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https://github.com/claudio-code/k8s-ckad-simulated

:memo: Preparing to take the certification
https://github.com/claudio-code/k8s-ckad-simulated

k8s

Last synced: 7 months ago
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:memo: Preparing to take the certification

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# k8s-ckad-simulated



### Change k8s editor to nano



```bash



echo "source <(kubectl completion bash)" >> ~/.bashrc



autoload -U +X bashcompinit && bashcompinit

autoload -U +X compinit && compinit



export KUBE_EDITOR=nano



alias la='ls -A'

alias ll='ls -alF'

alias l='ls -CF'



alias k=kubectl

complete -F __start_kubectl k

alias kgp='kubectl get pod'

alias kd='kubectl describe'

export d="--dry-run=client -o yaml"



## Config nano

nano .nanorc



set tabsize 2

set tabstospaces



## Config vim



vim .vimrc



set expandtab

set autochdir

set tabstop=2

set shiftwidth=2

syntax on

```



### Command to create cronjob with command

```bash

kubectl create cronjob --image=ubuntu --schedule="* * * * *" --dry-run=client -o yaml > my-file.yaml

```



### Command to create resource quota in kubectl



```bash

kubectl create quota quota2 --hard pod=2,cpu=2,memory=1Gi --dry-run=client -o yaml

```



### Command to found resource using api-resource in kubectl



```bash

kubectl api-resources -o wide | grep 

```



### Command to verify if user was permission in many different resources in k8s



```bash

kubectl auth can-i get secrets --as system:serviceaccount:default:reader

```



### Create Role with command



```bash

kubectl create role leitor2 --verb get,watch, list --resource secrets --dry-run=client -o yaml

```



### Create ClusterRole with command



```bash

kubectl create clusterrole readerTwo --verb get, watch, list --resource secrets --dry-run=client -o yaml

```



### Create ServiceAccount



```bash

kubectl create sa reader --dry-run=client -o yaml

### Create Ingress in kubectl command line



```bash

## ingress by path

k create ingress ingress2 --class nginx --rule="/foo=foo-nginx:80" --dry-run=client -o yaml



## ingress by host

k create ingress ingress2 --class nginx --rule="foo.possuidao.xyy/foo=foo-nginx:80" --dry-run=client -o yaml

```



### Filter outputs in when get infos of kubectl



```bash



k get pods -o=name > /tmp/pods



```



### Force delete/replace pod



```bash



## to delete

k delete po pod-name --force --grace-period 0



## to replace

k replace -f ./manifest.yaml --force --grace-period 0



```



### Create deployment and generate manifest



```bash

k create deployment firstdeploy --image=nginx --dry-run=client -o yaml > firstdeploy.yaml

```



### Create pod and generate manifest



```bash



k run nginx --image nginx --port 80 --dry-run=client -o yaml > manifest-pod.yaml



```



### Create service in command line



```bash

k expose pod pod-name --target-port 80 --port 80

```



### Pass command to execute in pod



```bash

k exec -it second-pod -- curl 10.42.0.2

```



### Get info of pod and print manifest in terminal



```bash



k get po pod-name -o yaml



```



### Delete all pods



```bash



k delete --all pods



# OR



k delete --all po



# OR OF SPECIFIC NAMESPACE



k delete --all po --namespace=default



```



### Enter in pod with two containers



```bash



k exec -it nginx -c nginx -- bash



```



### Get all info of specific pod



```bash



k describe po nginx



```



### Find how make configs in manifest with terminal doc



```bash



### Complete info

k explain pod.spec.containers



### Just examples

k explain pod.spec.containers --recursive



```



### Force delete pod



```bash

k delete po my-pod nginx sleep --force --grace-period 0

```



### Create deployment more fast



```bash

k create deployment nginx --image nginx -o yaml --dry-run=client > replica-set-two.yaml

```



### How edit deployment when it is running



```bash

k edit deployments.app first-deploy

## OR

k edit deploy first-deploy

```



### How set scale in deployment running



```bash

k scale deployment --replica 6 first-deploy

## OR

k scale deploy --replica 1 first-deploy

```



### How see all changes in deployment



```bash

k rollout history deployment first-deploy

## OR

k rollout history deploy first-deploy

```



### Make rollback to previous version



```bash

k rollout undo --to-revision 1 deploy first-deploy

```



### Generate manifest of pod



```bash

k run nginx --image nginx --dry-run=client -o yaml > pod-pvc.yaml

```



---



## PersistentVolumeClaim



```yaml

apiVersion: v1

kind: PersistentVolumeClaim

metadata:

  name: pvc-first

spec:

  accessModes:

    - ReadWriteOnce

  resources:

    requests:

      storage: 1Gi

```



### PersistentVolumeClaim to test



> spec



#### accessModes



```yaml

accessModes:

  - [ReadWriteOnce | ReadOnlyMany | ReadWriteMany]

```



- ReadWriteOnce: The volume can mount with read and write by only node.

- ReadOnlyMany: The volume can mount only read to many nodes.

- ReadWriteMany: The volume can mount with read and write to many nodes.



#### class



> Determine which will be the storageClass to PV will use.



```yaml

storageClassName: "Slow"

```



#### resources



> Like pods can solicit specifics quantities of one resource. the solicitation is to storage.



```yaml

resources:

  requests:

    storage: 9Gi

```



#### volumeName



> Force the use specific PV



```yaml

volumeName: firstPV

```



#### selector



> The PVCS can specific one "label selector" to filter further process to one PV



```yaml

selector: # [matchLabels | matchExpressions]

  matchLabels:

    release: "dev"

  mathExpression:

    - { key: enviroment, operator: In, values: [dev] }

```



- matchLabels: The volume must have one label with it value.

- matchExpressions: One list of requirements made specific key, list of values and operator to relate key and operator. The operators valid include in, notIn, Exists and DoesNotExists.



#### Example in pod



```yaml

apiVersion: v1

kind: Pod

metadata:

  labels:

    run: nginx

  name: nginx

  namespace: day1

spec:

  containers:

    - image: nginx

      name: nginx

      volumeMounts:

        - name: usingpvc

          mountPath: /data

  dnsPolicy: ClusterFirst

  restartPolicy: Always

  volumes:

    - name: usingpvc

      persistentVolumeClaim:

        claimName: pvc-first

```



---



## PersistentVolume



```yaml

apiVersion: v1

kind: PersistentVolume

metadata:

  name: firstPV

spec:

  storageClassName: ""

  capacity:

    storage: 1Gi

  accessModes:

    - ReadWriteOnce

  hostPath:

    path: "/home"

```



### PersistentVolume to test



> spec



#### Capacity



Specific storage size of persistence volume ( Gi Mi )



```yaml

capacity:

  storage: 1Gi

```



#### VolumeMode



```yaml

volumeMode: [Filesystem | Block]

```



#### AccessMode



```yaml

accessMode:

  - [ReadWriteOnce | ReadOnlyMany | ReadWriteMany]

```



- ReadWriteOnce: The volume could it be mounted with read and write to one node.

- ReadOnlyMany: The volume could it be mounted with only read to many nodes.

- ReadWriteMany: The volume could it be mounted with read and write to many nodes.



#### Reclaim Policy



> It option has the objective the action that the cluster will make after exclude PVC.



```yaml

persistentVolumeReclaimPolicy: [Retain | Recycle | Delete]

```



- Retain: Need one manual action.

- Recycle: basic (rm -rf /volumeDir/\*).

- Delete: Using AWS EBS, GCE PD, Azure Disk or OpenStack Cinder the volume as deleted.



#### Class



> Determine which will be the storageClass to PV will use.



```yaml

storageClassName: "Slow"

```



#### HostPath



> One volume hostPath mount one file or directory of filesystem of node of host in your pod.



```yaml

hostPath:

  path:

  type: [FileOrCreate | DirectoryOrCreate]

```



- FileOrCreate: If nothing exist in path provided, one file empty will be created there as need with permission like 0644, having the same group and properties of kubelet.

- DirectoryOrCreate: If no exist in path provided, one directory empty will be created there as need with defined permission like 0755, having the same group and property of kubelet.



## ConfigMap and Secrets



### How fast create configMap



````yaml

k create configmap second-cm --from-literal=ip=22.2.2.22 --from-literal=server=web --dry-run=client -o yaml

## Secret



Secret encode all values in base64 you can test it encode using it command:



Encode:



```bash

  echo -n "senha" | base64

````



Decode:



```bash

  echo -n "dXNlcg==" | base64 -d

```



### Create secret from file



```bash

k create secret generic my-secret --from-file=./secrets.txt --from-file=./another-secrets.txt

```



### Create secret literal



```bash

k create secret generic my-secret --from-literal=user=admin --from-literal=pass=mysecretpass

```



### Create secret to docker register



```bash

k create secret docker-registry my-docker \

  --docker-username=admin \

  --docker-password=pass123 \

  --docker-email=admin@soneca.corp.com

```