Kubertenets -

Orquestrador de containers - gerencia clusters

POD - encapsula um container - pode conter um ou mais containers

Kubeclt - interrage com a API que por sua vez altera no cluster

Deletar todos os pods

> kubectl delete pods --all

Comando de rodar um pod

PS F:\> kubectl run nginx-pod --image=nginx:latest

PS F:\> kubectl get pods

NAME READY STATUS RESTARTS AGE

nginx-pod 1/1 Running 0 2m59s

PS F:\>

PS C:\Users\User\Desktop\KUBERNETES> kubectl get pods -o wide

NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES

portal-noticias 1/1 Running 0 17m 10.1.0.8 docker-desktop <none> <none>

primeiro-pod-lucas 1/1 Running 0 41m 10.1.0.7 docker-desktop <none> <none>

PS C:\Users\User\Desktop\KUBERNETES>

Detalhes do pod

PS F:\> kubectl describe pod nginx-pod

Name: nginx-pod

Namespace: default

Priority: 0

Node: docker-desktop/192.168.65.4

Start Time: Fri, 01 Jul 2022 22:09:06 -0300

Labels: run=nginx-pod

Annotations: <none>

Status: Running

IP: 10.1.0.6

IPs:

IP: 10.1.0.6

Containers:

nginx-pod:

Container ID: docker://fe01baaaa0c1b2ef5c4698566daed4b2c6f1a461b7ad463426fa74aacbbe2060

Image: nginx:latest

Image ID: docker-pullable://nginx@sha256:10f14ffa93f8dedf1057897b745e5ac72ac5655c299dade0aa434c71557697ea

Port: <none>

Host Port: <none>

State: Running

Started: Fri, 01 Jul 2022 22:09:19 -0300

Ready: True

Restart Count: 0

Environment: <none>

Mounts:

/var/run/secrets/kubernetes.io/serviceaccount from kube-api-access-5mrtt (ro)

Conditions:

Type Status

Initialized True

Ready True

ContainersReady True

PodScheduled True

Volumes:

kube-api-access-5mrtt:

Type: Projected (a volume that contains injected data from multiple sources)

TokenExpirationSeconds: 3607

ConfigMapName: kube-root-ca.crt

ConfigMapOptional: <nil>

DownwardAPI: true

QoS Class: BestEffort

Node-Selectors: <none>

Tolerations: node.kubernetes.io/not-ready:NoExecute op=Exists for 300s

node.kubernetes.io/unreachable:NoExecute op=Exists for 300s

Events:

Type Reason Age From Message

---- ------ ---- ---- -------

Normal Scheduled 3m55s default-scheduler Successfully assigned default/nginx-pod to docker-desktop

Normal Pulling 3m54s kubelet Pulling image "nginx:latest"

Normal Pulled 3m43s kubelet Successfully pulled image "nginx:latest" in 11.3828416s

Normal Created 3m42s kubelet Created container nginx-pod

Normal Started 3m42s kubelet Started container nginx-pod

Atualizar a imagem do pod

PS F:\> kubectl edit pod nginx-pod

Abre um bloco de notas para editar o arquivo do pod

Alterado a versão do service nginx

spec:

containers:

- image: nginx:1.0

imagePullPolicy: Always

resources: {}

terminationMessagePath: /dev/termination-log

terminationMessagePolicy: File

volumeMounts:

- mountPath: /var/run/secrets/kubernetes.io/serviceaccount

erro

PS F:\> kubectl get pods

NAME READY STATUS RESTARTS AGE

nginx-pod 0/1 ImagePullBackOff 0 (20s ago) 6m50s

Editando e criando arquivo de pods

apiVersion: v1

kind: Pod

metadata:

spec:

containers:

- name: nginx-container

image: nginx:1.0

PS C:\Users\User\Desktop\KUBERNETES> ls

Diretório: C:\Users\User\Desktop\KUBERNETES

Mode LastWriteTime Length Name

---- ------------- ------ ----

-a---- 01/07/2022 22:24 153 primeiro-pod.yaml

PS C:\Users\User\Desktop\KUBERNETES> kubectl apply -f .\primeiro-pod.yaml

pod/primeiro-pod-lucas created

PS C:\Users\User\Desktop\KUBERNETES>

DELETANDO POD

PS C:\Users\User\Desktop\KUBERNETES> kubectl delete pod nginx-pod

pod "nginx-pod" deleted

PS C:\Users\User\Desktop\KUBERNETES>

Acessando o container em modo interativo

PS C:\Users\User\Desktop\KUBERNETES> kubectl exec -it portal-noticias bash

kubectl exec [POD] [COMMAND] is DEPRECATED and will be removed in a future version. Use kubectl exec [POD] -- [COMMAND] instead.

root@portal-noticias:/var/www/html#

root@portal-noticias:/var/www/html# ls

configuracao.php content.html docker-compose.yml index.php theme

root@portal-noticias:/var/www/html#

SERVICES - SVC

Expoe as aplicações para mundo externo com dns e ipfixo e loadbalance

ClusterIP interna

Permite entre os pods internamente localmente, cada pod tem que ter um serviço agregado para ser acessado

NodePort

Permite acesso externo - da nossa maquina fisica para o pod

ele ja se adiciona a clusterIP e pode ser acessando pelas maquinas de dentro do cluster

LoadBalancer

Se aloca ao load balancer da provider aws google cloud azure normalmente o que muda no codigo é apenas o type para loadbalancer

Arquivo pod1.yaml

apiVersion: v1

kind: Pod

metadata:

labels:

app: primeiro-pod

spec:

containers:

- name: pod1

image: nginx:stable

ports:

- containerPort: 80

A label que permite o servico selecionar esse pod e aplicar a configuracao

arquivo svc-pod1.yaml

apiVersion: v1

kind: Service

metadata:

spec:

type: NodePort

ports:

- port: 80

targetPort: 80

selector:

app: primeiro-pod

MINIKUBE DASHBOAD INSTALACAO

minikube dashboard

exemplos

https://github.com/alura-cursos/kubernetes-3/tree/Aula_2

cronjobs e um recurso do kubernetes para usar um agendador e executar tarefdas como backup

FROM mysql

COPY dump.sh /

RUN chmod +x /dump.sh

ENTRYPOINT ["/dump.sh"]

dump.sh

#!/bin/bash

DB_USER=${DB_USER: -${MYSQL_ENV_DB_USER}}

DB_PASS=${DB_PASS: -${MYSQL_ENV_DB_PASS}}

DB_HOST=${DB_HOST: -${MYSQL_ENV_DB_HOST}}

if [[ ${DB_USER} =="" ]]; then

echo "Missing DB_USER env variable"

exit 1

fi

if [[ ${DB_PASS} =="" ]]; then

echo "Missing DB_PASS env variable"

exit 1

fi

if [[ ${DB_HOST} =="" ]]; then

echo "Missing DB_HOST env variable"

exit 1

fi

//código omitido

https://kubernetes.io/docs/concepts/workloads/controllers/cron-jobs/

STATEFUL SET = BANCO DE DADOS AO INVES DE DEPLOY vi