ClusterIP 10.103.51.241 <none> 80/TCP 3m24s
[root@k8s-master ~]#
# 这里产生了一个CLUSTER-IP，这就是service的IP，在Service的生命周期中，这个地址是不会变动的
# 可以通过这个IP访问当前service对应的POD
[root@k8s-master ~]# curl 10.103.51.241:80
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>
html { color-scheme: light dark; }
body { width: 35em; margin: 0 auto;
font-family: Tahoma, Verdana, Arial, sans-serif; }
</style>
</head>
<body>
<h1>Welcome to nginx!</h1> # 欢迎使用nginx!
<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>
[root@k8s-master ~]#操作二：创建集群外部也可访问的Service
shell
# 上面创建的Service的type类型为ClusterIP，这个ip地址只用集群内部可访问
# 如果需要创建外部也可以访问的Service，需要修改type为NodePort
[root@k8s-master ~]# kubectl expose deployment my-deploy-nginx --name=svc-nginx --port=80 --target-port=80 --type=NodePort -n test
service/svc-nginx exposed
[root@k8s-master ~]#
# 此时查看，会发现出现了NodePort类型的Service，而且有一对Port（80:30044/TC）
[root@k8s-master ~]# kubectl get -n test service
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
svc-my-deploy-nginx ClusterIP 10.103.51.241 <none> 80/TCP 14m
svc-nginx NodePort 10.103.113.161 <none> 80:30044/TCP 9s
[root@k8s-master ~]#
# 接下来就可以通过集群外的主机访问 节点IP:30044 访问服务了
# 例如在的电脑主机上通过浏览器访问下面的地址
http://192.168.192.4:30044/ 或者 http://192.168.192.5:30044/ 
删除Service
shell
[root@k8s-master ~]# kubectl delete -n test service svc-my-deploy-nginx svc-nginx
service "svc-my-deploy-nginx" deleted
service "svc-nginx" deleted
[root@k8s-master ~]# kubectl get -n test service
No resources found in test namespace.
[root@k8s-master ~]# 配置方式
创建一个svc-nginx.yaml，内容如下：
shell
[root@k8s-master inventory]# kubectl get pods -n test --show-labels
NAME READY STATUS RESTARTS AGE LABELS
my-deploy-nginx-6bdd87fd6d-c5sxz 1/1 Running 0 3h1m app=my-deploy,pod-template-hash=6bdd87fd6d
my-deploy-nginx-6bdd87fd6d-cnjrd 1/1 Running 0 3h1m app=my-deploy,pod-template-hash=6bdd87fd6d
my-deploy-nginx-6bdd87fd6d-v8b8z 1/1 Running 0 3h1m app=my-deploy,pod-template-hash=6bdd87fd6d
my-deploy-nginx-6bdd87fd6d-wd25q 1/1 Running 0 3h1m app=my-deploy,pod-template-hash=6bdd87fd6d
[root@k8s-master inventory]#
[root@k8s-master ~]# cd inventory/
[root@k8s-master inventory]#
[root@k8s-master inventory]# cat svc-nginx.yaml
apiVersion: v1
kind: Service
metadata:
name: svc-nginx
namespace: test
spec:
clusterIP: 10.109.179.231 # 固定service的内网IP。也可以不写它自动创建一个IP出来
ports:
- port: 80
protocol: TCP
targetPort: 80
selector:
app: my-deploy # 指定容器标签my-deploy
type: NodePort
[root@k8s-master inventory]#
[root@k8s-master inventory]# kubectl apply -f svc-nginx.yaml
service/svc-nginx created
[root@k8s-master inventory]#
[root@k8s-master inventory]# kubectl get svc -n test
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
svc-nginx NodePort 10.109.179.231 <none> 80:30726/TCP 9s
[root@k8s-master inventory]#
[root@k8s-master inventory]# curl 10.109.179.231
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>
html { color-scheme: light dark; }
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>
[root@k8s-master inventory]#
# 接下来就可以通过集群外的主机访问 节点IP:30726 访问服务了
# 例如在的电脑主机上通过浏览器访问下面的地址
http://192.168.192.4:30726可以执行对应的创建和删除命令了：
创建：kubectl create -f svc-nginx.yaml
删除：kubectl delete -f svc-nginx.yaml
yaml
apiVersion: v1
kind: Service
metadata:
name: svc-nginx
namespace: test
spec:
clusterIP: 10.109.179.231
ports:
- port: 80
protocol: TCP
targetPort: 80
selector:
app: my-deploy
type: ClusterIP 小结
至此，已经掌握了Namespace、Pod、Deployment、Service资源的基本操作，有了这些操作，就可以在kubernetes集群中实现一个服务的简单部署和访问了，但是如果想要更好的使用kubernetes，就需要深入学习这几种资源的细节和原理。