关于kubernetes:扩展-Kubernetes-之-Kubectl-Plugin

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简介
kubectl 是重要的 kubernetes 治理 / 运维工具
kubectl 性能十分弱小, 常见的命令应用形式能够参考 kubectl –help，或者这篇文章
这篇文章首先会简略介绍几个 kubectl 你可能不晓得的小技巧，次要篇幅介绍 kubectl 的 plugin.
kubectl 小技巧

设置主动补全 kubectl completion zsh
查看资源 SPEC (有没有遇到过想看 SPEC 只能去查 API 文档或者翻代码的状况?) kubectl explain [–recursive]
给罕用的命令设置 alias, 比方笔者罕用的: kns=”kubectl -n kube-system”, kna=”kubectl –all-namespaces=true, kcc=”kubectl config use-context, kgy=”kubectl get -o yaml”, 或者间接应用这个我的项目生成的 alias, 这个我的项目应用一套规定生成了 800 多个 aliases

kubectl plguin
kubectl 反对一种简略的 plugin 机制，反对通过 kubectl 调用另一个二进制，实现 kubernetes 相干的一些性能（其实对二进制执行的性能没有任何限度）
目前这种机制并没有在 kubectl 和 plugin 传递任何信息，只对 plugin 有两点要求

plugin 为可执行文件
plugin 可执行文件的名字为 kubectl-$plugin_name

krew
本地装置形式很简略，只须要把可执行文件挪动到比方 /usr/local/bin，并且命名为 kubectl-$plugin_name 即可。然而做好到插件如何分享，以及如何获取他人装置到插件呢。kubectl 提供了一个 krew（他自身也是一个插件）工具提供了相应到性能
Available Commands:
help Help about any command
info Show information about a kubectl plugin
install Install kubectl plugins
list List installed kubectl plugins
search Discover kubectl plugins
uninstall Uninstall plugins
update Update the local copy of the plugin index
upgrade Upgrade installed plugins to newer versions
version Show krew version and diagnostics
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检索插件
能够应用命令 kubectl krew search, 然而这下面到介绍比拟简介，更好到形式是到这个 index 页面查看介绍和去对应的 github 仓库查看具体介绍。
➜ kubectl krew search
NAME DESCRIPTION INSTALLED
access-matrix Show an RBAC access matrix for server resources no
advise-psp Suggests PodSecurityPolicies for cluster. no
auth-proxy Authentication proxy to a pod or service no
bulk-action Do bulk actions on Kubernetes resources. no
ca-cert Print the PEM CA certificate of the current clu… no
capture Triggers a Sysdig capture to troubleshoot the r… no
…
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装置插件
应用 kubectl krew install
➜ kubectl krew install custom-cols
Updated the local copy of plugin index.
Installing plugin: custom-cols
Installed plugin: custom-cols
\
| Use this plugin:
| kubectl custom-cols
| Documentation:
| https://github.com/webofmars/…
| Caveats:
| \
| | The list of templates is for now limited and can be retrieved with the –help option.
| | Please feel free to submit any PR upstream (see github repo) to add more.
| /
/
WARNING: You installed a plugin from the krew-index plugin repository.
These plugins are not audited for security by the Krew maintainers.
Run them at your own risk.
(base)
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举荐插件介绍
change-ns
切换 ns, 用于切换 namespace，切换后会设置在 kubeconfig 中，后续的操作就不必再加 –namespaces 了。不过设置了 namespace 之后须要留神的是后续的命令默认 namespace 都是这个设置值了，如果你在 yaml 中没有写名 namespace，资源可能不会创立到你冀望的 default 目录上面了.
➜ kubectl change-ns kube-system
namespace changed to “kube-system”
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cssh
ssh 到 kubernetes node 下面去，会主动从 node 信息中提取外网 ip，并连贯 tmux 尝试做 ssh 登陆.

kubectl cssh –help
Allows users to SSH into Kubernetes nodes by opening a new tmux pane for each matching node

Options:
-a, –address-type=’ExternalIP’: Node address type to query for (e.g. InternalIP/ExternalIP)
-i, –identity-file=”: Selects a file from which the identity (private key) for public key authentication is read
-l, –selector=”: Selector (label query) to filter on, supports ‘=’, ‘==’, and ‘!=’.(e.g. -l key1=value1,key2=value2)
-p, –port=”: SSH port
-u, –username=”: SSH Username

kubectl cssh –username=ubuntu
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debug/spy
两个插件的作用差不多，目标都是进去 container 的命名空间进行 debug，不同到是 debug 依赖一个 EphemeralContainers feature, 而 spy 不依赖
➜ kubectl spy kube-dns-d5876cbfd-r8kh4
loading spy pod…
If you don’t see a command prompt, try pressing enter.
/ # ps
PID USER TIME COMMAND

1 root     12:56 /dnsmasq-nanny -v=2 -logtostderr -configDir=/etc/k8s/dns/dnsmasq-nanny -restartDnsmasq=true -- -k --cache-size=1000 --log-facility=- --server=/cluster.local/12

16 root 14:55 /usr/sbin/dnsmasq -k –cache-size=1000 –log-facility=- –server=/cluster.local/127.0.0.1#10053 –server=/in-addr.arpa/127.0.0.1#10053 –server=/ip6.arpa/127.0
21 root 0:00 sh
28 root 0:00 ps
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还有一个罕用的 debug 命令也能够设做 alias
kubectl run –rm -i -t test –image=byrnedo/alpine-curl –restart=Never –limits=cpu=10m,memory=10Mi –command=true /bin/sh
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tree
用 tree 的模式展现 Kubernetes objects
➜ kubectl tree deployment kube-dns
NAMESPACE NAME READY REASON AGE
kube-system Deployment/kube-dns – 286d
kube-system ├─ReplicaSet/kube-dns-898dbbfc6 – 286d
kube-system └─ReplicaSet/kube-dns-d5876cbfd – 141d
kube-system ├─Pod/kube-dns-d5876cbfd-r8kh4 True 141d
kube-system └─Pod/kube-dns-d5876cbfd-w8xvh True 141d
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trace/sniff
别离用 bpftrace/tcpdump 工具对 pod 进行 debug
kubectl trace run ip-180-12-0-152.ec2.internal -f read.bt
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➜ kubectl sniff prometheus-k8s-0 -n monitoring
INFO[0000] sniffing method: upload static tcpdump
INFO[0000] using tcpdump path at: ‘/Users/leiwang/.krew/store/sniff/v1.3.1/static-tcpdump’
INFO[0000] no container specified, taking first container we found in pod.
INFO[0000] selected container: ‘prometheus’
INFO[0000] sniffing on pod: ‘prometheus-k8s-0’ [namespace: ‘monitoring’, container: ‘prometheus’, filter: ”, interface: ‘any’]
INFO[0000] uploading static tcpdump binary from: ‘/Users/leiwang/.krew/store/sniff/v1.3.1/static-tcpdump’ to: ‘/tmp/static-tcpdump’
INFO[0000] uploading file: ‘/Users/leiwang/.krew/store/sniff/v1.3.1/static-tcpdump’ to ‘/tmp/static-tcpdump’ on container: ‘prometheus’
INFO[0000] executing command: ‘[/bin/sh -c ls -alt /tmp/static-tcpdump]’ on container: ‘prometheus’, pod: ‘prometheus-k8s-0’, namespace: ‘monitoring’
INFO[0000] command: ‘[/bin/sh -c ls -alt /tmp/static-tcpdump]’ executing successfully exitCode: ‘0’, stdErr :”
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dig
获取对于 kubernetes node 的所有信息

go get -u github.com/sysdiglabs/kubectl-dig/cmd/kubectl-dig
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warp
是 kubectl run + sshd-rsync 命令的合成，能够不便在在 pod 中执行一个本地文件.

cd examples/nodejs
kubectl warp -i -t –image node testing-node — npm run watch
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get-all
get all, 慎用，和 kubectl 的 get –all 不同，这个命令是真的 all
➜ kubectl get-all
NAME NAMESPACE AGE
componentstatus/scheduler <unknown>
componentstatus/controller-manager <unknown>
componentstatus/etcd-0 <unknown>
configmap/token-100001343833 100001343833 69d
configmap/token-100002873007 100002873007 77d
…
…
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grep
grep by name
➜ kubectl grep pods -A nginx
NAMESPACE NAME READY STATUS RESTART AGE
default nginx-6dc5bfc797-vwdz7 1/1 Running 0 31d
monitoring prometheus-nginx-656ddc9c86-nq9dk 1/1 Running 1 181d
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konfig
当你频繁创立 kubernetes 集群须要 import 配置的时候很有用
kubectl konfig import –save ~/Downloads/cls-5en24mcc-config
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doctor
诊断 kubernetes 集群，目前做了一下的一些查看

core component health (etcd cluster members, scheduler, controller-manager)
orphan endpoints (endpoints with no ipv4 attached)
persistent-volume available & unclaimed
persistent-volume-claim in lost state
k8s nodes that are not in ready state
orphan replicasets (desired number of replicas are bigger than 0 but the available replicas are 0)
leftover replicasets (desired number of replicas and the available # of replicas are 0)
orphan deployments (desired number of replicas are bigger than 0 but the available replicas are 0)
leftover deployments (desired number of replicas and the available # of replicas are 0)
leftover cronjobs (last active date is more than 30 days)

open-svc
利用 kubectl proxy 开启近程转发，不便 debug
➜ kubectl open-svc prometheus-k8s -n monitoring
Starting to serve on 127.0.0.1:8001
Opening service/prometheus-k8s in the default browser…
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resource-capacity/view-utilization
察看 node/pod/namespace 等的资源申请和应用状况
➜ kubectl resource-capacity –pods
NODE NAMESPACE POD CPU REQUESTS CPU LIMITS MEMORY REQUESTS MEMORY LIMITS

- - 39728m (45%) 52108m (59%) 85069Mi (43%) 111368Mi (56%)

10.0.0.10 762m (19%) 1252m (31%) 585Mi (8%) 2399Mi (34%)
10.0.0.10 kube-system ccs-log-collector-r4w6m 300m (7%) 1000m (25%) 238Mi (3%) 1907Mi (27%)
10.0.0.10 kube-system etcd-10.0.0.10 0m (0%) 0m (0%) 0Mi (0%) 0Mi (0%)
10.0.0.10 kube-system gpu-quota-admission-10.0.0.10 0m (0%) 0m (0%) 0Mi (0%) 0Mi (0%)
10.0.0.10 kube-system kube-apiserver-10.0.0.10 0m (0%) 0m (0%) 0Mi (0%) 0Mi (0%)
10.0.0.10 kube-system kube-controller-manager-10.0.0.10 0m (0%) 0m (0%) 0Mi (0%) 0Mi (0%)
10.0.0.10 kube-system kube-dns-d5876cbfd-w8xvh 260m (6%) 0m (0%) 66Mi (0%) 162Mi (2%)
10.0.0.10 kube-system kube-proxy-8m2cf 0m (0%) 0m (0%) 0Mi (0%) 0Mi (0%)
10.0.0.10 kube-system kube-router-n86t5 100m (2%) 150m (3%) 100Mi (1%) 150Mi (2%)
10.0.0.10 monitoring node-exporter-hdspv 102m (2%) 102m (2%) 180Mi (2%) 180Mi (2%)
10.0.0.10 kube-system tke-bridge-agent-dlmhs 0m (0%) 0m (0%) 0Mi (0%) 0Mi (0%)
10.0.0.10 kube-system tke-cni-agent-cdfhs 0m (0%) 0m (0%) 0Mi (0%) 0Mi (0%)

10.0.0.13 7632m (48%) 9782m (61%) 24290Mi (80%) 28981Mi (96%)
10.0.0.13 100010987341 a2sc75rcc7x8x664-64ff96c4d5-wsks6 2000m (12%) 2000m (12%) 2048Mi (6%) 2048Mi (6%)
10.0.0.13 100010987341 a2sc75rcc7x8x664-8459df9d4d-dc48m 2000m (12%) 2000m (12%) 10240Mi (34%) 10240Mi (34%)
10.0.0.13 100010987341 a2sc75rcc7x8x664-8459df9d4d-kktgx 2000m (12%) 2000m (12%) 10240Mi (34%) 10240Mi (34%)
10.0.0.13 kube-system ccs-log-collector-flmcq 300m (1%) 1000m (6%) 238Mi (0%) 1907Mi (6%)
10.0.0.13 kube-system ip-masq-agent-lnq4c 0m (0%) 0m (0%) 0Mi (0%) 0Mi (0%)
10.0.0.13 kube-system kube-proxy-sjn7j 0m (0%) 0m (0%) 0Mi (0%) 0Mi (0%)
10.0.0.13 kube-system kube-router-d8dgw 100m (0%) 150m (0%) 100Mi (0%) 150Mi (0%)
10.0.0.13 monitoring node-exporter-jths9 102m (0%) 102m (0%) 180Mi (0%) 180Mi (0%)
10.0.0.13 monitoring prometheus-k8s-test-3-0 65m (0%) 15m (0%) 110Mi (0%) 60Mi (0%)
10.0.0.13 monitoring prometheus-k8s-test-5-0 65m (0%) 15m (0%) 110Mi (0%) 60Mi (0%)
10.0.0.13 kube-system service-controller-6fcb5fc4f4-cvmfz 250m (1%) 1000m (6%) 256Mi (0%) 1024Mi (3%)
10.0.0.13 541004974 test-75c58cd5f7-qgm7m 750m (4%) 1500m (9%) 768Mi (2%) 3072Mi (10%)
10.0.0.13 kube-system tke-bridge-agent-9n2k9 0m (0%) 0m (0%) 0Mi (0%) 0Mi (0%)
10.0.0.13 kube-system tke-cni-agent-pmwpf 0m (0%) 0m (0%) 0Mi (0%) 0Mi (0%)
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➜ kubectl view-utilization node -h
CPU : ▄▆▄▇▃▃▆▃▅▂▆▃
Memory: ▇▅▂▆▁▃▃▄▇▂▇▃

         CPU                   Memory

Node Req %R Lim %L Req %R Lim %L
10.0.0.10 0.76 19% 1.3 31% 600M 8% 2.5G 36%
10.0.0.13 6.9 43% 8.3 52% 23G 78% 25G 86%
10.0.0.17 1 25% 3.3 82% 1G 15% 4.3G 63%
10.0.0.31 1.5 38% 2.3 57% 2.5G 13% 4.3G 23%
10.0.0.4 11 75% 13 86% 23G 74% 25G 83%
10.0.0.44 0.57 14% 1.3 32% 640M 3% 2.4G 13%

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