目錄表

Kubectl 語法整理

Kubectl 語法整理

指定特別 kubeconf 檔方式

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

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

檢查 K8s Cluster 的健康狀態

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"}

讀取 K8s Cluster Name 的方式

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

顯示 K8s 內的 POD 清單

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

顯示 K8s 內 POD 的 logs

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

顯示 K8s 內 POD 的描述資訊

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

進入一個 POD 內操作

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

顯示 K8s 內的 deploy 清單

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

移除 K8s 內的 deploy pod

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

顯示 K8s 內的 namespace 清單

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

移除 K8s 內的 namespace deploy pod

kubctl delete namespace [namespace NAME]

Exp.

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

讀取 Secret 的內容

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

讀取 kubelet 內的 pod 目錄編號

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