15 个 Kubectl 现有命令使用技巧 - 拿来即用

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发布于 2020-11-02 11:13:50

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发布于 2020-11-02 11:13:50

集群节点与pods

获取集群中所有non-running的pods(k是kubectl的命令别名)

☸️  CloudnativeEcosystem? default  ~  ? ? k get pods -A --field-selector=status.phase!=Running | \
    grep -v Complete

获取集群中所有节点以及他们的内存大小

☸️  CloudnativeEcosystem? default  ~  ? ? k get no -o json | \
  jq -r '.items | sort_by(.status.capacity.memory)[]|[.metadata.name,.status.capacity.memory]| @tsv'

master.devopsman.cn     2029760Ki
node1.devopsman.cn      2029760Ki
node2.devopsman.cn      2029760Ki

查看每个node节点上运行多少pods

☸️  CloudnativeEcosystem? default  ~  ? ? k get po -o json --all-namespaces | \
  jq '.items | group_by(.spec.nodeName) | map({"nodeName": .[0].spec.nodeName, "count": length}) | sort_by(.count)'
[
  {
    "nodeName": "node1.devopsman.cn",
    "count": 4
  },
  {
    "nodeName": "master.devopsman.cn",
    "count": 8
  },
  {
    "nodeName": "node2.devopsman.cn",
    "count": 11
  }
]

pods资源限制limits与requests

使用Kubectl top获取消耗CPU和内存资源的Pod列表的方法，可以按需排序

☸️  CloudnativeEcosystem? default  ~  ? ? k top pods -A | sort --reverse --key 3 --numeric
...
kube-system      coredns-66bff467f8-7hktk                            2m           18Mi            
default          traefik-577bb96ffb-tx2p2                            2m           32Mi            
kube-system      metrics-server-58f6f5594b-rsh8h                     1m           13Mi            
kube-system      kube-sealyun-lvscare-node2.devopsman.cn             1m           10Mi            
kube-system      kube-proxy-msrxn                                    1m           27Mi            
kube-system      kube-proxy-fts6g                                    1m           23Mi            
kube-system      calico-kube-controllers-84445dd79f-zbtk4            1m           14Mi            
default          nginx-744f4df6df-8wmmj                              0m           6Mi             
NAMESPACE        NAME                                                CPU(cores)   MEMORY(bytes)

按照podsrestart的次数进行排序,当然还可以使用其他状态进行排序

☸️  CloudnativeEcosystem? default  ~  ? ? bash -c "kubectl get pods --sort-by=.status.containerStatuses[0].restartCount"
NAME                                                READY   STATUS    RESTARTS   AGE
nginx-744f4df6df-8wmmj                              1/1     Running   1          14d
traefik-577bb96ffb-tx2p2                            1/1     Running   1          14d
dev-cluster-nfs-client-provisioner-755dcfbb-4fp86   1/1     Running   5          14d

6. 获取所有pods的limits和requests，并自定义列表头

☸️  CloudnativeEcosystem? default  ~  ? ? k get pods -A -o=custom-columns='NAME:spec.containers[*].name,MEMREQ:spec.containers[*].resources.requests.memory,MEMLIM:spec.containers[*].resources.limits.memory,CPUREQ:spec.containers[*].resources.requests.cpu,CPULIM:spec.containers[*].resources.limits.cpu'              
NAME                                 MEMREQ   MEMLIM   CPUREQ   CPULIM
...
dev-cluster-nfs-client-provisioner   <none>   <none>   <none>   <none>
nginx                                128Mi    128Mi    500m     500m
coredns                              70Mi     170Mi    100m     <none>
coredns                              70Mi     170Mi    100m     <none>
coredns                              70Mi     170Mi    100m     <none>
etcd                                 <none>   <none>   <none>   <none>

如果不知道当前版本的资源文件如何写，哪些explain会帮助你获取最正确的信息

☸️  CloudnativeEcosystem? default  ~  ? ? k explain sts                                                 KIND:     StatefulSet
VERSION:  apps/v1 # apiVersion

DESCRIPTION:
     StatefulSet represents a set of pods with consistent identities. Identities
     are defined as:
     - Network: A single stable DNS and hostname.
     - Storage: As many VolumeClaims as requested. The StatefulSet guarantees
     that a given network identity will always map to the same storage identity.

集群网络

想要获取集群节点internal IP的方法

☸️  CloudnativeEcosystem? default  ~  ? ? k get nodes -o json | \
  jq -r '.items[].status.addresses[]? | select (.type == "InternalIP") | .address' | \
  paste -sd "\n" -
192.168.99.128
192.168.99.133
192.168.99.134

获取集群中所有的svc以及各自的nodePort

☸️  CloudnativeEcosystem? default  ~  ? ? k get --all-namespaces svc -o json | \
  jq -r '.items[] | [.metadata.name,([.spec.ports[].nodePort | tostring ] | join("|"))]| @tsv'
kubernetes      null
nginx-svc       null
traefik null|null|null
traefikudp      30667
kube-dns        null|null|null
metrics-server  null
rmq-cluster     null
rmq-cluster-balancer    31489|32051

当flannel或者其他的容器网络插件CNI出现问题的时候，检查pod的路由信息是很重要的，下面列出pod的子网

☸️  CloudnativeEcosystem? default  ~  ? ? k get nodes -o jsonpath='{.items[*].spec.podCIDR}' | tr " " "\n"
100.64.0.0/24
100.64.2.0/24
100.64.1.0/24

集群日志

打印带有可读时间戳的日志

☸️  CloudnativeEcosystem? default  ~  ? ? k logs -f nginx-744f4df6df-8wmmj --timestamps                         
2020-10-05T08:43:32.3816926Z /docker-entrypoint.sh: /docker-entrypoint.d/ is not empty, will attempt to perform configuration
2020-10-05T08:43:32.381727847Z /docker-entrypoint.sh: Looking for shell scripts in /docker-entrypoint.d/
2020-10-05T08:43:32.387449329Z /docker-entrypoint.sh: Launching /docker-entrypoint.d/10-listen-on-ipv6-by-default.sh

查看最新的pod日志

☸️  CloudnativeEcosystem? default  ~  ? ? k logs -f nginx-744f4df6df-8wmmj --timestamps --tail=50
2020-10-05T08:43:32.3816926Z /docker-entrypoint.sh: /docker-entrypoint.d/ is not empty, will attempt to perform configuration
2020-10-05T08:43:32.381727847Z /docker-entrypoint.sh: Looking for shell scripts in /docker-entrypoint.d/
2020-10-05T08:43:32.387449329Z /docker-entrypoint.sh: Launching /docker-entrypoint.d/10-listen-on-ipv6-by-default.sh
2020-10-05T08:43:32.398286535Z 10-listen-on-ipv6-by-default.sh: Getting the checksum of /etc/nginx/conf.d/default.conf
2020-10-05T08:43:32.419095055Z 10-listen-on-ipv6-by-default.sh: Enabled listen on IPv6 in /etc/nginx/conf.d/default.conf
2020-10-05T08:43:32.419117067Z /docker-entrypoint.sh: Launching /docker-entrypoint.d/20-envsubst-on-templates.sh
2020-10-05T08:43:32.42342319Z /docker-entrypoint.sh: Configuration complete; ready for start up

打印pods内所有容器container的日志

☸️  CloudnativeEcosystem? default  ~  ? ? k logs -f nginx-744f4df6df-8wmmj --timestamps --tail=50 --all-containers

2020-10-05T08:43:32.3816926Z /docker-entrypoint.sh: /docker-entrypoint.d/ is not empty, will attempt to perform configuration
2020-10-05T08:43:32.381727847Z /docker-entrypoint.sh: Looking for shell scripts in /docker-entrypoint.d/
2020-10-05T08:43:32.387449329Z /docker-entrypoint.sh: Launching /docker-entrypoint.d/10-listen-on-ipv6-by-default.sh
2020-10-05T08:43:32.398286535Z 10-listen-on-ipv6-by-default.sh: Getting the checksum of /etc/nginx/conf.d/default.conf

获取previous容器的日志,比如已经crashed的

☸️  CloudnativeEcosystem? default  ~  ? ? k logs --help |grep 'previous'
  # Return snapshot of previous terminated ruby container logs from pod web-1
  -p, --previous=false: If true, print the logs for the previous instance of the container in a pod if it exists.

☸️  CloudnativeEcosystem? default  ~  ? ? k logs -f nginx-744f4df6df-8wmmj --timestamps --tail=50 --previous                
2020-10-05T05:16:40.322078192Z /docker-entrypoint.sh: Configuration complete; ready for start up
2020-10-05T05:17:31.117726669Z 100.110.232.4 - - [05/Oct/2020:05:17:31 +0000] "GET / HTTP/1.1" 200 612 "-" "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like G
2020-10-05T05:17:31.433713897Z 100.110.232.4 - - [05/Oct/2020:05:17:31 +0000] "GET /favicon.ico HTTP/1.1" 404 555 "http://web.devopsman.cn/" "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/85.0.4183.121 Safari/537.36" "192.168.99.1"
2020-10-05T05:17:49.607617864Z 100.110.232.4 - - [05/Oct/2020:05:17:49 +0000] "GET / HTTP/1.1" 200 612 "-" "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/85.0.4183.121 Safari/537.36" "192.168.99.1"

通过label过滤想查看的所有pod的日志

☸️  CloudnativeEcosystem? default  ~  ? ? k logs -f -l app=nginx 
/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

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原始发表：2020-10-20，如有侵权请联系 cloudcommunity@tencent.com 删除

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