k8s实战入门
1. Namespace
1.1 介绍
-
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。
-
测试：kubernetes集群中的所有的Pod都是可以相互访问的
进入容器：kubectl exec --help
Usage:
kubectl exec (POD | TYPE/NAME) [-c CONTAINER] [flags] -- COMMAND [args...] [options]
[root@k8s-master ~]# kubectl get pods
NAME READY STATUS RESTARTS AGE
apache-855464645-4zxf2 1/1 Running 2 (115m ago) 22h
[root@k8s-master ~]# kubectl exec apache-855464645-4zxf2 -it -- bash
root@apache-855464645-4zxf2:/usr/local/apache2# ls
bin cgi-bin error icons logs
build conf htdocs include modules
root@apache-855464645-4zxf2:/usr/local/apache2#
查看sleep在busybody里的位置
[root@k8s-node2 ~]# docker run -it --rm busybox
Unable to find image 'busybox:latest' locally
latest: Pulling from library/busybox
5cc84ad355aa: Pull complete
Digest: sha256:5acba83a746c7608ed544dc1533b87c737a0b0fb730301639a0179f9344b1678
Status: Downloaded newer image for busybox:latest
/ # which slep
/ # which sleep
/bin/sleep
/ # exit
[root@k8s-node2 ~]#
在容器里执行命令方法：
[root@k8s-master ~]# kubectl explain pods.spec.containers
command: ["/bin/sleep","6000"]
[root@k8s-master ~]# cd manifest/
[root@k8s-master manifest]# ls
nginxpod.yml
[root@k8s-master manifest]# cp nginxpod.yml test.yml
[root@k8s-master manifest]# vim test.yml
[root@k8s-master manifest]# cat test.yml
apiVersion: v1
kind: Namespace
metadata:
name: dev
---
apiVersion: v1
kind: Pod
metadata:
name: nginx
namespace: dev
spec:
containers:
- name: nginx-containers
image: busybox
command: ["/bin/sleep","6000"]
---
apiVersion: v1
kind: Pod
metadata:
name: apache
spec:
containers:
- name: httpd
image: busybox
command: ["/bin/sleep","6000"]
[root@k8s-master manifest]#
运行命令
[root@k8s-master manifest]# kubectl apply -f test.yml
namespace/dev created
pod/nginx created
pod/apache created
[root@k8s-master manifest]# kubectl get -f test.yml
NAME STATUS AGE
namespace/dev Active 17s
NAME READY STATUS RESTARTS AGE
pod/nginx 1/1 Running 0 17s
pod/apache 1/1 Running 0 17s
[root@k8s-master manifest]#
[root@k8s-master manifest]# kubectl exec apache -it -- sh
/ # ls
bin dev etc home 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
3: eth0@if18: <BROADCAST,MULTICAST,UP,LOWER_UP,M-DOWN> mtu 1450 qdisc noqueue
link/ether be:ab:f1:70:78:47 brd ff:ff:ff:ff:ff:ff
inet 10.244.2.19/24 brd 10.244.2.255 scope global eth0
valid_lft forever preferred_lft forever
inet6 fe80::bcab:f1ff:fe70:7847/64 scope link
valid_lft forever preferred_lft forever
/ #
/ # ping 10.244.2.18
PING 10.244.2.18 (10.244.2.18): 56 data bytes
64 bytes from 10.244.2.18: seq=0 ttl=64 time=0.117 ms
64 bytes from 10.244.2.18: seq=1 ttl=64 time=1.426 ms
64 bytes from 10.244.2.18: seq=2 ttl=64 time=0.078 ms
^C
--- 10.244.2.18 ping statistics ---
3 packets transmitted, 3 packets received, 0% packet loss
round-trip min/avg/max = 0.078/0.540/1.426 ms
[root@k8s-master ~]# kubectl exec nginx -itn dev -- sh
/ # 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
3: eth0@if17: <BROADCAST,MULTICAST,UP,LOWER_UP,M-DOWN> mtu 1450 qdisc noqueue
link/ether ca:ef:b8:81:d1:b5 brd ff:ff:ff:ff:ff:ff
inet 10.244.2.18/24 brd 10.244.2.255 scope global eth0
valid_lft forever preferred_lft forever
inet6 fe80::c8ef:b8ff:fe81:d1b5/64 scope link
valid_lft forever preferred_lft forever
/ # ping 10.244.2.19
PING 10.244.2.19 (10.244.2.19): 56 data bytes
64 bytes from 10.244.2.19: seq=0 ttl=64 time=0.065 ms
64 bytes from 10.244.2.19: seq=1 ttl=64 time=0.060 ms
^C
--- 10.244.2.19 ping statistics ---
2 packets transmitted, 2 packets received, 0% packet loss
round-trip min/avg/max = 0.060/0.062/0.065 ms
/ #
是相通的
-
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。
- kubernetes在集群启动之后，会默认创建几个namespace
[root@k8s-master ~]# kubectl get ns
NAME STATUS AGE
default Active 31h # 所有未指定Namespace的对象都会被分配在default命名空间
kube-flannel Active 30h
kube-node-lease Active 31h # 集群节点之间的心跳维护，v1.13开始引入
kube-public Active 31h # 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 31h # 所有由Kubernetes系统创建的资源都处于这个命名空间
[root@k8s-master ~]#
1.2 namespace资源的具体操作：
- 查看
# 1 查看所有的ns 命令：kubectl get ns
[root@k8s-master ~]# kubectl get ns
NAME STATUS AGE
default Active 31h
kube-flannel Active 30h
kube-node-lease Active 31h
kube-public Active 31h
kube-system Active 31h
# 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 31h
[root@k8s-master ~]#
# 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: "2022-09-06T05:32:38Z"//创建时间戳，可写可不写
labels://标签，可写可不写
kubernetes.io/metadata.name: default
name: default
resourceVersion: "191"
uid: f32a553e-48db-4bc0-ba7a-f3a999dca024
spec://可写可不写
finalizers:
- kubernetes
status:
phase: Active//默认是激活的
[root@k8s-master ~]#
# 4 查看ns详情 命令：kubectl describe ns ns名称//[root@k8s-master ~]# kubectl describe pods apache-855464645-4zxf2
[root@k8s-master ~]# kubectl describe ns default
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
# ResourceQuota 针对namespace做的资源限制
# LimitRange针对namespace中的每个组件做的资源限制
No resource quota.
No LimitRange resource.
[root@k8s-master ~]#
- 创建
# 创建namespace
[root@k8s-master ~]# kubectl create ns dev
namespace/dev created
[root@k8s-master ~]# kubectl get ns
NAME STATUS AGE
default Active 31h
dev Active 6s
kube-flannel Active 31h
kube-node-lease Active 31h
kube-public Active 31h
kube-system Active 31h
[root@k8s-master ~]#
- 删除
# 删除namespace
[root@k8s-master ~]# kubectl delete ns dev
namespace "dev" deleted
[root@k8s-master ~]# kubectl get ns
NAME STATUS AGE
default Active 31h
kube-flannel Active 31h
kube-node-lease Active 31h
kube-public Active 31h
kube-system Active 31h
[root@k8s-master ~]#
- 配置方式
首先准备一个yaml文件：ns-dev.yaml
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
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。
- 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：
[root@k8s-master ~]# kubectl get pods -n kube-system
NAME READY STATUS RESTARTS AGE
coredns-c676cc86f-44bsf 1/1 Running 5 (143m ago) 32h
coredns-c676cc86f-fbb7f 1/1 Running 5 (143m ago) 32h
etcd-k8s-master 1/1 Running 5 (143m ago) 32h
kube-apiserver-k8s-master 1/1 Running 5 (143m ago) 32h
kube-controller-manager-k8s-master 1/1 Running 7 (143m ago) 32h
kube-proxy-65lcn 1/1 Running 5 (143m ago) 32h
kube-proxy-lw4z2 1/1 Running 5 (143m ago) 26h
kube-proxy-zskvf 1/1 Running 6 (143m ago) 26h
kube-scheduler-k8s-master 1/1 Running 8 (143m ago) 32h
[root@k8s-master ~]#
2.1 管理pod
-
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
# 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@master ~]# kubectl run nginx --image=nginx:latest --port=80 --namespace dev
deployment.apps/nginx created
[root@k8s-master ~]# kubectl create ns dev
namespace/dev created
[root@k8s-master ~]# kubectl run nginx --image nginx --port 80 -n dev
pod/nginx created
- 查看pod信息
# 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 7m25s
# 查看Pod的详细信息
[root@k8s-master ~]# kubectl describe pod nginx -n dev
Name: nginx
Namespace: dev
Priority: 0
Service Account: default
Node: k8s-node2/192.168.232.134
Start Time: Wed, 07 Sep 2022 21:47:22 +0800
Labels: run=nginx
Annotations: <none>
Status: Running
IP: 10.244.2.14
IPs:
IP: 10.244.2.14
Containers:
nginx:
Container ID: containerd://c1a9c5d6c53c2888215fa88d513f926eeed1ab7bb2a0f769aee40a23a3e0a07e
Image: nginx
Image ID: docker.io/library/nginx@sha256:b95a99feebf7797479e0c5eb5ec0bdfa5d9f504bc94da550c2f58e839ea6914f
Port: 80/TCP
Host Port: 0/TCP
State: Running
Started: Wed, 07 Sep 2022 21:47:27 +0800
Ready: True
Restart Count: 0
Environment: <none>
Mounts:
/var/run/secrets/kubernetes.io/serviceaccount from kube-api-access-sl4m5 (ro)
Conditions:
Type Status
Initialized True
Ready True
ContainersReady True
PodScheduled True
Volumes:
kube-api-access-sl4m5:
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 8m11s default-scheduler Successfully assigned dev/nginx to k8s-node2
Normal Pulling 8m9s kubelet Pulling image "nginx"
Normal Pulled 8m5s kubelet Successfully pulled image "nginx" in 4.409994145s
Normal Created 8m5s kubelet Created container nginx
Normal Started 8m5s kubelet Started container nginx
[root@k8s-master ~]#
[root@k8s-master ~]# kubectl get svc
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
apache NodePort 10.100.81.244 <none> 80:31552/TCP 23h
kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 32h
nginx NodePort 10.105.183.188 <none> 80:30735/TCP 26h
[root@k8s-master ~]#
10.105.183.188:集群ip
- 访问Pod
# 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 15m 10.244.2.14 k8s-node2 <none> <none>
[root@k8s-master ~]#
#访问POD
[root@k8s-master ~]# curl 10.244.2.14
<!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 ~]#
- 先多创建几个
[root@k8s-master ~]# kubectl run nginx1 --image nginx --port 80 -n dev
pod/nginx1 created
[root@k8s-master ~]# kubectl run nginx2 --image nginx --port 80 -n dev
pod/nginx2 created
[root@k8s-master ~]# kubectl run nginx3 --image nginx --port 80 -n dev
pod/nginx3 created
[root@k8s-master ~]#
[root@k8s-master ~]# kubectl get pods -n dev
NAME READY STATUS RESTARTS AGE
nginx 1/1 Running 0 22m
nginx1 1/1 Running 0 50s
nginx2 1/1 Running 0 46s
nginx3 1/1 Running 0 41s
[root@k8s-master ~]#
- 删除指定Pod
# 删除指定Pod
[root@k8s-master ~]# kubectl get pods -n dev
NAME READY STATUS RESTARTS AGE
nginx 1/1 Running 0 22m
nginx1 1/1 Running 0 50s
nginx2 1/1 Running 0 46s
nginx3 1/1 Running 0 41s
[root@k8s-master ~]# kubectl delete pod nginx -n dev
pod "nginx" deleted
# 先来查询一下当前namespace下的Pod控制器
[root@k8s-master ~]# kubectl get pods -n dev
NAME READY STATUS RESTARTS AGE
nginx1 1/1 Running 0 12m
nginx2 1/1 Running 0 12m
nginx3 1/1 Running 0 12m
# 接下来，删除此Pod控制器
-
配置操作
-
创建一个pod.yml，内容如下：
[root@k8s-master manifest]# vim pod.yml
[root@k8s-master manifest]# cat pod.yml
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 manifest]#
[root@k8s-master manifest]# kubectl apply -f pod.yml
namespace/dev created
pod/nginx created
[root@k8s-master manifest]# kubectl get pods -n dev
NAME READY STATUS RESTARTS AGE
nginx 1/1 Running 0 12s
[root@k8s-master manifest]#
[root@k8s-master manifest]# kubectl get -f pod.yml
NAME STATUS AGE
namespace/dev Active 33s
NAME READY STATUS RESTARTS AGE
pod/nginx 1/1 Running 0 33s
[root@k8s-master manifest]#
-
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. 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。
3.1 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
- 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
[root@k8s-master ~]# kubectl get svc
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
apache NodePort 10.100.81.244 <none> 80:31552/TCP 24h
kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 33h
[root@k8s-master ~]# kubectl describe svc apache
Name: apache
Namespace: default
Labels: app=apache
Annotations: <none>
Selector: app=apache
Type: NodePort
IP Family Policy: SingleStack
IP Families: IPv4
IP: 10.100.81.244
IPs: 10.100.81.244
Port: <unset> 80/TCP
TargetPort: 80/TCP
NodePort: <unset> 31552/TCP
Endpoints: 10.244.1.7:80
Session Affinity: None
External Traffic Policy: Cluster
Events: <none>
[root@k8s-master ~]#
标签：
Labels: app=apache key；app 值:等于多少
- 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"......stable稳定版
环境标签："environment":"dev"，"environment":"test"，"environment":"prod" dev开发环境，test，测试，prod，生产环境
架构标签："tier":"frontend/前端"，"tier":"backend/后端"
3.2 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
3.3 有两种Label Selector（选择器）：
1. 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
2. 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（多个对象）
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
3.4 标签选择器
-
当大量的pod运行在一个集群当中时，如何实现分类管理?比如想删除某一类pod，比如想让控制器去管理一部分pod，它怎么进行管理?如何挑选、检测出来这些pod呢?值得肯定的是,这么多的pod，我们不能通过pod的名称来识别容器，因为pod随时都会被创建和删除,当一个pod发生故障被删除后，重新生成的pod的名称与被删除的pod名称肯定是不一样的,只不过其内部运行的程序是—样的,所以我们不能靠pod的名称来识别。
-
同时我们有可能要将一类pod归组，比如创建4个nginx的pod,期望使用一个控制器对其进行统一管理，删除一个控制器就把这4个pod都删了，控制器还要保证这4个pod都处于运行状态，缺一个要补一个，多一个要多杀一个，精确符合我们期望的4个pod才行。
-
为了能够实现pod识别需要在pod之上附加一些元数据，类似dockerfle中的label标签的方式，比如在创建pod时为其附加一个名为app的key，然后将其值设为nginx，那么当我们在批量进行pod调度管理时，可以检查pod中是否有app这个key，且其值是否为nginx，通过此种方法来识别pod是否是我们想要控制的pod
-
标签是在k8s上管理大规模pod资源并且能够分类识别和管理的一个非常重要的途径，是一个识别资源重要的参数
-
通过标签选择器组件我们可以实现这个功能从众多的pod中筛选出我们想要的pod
-
标签选择器就是一种根据标签来过滤符合条件的资源对象的机制
3.5 使用命令方式打标签
先查看标签：
[root@k8s-master ~]# kubectl get pods -n devNAME READY STATUS RESTARTS AGE
nginx 1/1 Running 0 66m
[root@k8s-master ~]# kubectl describe pod nginx -n dev|grep -i label
Labels: <none>
[root@k8s-master ~]#
[root@k8s-master ~]# kubectl get pods -n devNAME READY STATUS RESTARTS AGE
mynginx 1/1 Running 0 2m29s
nginx 1/1 Running 0 72m
nginx1 1/1 Running 0 2m48s
nginxpod 1/1 Running 0 4m4s
[root@k8s-master ~]#
# 为pod资源打标签
[root@k8s-master ~]# kubectl label pod nginx -n dev app=nginx
pod/nginx labeled
[root@k8s-master ~]#
[root@k8s-master ~]# kubectl label pod nginx1 -n dev app=nginx1
pod/nginx1 labeled
[root@k8s-master ~]# kubectl label pod nginxpod -n dev app=nginxpod
pod/nginxpod labeled
[root@k8s-master ~]# kubectl label pod mynginx -n dev app=mynginx
pod/mynginx labeled
[root@k8s-master ~]#
# 为pod资源更新标签
[root@k8s-master ~]# kubectl label pod nginx -n dev app=test
error: 'app' already has a value (nginx), and --overwrite is false
[root@k8s-master ~]# kubectl label pod nginx -n dev app=test --overwrite
pod/nginx labeled
[root@k8s-master ~]#
[root@k8s-master ~]# kubectl get pod nginx -n dev --show-labels
NAME READY STATUS RESTARTS AGE LABELS
nginx 1/1 Running 0 74m app=nginx
[root@k8s-master ~]# kubectl get pod nginx -n dev --show-labels
NAME READY STATUS RESTARTS AGE LABELS
nginx 1/1 Running 0 74m app=test
[root@k8s-master ~]#
# 查看标签
[root@k8s-master ~]# kubectl describe pod nginx -n dev|grep -i label
Labels: app=nginx
[root@k8s-master ~]# kubectl get pod nginx -n dev --show-labels
NAME READY STATUS RESTARTS AGE LABELS
nginx 1/1 Running 0 71m app=nginx
[root@k8s-master ~]#
查看所有标签
[root@k8s-master ~]# kubectl get pods -n dev --show-labels
NAME READY STATUS RESTARTS AGE LABELS
mynginx 1/1 Running 0 7m10s app=mynginx
nginx 1/1 Running 0 76m app=test
nginx1 1/1 Running 0 7m29s app=nginx1
nginxpod 1/1 Running 0 8m45s app=nginxpod
[root@k8s-master ~]#
# 筛选标签：kubectl get pods -n dev -l app=test --show-labels
[root@k8s-master ~]# kubectl get pods -n dev --show-labels
NAME READY STATUS RESTARTS AGE LABELS
mynginx 1/1 Running 0 7m48s app=mynginx
nginx 1/1 Running 0 77m app=test
nginx1 1/1 Running 0 8m7s app=nginx1
nginxpod 1/1 Running 0 9m23s app=nginxpod
筛选某一个标签
[root@k8s-master ~]# kubectl get pods -n dev -l app=test --show-labels
NAME READY STATUS RESTARTS AGE LABELS
nginx 1/1 Running 0 78m app=test
[root@k8s-master ~]#
除了被筛选的
[root@k8s-master ~]# kubectl get pods -n dev -l app!=test --show-labels
NAME READY STATUS RESTARTS AGE LABELS
mynginx 1/1 Running 0 10m app=mynginx
nginx1 1/1 Running 0 10m app=nginx1
nginxpod 1/1 Running 0 11m app=nginxpod
[root@k8s-master ~]#
#删除标签
[root@k8s-master ~]# kubectl label pod nginx1 -n dev app-
pod/nginx1 unlabeled
[root@k8s-master ~]# kubectl get pods -n dev --show-labels
NAME READY STATUS RESTARTS AGE LABELS
mynginx 1/1 Running 0 12m app=mynginx
nginx 1/1 Running 0 81m app=test
nginx1 1/1 Running 0 12m <none>
nginxpod 1/1 Running 0 13m app=nginxpod
[root@k8s-master ~]#
3.6 使用配置文件方式打标签
方法：
使用kubectl explain pod查看pod
kubectl explain pod.metadata
[root@k8s-master manifest]# cat nginx.yml
apiVersion: v1
kind: Pod
metadata:
labels:
app: web
env: test
name: httpd
namespace: default
spec:
containers:
- image: httpd:latest
imagePullPolicy: IfNotPresent
name: apache
ports:
- containerPort: 80
hostPort: 8080
protocol: TCP
[root@k8s-master manifest]#
[root@k8s-master manifest]# kubectl apply -f nginx.yml
pod/httpd created
[root@k8s-master manifest]# kubectl get -f nginx.yml
NAME READY STATUS RESTARTS AGE
httpd 1/1 Running 0 9s
[root@k8s-master manifest]# kubectl get pods
NAME READY STATUS RESTARTS AGE
httpd 1/1 Running 0 45s
[root@k8s-master manifest]# kubectl get pods -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
httpd 1/1 Running 0 59s 10.244.2.29 k8s-node2 <none> <none>
[root@k8s-master manifest]# kubectl get pods,svc
NAME READY STATUS RESTARTS AGE
pod/httpd 1/1 Running 0 77s
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
service/apache NodePort 10.100.81.244 <none> 80:31552/TCP 45h
service/kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 2d6h
[root@k8s-master manifest]#
标签：
[root@k8s-master ~]# kubectl get pods --show-labels
NAME READY STATUS RESTARTS AGE LABELS
httpd 1/1 Running 0 3m3s app=web,env=test
[root@k8s-master ~]#
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。[外链图片转存失败,源站可能有防盗链机制,建议将图片保存下来直接上传(img-ujhsGytJ-1662650502116)(16622971823227.jpg)]
-
pod挂掉之后，会重启一个，pod中有标签，然后受deployment管理
4.1 命令操作
# 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 manifest]# kubectl create deploy nginx --image nginx --port 80 --replicas 3
deployment.apps/nginx created
# 查看创建的Pod
[root@k8s-master manifest]# kubectl get pods
NAME READY STATUS RESTARTS AGE
httpd 1/1 Running 0 12m
nginx-ff6774dc6-88hvn 1/1 Running 0 2m4s
nginx-ff6774dc6-p9gf6 1/1 Running 0 2m4s
nginx-ff6774dc6-pkn6h 1/1 Running 0 2m4s
[root@k8s-master manifest]#
[root@k8s-master manifest]# kubectl get pods -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
httpd 1/1 Running 0 12m 10.244.2.29 k8s-node2 <none> <none>
nginx-ff6774dc6-88hvn 1/1 Running 0 2m22s 10.244.2.30 k8s-node2 <none> <none>
nginx-ff6774dc6-p9gf6 1/1 Running 0 2m22s 10.244.1.19 k8s-node1 <none> <none>
nginx-ff6774dc6-pkn6h 1/1 Running 0 2m22s 10.244.1.18 k8s-node1 <none> <none>
[root@k8s-master manifest]#
# 查看deployment的信息
[root@k8s-master manifest]# kubectl get deploy
NAME READY UP-TO-DATE AVAILABLE AGE
nginx 3/3 3 3 5m10s
[root@k8s-master manifest]#
# UP-TO-DATE：成功升级的副本数量
# AVAILABLE：可用副本的数量
#删除或者挂掉一个会自动重启一个
[root@k8s-master manifest]# kubectl delete pods nginx-ff6774dc6-88hvn
pod "nginx-ff6774dc6-88hvn" deleted
[root@k8s-master manifest]# kubectl get pods
NAME READY STATUS RESTARTS AGE
httpd 1/1 Running 0 13m
nginx-ff6774dc6-glcmr 0/1 ContainerCreating 0 3s
nginx-ff6774dc6-p9gf6 1/1 Running 0 3m29s
nginx-ff6774dc6-pkn6h 1/1 Running 0 3m29s
[root@k8s-master manifest]#
# 删除
[root@k8s-master manifest]# kubectl delete deploy nginx
deployment.apps "nginx" deleted
[root@k8s-master manifest]# kubectl get deploy
No resources found in default namespace.
# 查看deployment的详细信息 describe
[root@k8s-master manifest]# kubectl describe deploy nginx
Name: nginx#控制器名称
Namespace: default#默认的名称空间
CreationTimestamp: Thu, 08 Sep 2022 19:46:08 +0800#时间戳
Labels: #标签 app=nginx
Annotations: deployment.kubernetes.io/revision: 1
Selector: #标签选择器 app=nginx
Replicas: 3 desired | 3 updated | 3 total | 3 available | 0 unavailable#定义的副本数
StrategyType:#类型 RollingUpdate#滚动更新
MinReadySeconds: 0
RollingUpdateStrategy: 25% max unavailable, 25% max surge#25% max假如有4个容器，容忍有一个挂了，用一个新镜像启动一个新的，干掉一个旧的，启动一个新的
Pod Template:#pod模板
Labels: app=nginx
Containers:
nginx:
Image: nginx
Port: 80/TCP
Host Port: 0/TCP
Environment: <none>
Mounts: <none>
Volumes: <none>
Conditions:
Type Status Reason
---- ------ ------
Progressing True NewReplicaSetAvailable
Available True MinimumReplicasAvailable
OldReplicaSets: <none>
NewReplicaSet: nginx-ff6774dc6 (3/3 replicas created)
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal ScalingReplicaSet 5m56s deployment-controller Scaled up replica set nginx-ff6774dc6 to 3
[root@k8s-master manifest]#
4.2 配置操作
[root@k8s-master ~]# kubectl explain deploy
replicas：启动多少个pod
[root@k8s-master manifest]# vim deploy.yml
[root@k8s-master manifest]# cat deploy.yml
apiVersion: apps/v1
kind: Deployment
metadata:
labels:#这个标签给appche1使用
app: web1
namespace: default
name: appche1
spec:
replicas: 3 ###启动3个pod
selector:
matchLabels:###匹配标签
app: httpd
template:
metadata:
labels: ###定义标签
app: httpd
name: apache2
namespace: default
spec:
containers:
- name: httpdv1
image: httpd:latest
imagePullPolicy: IfNotPresent#有镜像的时候不拉取
[root@k8s-master manifest]#
kubectl apply/create -f deploy.yml
[root@k8s-master manifest]# kubectl apply -f deploy.yml
deployment.apps/appche1 created
[root@k8s-master manifest]# kubectl get deploy
NAME READY UP-TO-DATE AVAILABLE AGE
appche1 3/3 3 3 14s
[root@k8s-master manifest]# kubectl get pods
NAME READY STATUS RESTARTS AGE
appche1-7978b74cd-jhqft 1/1 Running 0 19s
appche1-7978b74cd-kq2vf 1/1 Running 0 19s
appche1-7978b74cd-wqwjc 1/1 Running 0 19s
[root@k8s-master manifest]#
[root@k8s-master manifest]# kubectl get pods --show-labels
NAME READY STATUS RESTARTS AGE LABELS
appche1-7978b74cd-jhqft 1/1 Running 0 64s app=httpd,pod-template-hash=7978b74cd
appche1-7978b74cd-kq2vf 1/1 Running 0 64s app=httpd,pod-template-hash=7978b74cd
appche1-7978b74cd-wqwjc 1/1 Running 0 64s app=httpd,pod-template-hash=7978b74cd
[root@k8s-master manifest]#
删除一个又重启一个
[root@k8s-master manifest]# kubectl delete pod appche1-7978b74cd-kq2vf
pod "appche1-7978b74cd-kq2vf" deleted
[root@k8s-master manifest]# kubectl get pods --show-labelsNAME READY STATUS RESTARTS AGE LABELS
appche1-7978b74cd-7rjm6 1/1 Running 0 4s app=httpd,pod-template-hash=7978b74cd
appche1-7978b74cd-jhqft 1/1 Running 0 2m28s app=httpd,pod-template-hash=7978b74cd
appche1-7978b74cd-wqwjc 1/1 Running 0 2m28s app=httpd,pod-template-hash=7978b74cd
[root@k8s-master manifest]#
- 这样创建之后不能访问：需要创建service
5. Service
5.1 每个Pod都会分配一个单独的Pod IP，会存在如下两问题：
- 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
5.2 kubernetes设计了Service
-
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。
-
通过标签选择器的方式来访问
5.3 创建集群内部可访问的Service
[root@k8s-master ~]# kubectl get deploy
NAME READY UP-TO-DATE AVAILABLE AGE
appche1 3/3 3 3 59m
# 暴露Service
[root@k8s-master ~]# kubectl expose deploy appche1 --name web --type ClusterIP --port 80 --target-port 80
service/web exposed
# 查看service
[root@k8s-master ~]# kubectl get svc -o wide
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE SELECTOR
kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 2d8h <none>
web ClusterIP 10.97.123.191 <none> 80/TCP 88s app=httpd
[root@k8s-master ~]#
[root@k8s-master ~]# kubectl get svc
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 2d8h
web ClusterIP 10.97.123.191 <none> 80/TCP 58s
# 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 10.97.123.191
<html><body><h1>It works!</h1></body></html>
只能在集群访问
5.4 创建集群外部也可访问的Service
# 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 deploy appche1 --name web1 --type NodePort --port 80 --target-port 80
service/web1 exposed
# 此时查看，会发现出现了NodePort类型的Service，而且有一对Port（80:30318/TC）
[root@k8s-master ~]# kubectl get svc -o wideNAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE SELECTOR
kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 2d8h <none>
web ClusterIP 10.97.123.191 <none> 80/TCP 4m48s app=httpd
web1 NodePort 10.96.117.74 <none> 80:30318/TCP 4s app=httpd
[root@k8s-master ~]#
30318在防火墙规则iptables中
[root@k8s-master ~]# iptables -t nat -nvL|grep 30318
2 104 KUBE-EXT-7P2N65YGDDETDSYJ tcp -- * * 0.0.0.0/0 0.0.0.0/0 /* default/web1 */ tcp dpt:30318
[root@k8s-master ~]#
# 接下来就可以通过集群外的主机访问 节点IP:30318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
node1和node2都能访问
删除Service
[root@k8s-master ~]# kubectl get svc
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 2d8h
web ClusterIP 10.97.123.191 <none> 80/TCP 12m
web1 NodePort 10.96.117.74 <none> 80:30318/TCP 7m57s
[root@k8s-master ~]# kubectl delete svc web
service "web" deleted
[root@k8s-master ~]# kubectl delete svc web1
service "web1" deleted
[root@k8s-master ~]#
- 访问：http://192.168.232.128:30318/
![[外链图片转存失败,源站可能有防盗链机制,建议将图片保存下来直接上传(img-kJKw1TOB-1662650502118)(image-20220908222232976.png)]](/image/aHR0cHM6Ly9pLWJsb2cuY3NkbmltZy5jbi9ibG9nX21pZ3JhdGUvNzliYmFjZmM4ZDFhMmRkMjdiMDMyOGViNzVjYTgyZjQucG5n)
5.5 配置方式
[root@k8s-master manifest]# vim svc.yml
[root@k8s-master manifest]# cat svc.yml
apiVersion: v1
kind: Service
metadata:
name: web
spec:
ports:
- port: 80
protocol: TCP
targetPort: 80
selector:
app: httpd
type: NodePort
[root@k8s-master manifest]#
[root@k8s-master manifest]# kubectl apply -f svc.yml
service/nginx created
[root@k8s-master manifest]# kubectl get -f svc.yml
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
nginx NodePort 10.109.154.107 <none> 80:30797/TCP 19s
[root@k8s-master manifest]# kubectl get pods
NAME READY STATUS RESTARTS AGE
appche1-7978b74cd-7rjm6 1/1 Running 0 110m
appche1-7978b74cd-jhqft 1/1 Running 0 112m
appche1-7978b74cd-wqwjc 1/1 Running 0 112m
[root@k8s-master manifest]# [root@k8s-master manifest]# kubectl get svc
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 2d9h
nginx NodePort 10.109.154.107 <none> 80:30797/TCP 100s
[root@k8s-master manifest]#
创建：kubectl create -f svc-nginx.yaml
删除：kubectl delete -f svc-nginx.yaml