Kubectl 語法整理

Exp. kubeconf 檔案存放在 /iiidevops/kube-config/config

kubectl --kubeconfig /iiidevops/kube-config/config get pod

參考 - https://stackoverflow.com/questions/54882727/kubectl-using-command-to-get-cluster-status

kubectl get componentstatus

結果類似以下訊息:

$ kubectl get componentstatus
NAME                 STATUS    MESSAGE             ERROR
controller-manager   Healthy   ok
scheduler            Healthy   ok
etcd-0               Healthy   {"health":"true"}

參考 - https://stackoverflow.com/questions/38242062/how-to-get-kubernetes-cluster-name-from-k8s-api

方法1

kubectl config current-context

結果:

rkeuser@devops2:~$ kubectl config current-context
iiidevops-k8s

方法2

kubectl config view

結果:

rkeuser@devops2:~$ kubectl config view
apiVersion: v1
clusters:
- cluster:
    certificate-authority-data: DATA+OMITTED
    server: https://172.16.0.172:6443
  name: iiidevops-k8s
contexts:
- context:
    cluster: iiidevops-k8s
    user: kube-admin-iiidevops-k8s
  name: iiidevops-k8s
current-context: iiidevops-k8s
kind: Config
preferences: {}
users:
- name: kube-admin-iiidevops-k8s
  user:
    client-certificate-data: REDACTED
    client-key-data: REDACTED

kubectl get pod

Exp.

localadmin@iiidevops-73:~$ kubectl get pod
NAME                                  READY   STATUS    RESTARTS   AGE
devopsapi-dbbcf7fd4-j5nv2             1/1     Running   0          36m
devopsdb-5555449b8d-rd2z9             1/1     Running   0          37m
devopsui-84496c7fcc-bd99r             1/1     Running   0          126m
redmine-547cbdbbbb-wk9s6              1/1     Running   1          17h
redmine-postgresql-6fb9475c6c-gs9gh   1/1     Running   0          17h
sonarqube-server-6ccbf4c54f-vksmp     1/1     Running   0          17h

加上 -n 參數指定所要查詢的 namespace 內 pod 清單

kubectl get pod -n kube-system

Exp.

$ kubectl get pod -n kube-system
NAME                                      READY   STATUS      RESTARTS   AGE
calico-kube-controllers-c955d588c-kcm7r   1/1     Running     2          36h
calico-node-sghsm                         1/1     Running     2          36h
:
rke-metrics-addon-deploy-job-dhjbl        0/1     Completed   0          36h
rke-network-plugin-deploy-job-6vzqh       0/1     Completed   0          36h

加上 -A 參數可呈現所有 namespace 的 pod 清單

kubectl get pod -A

Exp.

localadmin@iiidevops-hv-2:~$ kubectl get pod -A
NAMESPACE          NAME                                       READY   STATUS      RESTARTS   AGE
cattle-pipeline    registry-proxy-96bbj                       1/1     Running     0          40m
cattle-system      cattle-cluster-agent-7d569b986c-57485      1/1     Running     0          145m
:
kube-system        rke-metrics-addon-deploy-job-tb2sn         0/1     Completed   0          146m
kube-system        rke-network-plugin-deploy-job-pcgss        0/1     Completed   0          146m
p-8kvwh-pipeline   docker-registry-57fbddc6cc-ch9cw           1/1     Running     0          40m
p-8kvwh-pipeline   jenkins-f4d6b89cb-h8554                    1/1     Running     0          40m
p-8kvwh-pipeline   minio-5ccb99b5c7-kp9lc                     1/1     Running     0          40m

kubectl logs [pod NAME]

Exp.

localadmin@iiidevops-73:~$ kubectl logs redmine-547cbdbbbb-wk9s6 | tail -20
I, [2020-12-21T10:47:03.089762 #1]  INFO -- :   Rendered enumerations/_form.html.erb (2.8ms)
I, [2020-12-21T10:47:03.090267 #1]  INFO -- :   Rendered enumerations/new.html.erb within layouts/admin (4.2ms)
I, [2020-12-21T10:47:03.095432 #1]  INFO -- :   Rendered admin/_menu.html.erb (4.9ms)
I, [2020-12-21T10:47:03.095745 #1]  INFO -- :   Rendering layouts/base.html.erb
I, [2020-12-21T10:47:03.107140 #1]  INFO -- :   Rendered layouts/base.html.erb (11.3ms)
I, [2020-12-21T10:47:03.107464 #1]  INFO -- : Completed 200 OK in 32ms (Views: 19.9ms | ActiveRecord: 5.8ms)
I, [2020-12-21T10:47:05.101236 #1]  INFO -- : Started POST "/enumerations" for 10.20.0.74 at 2020-12-21 10:47:05 +0000
I, [2020-12-21T10:47:05.102407 #1]  INFO -- : Processing by EnumerationsController#create as HTML
I, [2020-12-21T10:47:05.102487 #1]  INFO -- :   Parameters: {"utf8"=>"✓", "authenticity_token"=>"wRaItdciacpkIjcxxxxxxxxxxrdQWdKf66WuZPq6AGAIQyK9BLeuyOlyKODKQedaCNdAoADOadTy+3UH4mTeg==", "enumeration"=>{"type"=>"IssuePriority", "name"=>"Low", "active"=>"1", "is_default"=>"0"}, "commit"=>"Create"}
I, [2020-12-21T10:47:05.112128 #1]  INFO -- :   Current user: admin (id=1)
I, [2020-12-21T10:47:05.192218 #1]  INFO -- : Redirected to http://10.20.0.74:32748/enumerations
I, [2020-12-21T10:47:05.192469 #1]  INFO -- : Completed 302 Found in 90ms (ActiveRecord: 17.5ms)
10.20.0.74 - - [21/Dec/2020:10:47:05 UTC] "POST /enumerations HTTP/1.1" 302 102
http://10.20.0.74:32748/enumerations/new?type=IssuePriority -> /enumerations
10.20.0.74 - - [21/Dec/2020:10:47:05 UTC] "GET /enumerations HTTP/1.1" 200 8526
http://10.20.0.74:32748/enumerations/new?type=IssuePriority -> /enumerations
10.20.0.74 - - [22/Dec/2020:02:21:47 UTC] "GET /users/current.json HTTP/1.1" 200 253
- -> /users/current.json
10.20.0.74 - - [22/Dec/2020:02:21:47 UTC] "GET /users.json?offset=0&limit=25&key=d64c31axxxxxxxxxxd085fc5825ec257b31a3ec7 HTTP/1.1" 200 230
- -> /users.json?offset=0&limit=25&key=d64c31aff3xxxxxxxxxx5fc5825ec257b31a3ec7

kubectl describe pod [pod NAME]

Exp.

localadmin@iiidevops-71:~/deploy-devops$ kubectl describe pod devopsapi-cdccbcb48-qv4n9
Name:         devopsapi-cdccbcb48-qv4n9
Namespace:    default
Priority:     0
Node:         iiidevops-72/10.20.0.72
Start Time:   Thu, 24 Dec 2020 06:27:37 +0000
Labels:       app=devopsapi
              pod-template-hash=cdccbcb48
:
:
  Normal   Pulling         15s (x2 over 38s)  kubelet            Pulling image "iiiorg/devops-api:develop"
  Warning  Failed          11s (x2 over 34s)  kubelet            Failed to pull image "iiiorg/devops-api:develop": rpc error: code = Unknown desc = Error response from daemon: toomanyrequests: You have reached your pull rate limit. You may increase the limit by authenticating and upgrading: https://www.docker.com/increase-rate-limit
  Warning  Failed          11s (x2 over 34s)  kubelet            Error: ErrImagePull

kubectl exec -it [POD Name] -- bash

Exp.

localadmin@iiidevops-hv-2:~$ kubectl exec -it devopsapi-74c78bb4c8-77phj -- bash
root@devopsapi-74c78bb4c8-77phj:/usr/src/app# ls -lt
total 76
drwxr-xr-x 1 root root  4096 Jan 23 08:18 apis
drwxrwxrwx 2 root root  4096 Jan 23 08:18 logs
-rw-r--r-- 1 root root    41 Jan 22 22:15 git_commit
-rwxr-xr-x 1 root root   435 Jan 22 22:15 Dockerfile
-rwxr-xr-x 1 root root 11357 Jan 22 22:15 LICENSE
-rwxr-xr-x 1 root root   878 Jan 22 22:15 README.md
-rwxr-xr-x 1 root root  1994 Jan 22 22:15 _alembic.ini
:
:
-rwxr-xr-x 1 root root  3133 Jan 22 22:15 k8s_config
root@devopsapi-c9ddc8cdf-mrb9f:/usr/src/app#

如果要進入不同 namespace 的 pod 操作就需要加上 –namespace=“xxx” 的參數 Exp.

localadmin@iiidevops-hv-2:~$ kubectl exec -it --namespace="p-8kvwh-pipeline" minio-5ccb99b5c7-kp9lc  -- traceroute 172.17.13.183
traceroute to 172.17.13.183 (172.17.13.183), 30 hops max, 46 byte packets
 1  172-17-13-183.kubernetes.default.svc.cluster.local (172.17.13.183)  0.007 ms  0.009 ms  0.007 ms

kubctl get deploy

Exp.

localadmin@iiidevops-73:~$ kubectl get deploy
NAME                 READY   UP-TO-DATE   AVAILABLE   AGE
devopsapi            1/1     1            1           17h
devopsdb             1/1     1            1           37m
devopsui             1/1     1            1           17h
redmine              1/1     1            1           17h
redmine-postgresql   1/1     1            1           17h
sonarqube-server     1/1     1            1           17h

kubctl delete deploy [deploy NAME]

Exp.

localadmin@iiidevops-73:~$ kubectl delete deploy devopsui devopsdb devopsapi
deployment.apps "devopsui" deleted
deployment.apps "devopsdb" deleted
deployment.apps "devopsapi" deleted

kubctl get namespace

Exp.

iiidevops@iiidevops1:~$ kubectl get namespace
NAME                   STATUS   AGE
account                Active   49d
cattle-pipeline        Active   6d22h
cattle-system          Active   50d
default                Active   50d
iii-devops-toolchain   Active   6d22h
ingress-nginx          Active   50d
kube-node-lease        Active   50d
kube-public            Active   50d
kube-system            Active   50d
p-pdx2d-pipeline       Active   6d22h
security-scan          Active   50d

kubctl delete namespace [namespace NAME]

Exp.

iiidevops@iiidevops1:~$ kubectl delete namespace iii-devops-toolchain
namespace "iii-devops-toolchain" deleted

kubectl get secret [secret_name]

Exp.

rkeuser@dev4-86:~$ kubectl get secret
NAME                                    TYPE                                  DATA   AGE
default-token-pssx6                     kubernetes.io/service-account-token   3      21d
gitlab                                  Opaque                                1      21d
harbor                                  Opaque                                1      21d
harbor-harbor-clair                     Opaque                                3      21d
harbor-harbor-clair-internal-tls        kubernetes.io/tls                     3      21d
harbor-harbor-core                      Opaque                                8      21d
:

顯示 secret 的內容, 有定義那些 key

kubectl describe secret [secret_name]

Exp.

rkeuser@dev4-86:~$ kubectl describe secret harbor
Name:         harbor
Namespace:    default
Labels:       <none>
Annotations:  field.cattle.io/creatorId: user-jwvbx
              field.cattle.io/projectId: local:p-rhflt
              lifecycle.cattle.io/create.secretsController_local: true
              secret.user.cattle.io/secret: true

Type:  Opaque

Data
====
harbor-local:  25 bytes

顯示 secret key 的 value 編碼內容

kubectl get secrets/<secret_name> --template={{.data.<key>}}

Exp.

kubectl get secrets/harbor --template={{.data.harbor-local}}

如果要直接解碼可使用 base64 -d 的方式處理 Exp.

kubectl get secrets/harbor --template={{.data.harbor-local}} | base64 -d

實際 pod 的檔案存在 node 內的 /var/lib/kubelet/pods 內, 可透過以下語法獲知 pod 的目錄編號

kubectl get pods -A -o custom-columns=NodeName:.spec.nodeName,PodName:.metadata.name,PodUID:.metadata.uid

看實際範例

rkeuser@demo-77:~$ kubectl get pods -A -o custom-columns=NodeName:.spec.nodeName,PodName:.metadata.name,PodUID:.metadata.uid
NodeName     PodName                                                           PodUID
10.20.0.79   a1-master-db-dpy-79bc97bf96-xmqxw                                 34dad11c-7f38-44c1-b1b0-e06d760d2a7e
10.20.0.79   a1-master-db-gui-7cc89bcb59-vlhtz                                 9cc444c9-3986-4ba2-a535-9f44f6bb10cf
10.20.0.79   a1-master-sq-4-wkv2l                                              94dc6771-bea0-46bd-a0ec-0128e7c5c16d
10.20.0.78   apeg-python-flask-master-serv-dpy-86b655666-9ngdf                 0903dcd1-c1f5-4704-b8ba-7991d11e882d
10.20.0.78   aptgit-220209-master-db-dpy-5f7986d9c-wvv2c                       7209d08f-d0b8-428d-922c-87b3f6fe5787
10.20.0.77   aptgit-220209-master-db-gui-67bbbf77cb-h9qxh                      498451f9-fa3a-4fa6-bd2c-dd1ae1d9a3b7
10.20.0.79   aptgit-220209-master-db-gui-67bbbf77cb-t79qf                      ba6e310c-a106-426e-910a-290e836c40a9
10.20.0.78   aptgit-220209-master-serv-dpy-5cf7cccd4d-66vns                    522553e2-3323-44cb-bb02-3995d625c033
10.20.0.77   aptgit-220209-master-serv-dpy-5cf7cccd4d-k2jl8                    f8a147db-3eee-4d40-b051-f6b00bc0a644
:

直接看 aptgit-220209-master-db-gui-67bbbf77cb-h9qxh → 498451f9-fa3a-4fa6-bd2c-dd1ae1d9a3b7 這個 POD 的檔案

rkeuser@demo-77:~$ sudo ls -lRt /var/lib/kubelet/pods/498451f9-fa3a-4fa6-bd2c-dd1ae1d9a3b7
/var/lib/kubelet/pods/498451f9-fa3a-4fa6-bd2c-dd1ae1d9a3b7:
total 16
-rw-r--r-- 1 root root  241 Jan  7 09:04 etc-hosts
drwxr-x--- 3 root root 4096 Jun 25  2022 containers
drwxr-x--- 3 root root 4096 Jun 25  2022 plugins
drwxr-x--- 3 root root 4096 Jun 25  2022 volumes

/var/lib/kubelet/pods/498451f9-fa3a-4fa6-bd2c-dd1ae1d9a3b7/containers:
total 4
drwxr-x--- 2 root root 4096 Jan  7 09:04 mariadb-gui

/var/lib/kubelet/pods/498451f9-fa3a-4fa6-bd2c-dd1ae1d9a3b7/containers/mariadb-gui:
total 0
-rw-rw-rw- 1 root root 0 Jan  7 09:04 832a851d
-rw-rw-rw- 1 root root 0 Nov 19 09:26 d65ebd13
-rw-rw-rw- 1 root root 0 Oct 15 06:39 d516d827
-rw-rw-rw- 1 root root 0 Oct 14 19:16 ea72f4fc
-rw-rw-rw- 1 root root 0 Sep 17 11:11 94285167
-rw-rw-rw- 1 root root 0 Aug 28 18:14 edc19f39
-rw-rw-rw- 1 root root 0 Jul 30  2022 cbf94e15
-rw-rw-rw- 1 root root 0 Jul 14  2022 f3f9f859
-rw-rw-rw- 1 root root 0 Jun 25  2022 46143b63

/var/lib/kubelet/pods/498451f9-fa3a-4fa6-bd2c-dd1ae1d9a3b7/plugins:
total 4
drwxr-x--- 2 root root 4096 Jan 30 07:48 kubernetes.io~empty-dir

/var/lib/kubelet/pods/498451f9-fa3a-4fa6-bd2c-dd1ae1d9a3b7/plugins/kubernetes.io~empty-dir:
total 0

/var/lib/kubelet/pods/498451f9-fa3a-4fa6-bd2c-dd1ae1d9a3b7/volumes:
total 4
drwxr-xr-x 2 root root 4096 Jan 30 07:48 kubernetes.io~secret

/var/lib/kubelet/pods/498451f9-fa3a-4fa6-bd2c-dd1ae1d9a3b7/volumes/kubernetes.io~secret:
total 0
rkeuser@demo-77:~$

k8s, iiidevops, kubectl

Num	Page	Accesses
1	tech:fortigate_tips	838
2	tech:win10_hash	718
3	start	477
4	tech:ubuntu_xrdp	452
5	tech:pvetips	396
6	tech:nfs	363
7	tech:sqlsrv	291
8	tech:zfs	227
9	tech:pbstips	224
10	tech:win10snmpd	211

Kubectl 語法整理

指定特別 kubeconf 檔方式

檢查 K8s Cluster 的健康狀態

讀取 K8s Cluster Name 的方式

顯示 K8s 內的 POD 清單

顯示 K8s 內 POD 的 logs

顯示 K8s 內 POD 的描述資訊

進入一個 POD 內操作

顯示 K8s 內的 deploy 清單

移除 K8s 內的 deploy pod

顯示 K8s 內的 namespace 清單

移除 K8s 內的 namespace deploy pod

讀取 Secret 的內容

讀取 kubelet 內的 pod 目錄編號